From: Bruce Momjian Date: Mon, 23 Sep 2002 01:59:40 +0000 (+0000) Subject: Add win32 rename discussion to archives. X-Git-Tag: REL7_3~412 X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=8ffec958bc198e6b807f42d2b2b0f96f8fc74aef;p=postgresql Add win32 rename discussion to archives. --- diff --git a/doc/TODO.detail/win32 b/doc/TODO.detail/win32 index 02a1083107..f35c5c6fe1 100644 --- a/doc/TODO.detail/win32 +++ b/doc/TODO.detail/win32 @@ -6475,7 +6475,7 @@ X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2600.0000 X-Spam-Status: Yes, hits=5.0 required=5.0 tests=RCVD_IN_OSIRUSOFT_COM,X_OSIRU_SPAM_SRC version=2.20 X-Spam-Flag: YES X-Spam-Level: ***** -X-Spam-Checker-Version: SpamAssassin 2.20 (devel $Id: win32,v 1.3 2002/09/16 02:50:20 momjian Exp $) +X-Spam-Checker-Version: SpamAssassin 2.20 (devel $Id: win32,v 1.4 2002/09/23 01:59:40 momjian Exp $) X-Spam-Report: Detailed Report SPAM: -------------------- Start SpamAssassin results ---------------------- SPAM: This mail is probably spam. The original message has been altered @@ -7565,3 +7565,3009 @@ TIP 5: Have you checked our extensive FAQ? http://www.postgresql.org/users-lounge/docs/faq.html +From pgsql-hackers-owner+M29089@postgresql.org Thu Sep 19 01:07:35 2002 +Return-path: +Received: from postgresql.org (postgresql.org [64.49.215.8]) + by candle.pha.pa.us (8.11.6/8.10.1) with ESMTP id g8J57XE17033 + for ; Thu, 19 Sep 2002 01:07:34 -0400 (EDT) +Received: from localhost (postgresql.org [64.49.215.8]) + by postgresql.org (Postfix) with ESMTP + id C4A62476A3C; Thu, 19 Sep 2002 01:07:34 -0400 (EDT) +Received: from postgresql.org (postgresql.org [64.49.215.8]) + by postgresql.org (Postfix) with SMTP + id A818A4760B0; Thu, 19 Sep 2002 01:07:32 -0400 (EDT) +Received: from localhost (postgresql.org [64.49.215.8]) + by postgresql.org (Postfix) with ESMTP id 4E7414769C9 + for ; Thu, 19 Sep 2002 01:07:26 -0400 (EDT) +Received: from ece.rice.edu (ece.rice.edu [128.42.4.34]) + by postgresql.org (Postfix) with ESMTP id B6B5447590C + for ; Thu, 19 Sep 2002 01:07:24 -0400 (EDT) +Received: from localhost (localhost [127.0.0.1]) + by ece.rice.edu (Postfix) with ESMTP + id 337C368A68; Thu, 19 Sep 2002 00:07:24 -0500 (CDT) +Received: from wallace.ece.rice.edu (wallace.ece.rice.edu [128.42.12.154]) + by ece.rice.edu (Postfix) with ESMTP + id 1EF0D68A65; Thu, 19 Sep 2002 00:07:23 -0500 (CDT) +Received: from reedstrm by wallace.ece.rice.edu with local (Exim 3.34 #1 (Debian)) + id 17rtX8-00042E-00; Thu, 19 Sep 2002 00:07:22 -0500 +Date: Thu, 19 Sep 2002 00:07:22 -0500 +From: "Ross J. Reedstrom" +To: Bruce Momjian +cc: PostgreSQL-development +Subject: Re: [HACKERS] Win32 rename()/unlink() questions +Message-ID: <20020919050722.GC15352@rice.edu> +Mail-Followup-To: "Ross J. Reedstrom" , + Bruce Momjian , + PostgreSQL-development +References: <200209190001.g8J01gG13849@candle.pha.pa.us> +MIME-Version: 1.0 +Content-Type: text/plain; charset=us-ascii +Content-Disposition: inline +In-Reply-To: <200209190001.g8J01gG13849@candle.pha.pa.us> +User-Agent: Mutt/1.3.27i +X-Virus-Scanned: by AMaViS snapshot-20020300 +X-Virus-Scanned: by AMaViS new-20020517 +Precedence: bulk +Sender: pgsql-hackers-owner@postgresql.org +X-Virus-Scanned: by AMaViS new-20020517 +Status: OR + +On Wed, Sep 18, 2002 at 08:01:42PM -0400, Bruce Momjian wrote: + +> Second, when you unlink() a file on Win32, do applications continue +> accessing the old file contents if they had the file open before the +> unlink? + +I'm pretty sure it errors with 'file in use'. Pretty ugly, huh? + +Ross + + +---------------------------(end of broadcast)--------------------------- +TIP 1: subscribe and unsubscribe commands go to majordomo@postgresql.org + +From mascarm@mascari.com Thu Sep 19 01:24:42 2002 +Return-path: +Received: from corvette.mascari.com (dhcp065-024-158-068.columbus.rr.com [65.24.158.68]) + by candle.pha.pa.us (8.11.6/8.10.1) with ESMTP id g8J5ObE18446 + for ; Thu, 19 Sep 2002 01:24:40 -0400 (EDT) +Received: from mascari.com (ferrari.mascari.com [192.168.2.1]) + by corvette.mascari.com (8.9.3/8.9.3) with ESMTP id BAA15293; + Thu, 19 Sep 2002 01:23:54 -0400 +Message-ID: <3D895F60.4010902@mascari.com> +Date: Thu, 19 Sep 2002 01:23:45 -0400 +From: Mike Mascari +User-Agent: Mozilla/5.0 (Windows; U; WinNT4.0; en-US; rv:1.0.1) Gecko/20020823 Netscape/7.0 +X-Accept-Language: en-us, en +MIME-Version: 1.0 +To: Bruce Momjian +cc: PostgreSQL-development +Subject: Re: [HACKERS] Win32 rename()/unlink() questions +References: <200209190001.g8J01gG13849@candle.pha.pa.us> +Content-Type: text/plain; charset=us-ascii; format=flowed +Content-Transfer-Encoding: 7bit +X-MailScanner: Found to be clean +Status: OR + +Bruce Momjian wrote: +> I am working with several groups getting the Win32 port ready for 7.4 +> and I have a few questions: +> +> What is the standard workaround for the fact that rename() isn't atomic +> on Win32? Do we need to create our own locking around the +> reading/writing of files that are normally updated in place using +> rename()? + +Visual C++ comes with the source to Microsoft's C library: + +rename() calls MoveFile() which will error if: + +1. The target file exists +2. The source file is in use + +MoveFileEx() (not available on 95/98) can overwrite the target +file if it exists. The Apache APR portability library uses +MoveFileEx() to rename files if under NT/XP/2K vs. a sequence of : + +1. CreateFile() to test for target file existence +2. DeleteFile() to remove the target file +3. MoveFile() to rename the old file to new + +under Windows 95/98. Of course, some other process could create +the target file between 2 and 3, so their rename() would just +error out in that situation. I haven't tested it, but I recall +reading somewhere that MoveFileEx() has the ability to rename an +opened file. I'm 99% sure MoveFile() will fail if the source +file is open. + +> +> Second, when you unlink() a file on Win32, do applications continue +> accessing the old file contents if they had the file open before the +> unlink? +> + +unlink() just calls DeleteFile() which will error if: + +1. The target file is in use + +CreateFile() has the option: + +FILE_FLAG_DELETE_ON_CLOSE + +which might be able to be used to simulate traditional unlink() +behavior. + +Hope that helps, + +Mike Mascari +mascarm@mascari.com + + + + + + + + + + +From pgsql-hackers-owner+M29091@postgresql.org Thu Sep 19 01:24:54 2002 +Return-path: +Received: from postgresql.org (postgresql.org [64.49.215.8]) + by candle.pha.pa.us (8.11.6/8.10.1) with ESMTP id g8J5OqE18478 + for ; Thu, 19 Sep 2002 01:24:53 -0400 (EDT) +Received: from localhost (postgresql.org [64.49.215.8]) + by postgresql.org (Postfix) with ESMTP + id A5031476A31; Thu, 19 Sep 2002 01:24:52 -0400 (EDT) +Received: from postgresql.org (postgresql.org [64.49.215.8]) + by postgresql.org (Postfix) with SMTP + id F2ED047698F; Thu, 19 Sep 2002 01:24:50 -0400 (EDT) +Received: from localhost (postgresql.org [64.49.215.8]) + by postgresql.org (Postfix) with ESMTP id BA69E476086 + for ; Thu, 19 Sep 2002 01:24:47 -0400 (EDT) +Received: from corvette.mascari.com (dhcp065-024-158-068.columbus.rr.com [65.24.158.68]) + by postgresql.org (Postfix) with ESMTP id 56A2D475FE3 + for ; Thu, 19 Sep 2002 01:24:46 -0400 (EDT) +Received: from mascari.com (ferrari.mascari.com [192.168.2.1]) + by corvette.mascari.com (8.9.3/8.9.3) with ESMTP id BAA15293; + Thu, 19 Sep 2002 01:23:54 -0400 +Message-ID: <3D895F60.4010902@mascari.com> +Date: Thu, 19 Sep 2002 01:23:45 -0400 +From: Mike Mascari +User-Agent: Mozilla/5.0 (Windows; U; WinNT4.0; en-US; rv:1.0.1) Gecko/20020823 Netscape/7.0 +X-Accept-Language: en-us, en +MIME-Version: 1.0 +To: Bruce Momjian +cc: PostgreSQL-development +Subject: Re: [HACKERS] Win32 rename()/unlink() questions +References: <200209190001.g8J01gG13849@candle.pha.pa.us> +Content-Type: text/plain; charset=us-ascii; format=flowed +Content-Transfer-Encoding: 7bit +X-MailScanner: Found to be clean +X-Virus-Scanned: by AMaViS new-20020517 +Precedence: bulk +Sender: pgsql-hackers-owner@postgresql.org +X-Virus-Scanned: by AMaViS new-20020517 +Status: ORr + +Bruce Momjian wrote: +> I am working with several groups getting the Win32 port ready for 7.4 +> and I have a few questions: +> +> What is the standard workaround for the fact that rename() isn't atomic +> on Win32? Do we need to create our own locking around the +> reading/writing of files that are normally updated in place using +> rename()? + +Visual C++ comes with the source to Microsoft's C library: + +rename() calls MoveFile() which will error if: + +1. The target file exists +2. The source file is in use + +MoveFileEx() (not available on 95/98) can overwrite the target +file if it exists. The Apache APR portability library uses +MoveFileEx() to rename files if under NT/XP/2K vs. a sequence of : + +1. CreateFile() to test for target file existence +2. DeleteFile() to remove the target file +3. MoveFile() to rename the old file to new + +under Windows 95/98. Of course, some other process could create +the target file between 2 and 3, so their rename() would just +error out in that situation. I haven't tested it, but I recall +reading somewhere that MoveFileEx() has the ability to rename an +opened file. I'm 99% sure MoveFile() will fail if the source +file is open. + +> +> Second, when you unlink() a file on Win32, do applications continue +> accessing the old file contents if they had the file open before the +> unlink? +> + +unlink() just calls DeleteFile() which will error if: + +1. The target file is in use + +CreateFile() has the option: + +FILE_FLAG_DELETE_ON_CLOSE + +which might be able to be used to simulate traditional unlink() +behavior. + +Hope that helps, + +Mike Mascari +mascarm@mascari.com + + + + + + + + + + +---------------------------(end of broadcast)--------------------------- +TIP 6: Have you searched our list archives? + +http://archives.postgresql.org + +From pgsql-hackers-owner+M29090@postgresql.org Thu Sep 19 01:23:40 2002 +Return-path: +Received: from postgresql.org (postgresql.org [64.49.215.8]) + by candle.pha.pa.us (8.11.6/8.10.1) with ESMTP id g8J5NcE18313 + for ; Thu, 19 Sep 2002 01:23:38 -0400 (EDT) +Received: from localhost (postgresql.org [64.49.215.8]) + by postgresql.org (Postfix) with ESMTP + id 8B685476A38; Thu, 19 Sep 2002 01:23:39 -0400 (EDT) +Received: from postgresql.org (postgresql.org [64.49.215.8]) + by postgresql.org (Postfix) with SMTP + id 54C6E4769AA; Thu, 19 Sep 2002 01:23:37 -0400 (EDT) +Received: from localhost (postgresql.org [64.49.215.8]) + by postgresql.org (Postfix) with ESMTP id 47A9B4762E6 + for ; Thu, 19 Sep 2002 01:23:33 -0400 (EDT) +Received: from houston.familyhealth.com.au (unknown [203.59.48.253]) + by postgresql.org (Postfix) with ESMTP id 9D4C6476171 + for ; Thu, 19 Sep 2002 01:23:31 -0400 (EDT) +Received: (from root@localhost) + by houston.familyhealth.com.au (8.11.6/8.11.6) id g8J5NUJ42439 + for pgsql-hackers@postgresql.org; Thu, 19 Sep 2002 13:23:30 +0800 (WST) + (envelope-from chriskl@familyhealth.com.au) +Received: from mariner (mariner.internal [192.168.0.101]) + by houston.familyhealth.com.au (8.11.6/8.9.3) with SMTP id g8J5NSk42348; + Thu, 19 Sep 2002 13:23:28 +0800 (WST) +From: "Christopher Kings-Lynne" +To: "Ross J. Reedstrom" +cc: "PostgreSQL-development" +Subject: Re: [HACKERS] Win32 rename()/unlink() questions +Date: Thu, 19 Sep 2002 13:24:01 +0800 +Message-ID: +MIME-Version: 1.0 +Content-Type: text/plain; + charset="US-ASCII" +Content-Transfer-Encoding: 7bit +X-Priority: 3 (Normal) +X-MSMail-Priority: Normal +X-Mailer: Microsoft Outlook IMO, Build 9.0.2416 (9.0.2910.0) +In-Reply-To: <20020919050722.GC15352@rice.edu> +X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2600.0000 +Importance: Normal +X-scanner: scanned by Inflex 0.1.5c - (http://www.inflex.co.za/) +X-Virus-Scanned: by AMaViS new-20020517 +Precedence: bulk +Sender: pgsql-hackers-owner@postgresql.org +X-Virus-Scanned: by AMaViS new-20020517 +Status: OR + +> On Wed, Sep 18, 2002 at 08:01:42PM -0400, Bruce Momjian wrote: +> +> > Second, when you unlink() a file on Win32, do applications continue +> > accessing the old file contents if they had the file open before the +> > unlink? +> +> I'm pretty sure it errors with 'file in use'. Pretty ugly, huh? + +Yeah - the windows filesystem is pretty poor when it comes to multiuser +access. That's why even as administrator I cannot delete borked files and +people's profiles and stuff off our NT server - the files are always 'in +use'. Even if you kick all users off, reboot the machine, do whatever. +It's terrible. + +Chris + + +---------------------------(end of broadcast)--------------------------- +TIP 1: subscribe and unsubscribe commands go to majordomo@postgresql.org + +From pgsql-hackers-owner+M29092@postgresql.org Thu Sep 19 01:32:51 2002 +Return-path: +Received: from postgresql.org (postgresql.org [64.49.215.8]) + by candle.pha.pa.us (8.11.6/8.10.1) with ESMTP id g8J5WnE19160 + for ; Thu, 19 Sep 2002 01:32:50 -0400 (EDT) +Received: from localhost (postgresql.org [64.49.215.8]) + by postgresql.org (Postfix) with ESMTP + id A34DA476A7D; Thu, 19 Sep 2002 01:32:50 -0400 (EDT) +Received: from postgresql.org (postgresql.org [64.49.215.8]) + by postgresql.org (Postfix) with SMTP + id 80422476A62; Thu, 19 Sep 2002 01:32:48 -0400 (EDT) +Received: from localhost (postgresql.org [64.49.215.8]) + by postgresql.org (Postfix) with ESMTP id 496D1476A44 + for ; Thu, 19 Sep 2002 01:32:44 -0400 (EDT) +Received: from corvette.mascari.com (dhcp065-024-158-068.columbus.rr.com [65.24.158.68]) + by postgresql.org (Postfix) with ESMTP id 228C74769F6 + for ; Thu, 19 Sep 2002 01:32:43 -0400 (EDT) +Received: from mascari.com (ferrari.mascari.com [192.168.2.1]) + by corvette.mascari.com (8.9.3/8.9.3) with ESMTP id BAA15313; + Thu, 19 Sep 2002 01:31:28 -0400 +Message-ID: <3D896127.2070103@mascari.com> +Date: Thu, 19 Sep 2002 01:31:19 -0400 +From: Mike Mascari +User-Agent: Mozilla/5.0 (Windows; U; WinNT4.0; en-US; rv:1.0.1) Gecko/20020823 Netscape/7.0 +X-Accept-Language: en-us, en +MIME-Version: 1.0 +To: Christopher Kings-Lynne +cc: "Ross J. Reedstrom" , + PostgreSQL-development +Subject: Re: [HACKERS] Win32 rename()/unlink() questions +References: +Content-Type: text/plain; charset=us-ascii; format=flowed +Content-Transfer-Encoding: 7bit +X-MailScanner: Found to be clean +X-Virus-Scanned: by AMaViS new-20020517 +Precedence: bulk +Sender: pgsql-hackers-owner@postgresql.org +X-Virus-Scanned: by AMaViS new-20020517 +Status: OR + +Christopher Kings-Lynne wrote: +>>On Wed, Sep 18, 2002 at 08:01:42PM -0400, Bruce Momjian wrote: +>> +>> +>>>Second, when you unlink() a file on Win32, do applications continue +>>>accessing the old file contents if they had the file open before the +>>>unlink? +>> +>>I'm pretty sure it errors with 'file in use'. Pretty ugly, huh? +> +> +> Yeah - the windows filesystem is pretty poor when it comes to multiuser +> access. That's why even as administrator I cannot delete borked files and +> people's profiles and stuff off our NT server - the files are always 'in +> use'. Even if you kick all users off, reboot the machine, do whatever. +> It's terrible. + > + > Chris + > + +Yep. That's why often it requires rebooting to uninstall +software. How can the installer remove itself? Under Windows +95/98/ME, you have to manually add entries to WININIT.INI. With +Windows NT/XP/2K, MoveFileEx() with a NULL target and the +MOVEFILE_DELAY_UNTIL_REBOOT flag will add the appropriate +entries into the system registry so that the next time the +machine reboots it will remove the files specified. Its a real +pain and a real hack of an OS. + +Mike Mascari +mascarm@mascari.com + + + +---------------------------(end of broadcast)--------------------------- +TIP 1: subscribe and unsubscribe commands go to majordomo@postgresql.org + +From pgsql-hackers-owner+M29135@postgresql.org Thu Sep 19 16:26:02 2002 +Return-path: +Received: from postgresql.org (postgresql.org [64.49.215.8]) + by candle.pha.pa.us (8.11.6/8.10.1) with ESMTP id g8JKPvE10469 + for ; Thu, 19 Sep 2002 16:25:57 -0400 (EDT) +Received: from localhost (postgresql.org [64.49.215.8]) + by postgresql.org (Postfix) with ESMTP + id 55024476101; Thu, 19 Sep 2002 16:25:40 -0400 (EDT) +Received: from postgresql.org (postgresql.org [64.49.215.8]) + by postgresql.org (Postfix) with SMTP + id B87A6476A3F; Thu, 19 Sep 2002 16:25:34 -0400 (EDT) +Received: from localhost (postgresql.org [64.49.215.8]) + by postgresql.org (Postfix) with ESMTP id CC7F5476101 + for ; Thu, 19 Sep 2002 16:24:38 -0400 (EDT) +Received: from candle.pha.pa.us (momjian.navpoint.com [207.106.42.251]) + by postgresql.org (Postfix) with ESMTP id E04B8475AFF + for ; Thu, 19 Sep 2002 16:24:35 -0400 (EDT) +Received: (from pgman@localhost) + by candle.pha.pa.us (8.11.6/8.10.1) id g8JKO1g10337; + Thu, 19 Sep 2002 16:24:01 -0400 (EDT) +From: Bruce Momjian +Message-ID: <200209192024.g8JKO1g10337@candle.pha.pa.us> +Subject: Re: [HACKERS] Win32 rename()/unlink() questions +In-Reply-To: <3D895F60.4010902@mascari.com> +To: Mike Mascari +Date: Thu, 19 Sep 2002 16:24:01 -0400 (EDT) +cc: PostgreSQL-development +X-Mailer: ELM [version 2.4ME+ PL99 (25)] +MIME-Version: 1.0 +Content-Transfer-Encoding: 7bit +Content-Type: text/plain; charset=US-ASCII +X-Virus-Scanned: by AMaViS new-20020517 +Precedence: bulk +Sender: pgsql-hackers-owner@postgresql.org +X-Virus-Scanned: by AMaViS new-20020517 +Status: ORr + +Mike Mascari wrote: +> Bruce Momjian wrote: +> > I am working with several groups getting the Win32 port ready for 7.4 +> > and I have a few questions: +> > +> > What is the standard workaround for the fact that rename() isn't atomic +> > on Win32? Do we need to create our own locking around the +> > reading/writing of files that are normally updated in place using +> > rename()? +> +> Visual C++ comes with the source to Microsoft's C library: +> +> rename() calls MoveFile() which will error if: +> +> 1. The target file exists +> 2. The source file is in use +> +> MoveFileEx() (not available on 95/98) can overwrite the target +> file if it exists. The Apache APR portability library uses +> MoveFileEx() to rename files if under NT/XP/2K vs. a sequence of : +> +> 1. CreateFile() to test for target file existence +> 2. DeleteFile() to remove the target file +> 3. MoveFile() to rename the old file to new +> +> under Windows 95/98. Of course, some other process could create +> the target file between 2 and 3, so their rename() would just +> error out in that situation. I haven't tested it, but I recall +> reading somewhere that MoveFileEx() has the ability to rename an +> opened file. I'm 99% sure MoveFile() will fail if the source +> file is open. + +OK, I downloaded APR and see in apr_file_rename(): + + if (MoveFileEx(frompath, topath, MOVEFILE_REPLACE_EXISTING | + MOVEFILE_COPY_ALLOWED)) + + +Looking at the entire APR function, they have lots of tests so it works +on Win9X and wide characters. I think we will just use the APR as a +guide in implementing the things we need. I think MoveFileEx() is the +proper way to go; any other solution requires loop tests for rename. + +I see the MoveFileEx manual page at: + + http://msdn.microsoft.com/library/default.asp?url=/library/en-us/fileio/base/movefile.asp + +> > Second, when you unlink() a file on Win32, do applications continue +> > accessing the old file contents if they had the file open before the +> > unlink? +> > +> +> unlink() just calls DeleteFile() which will error if: +> +> 1. The target file is in use +> +> CreateFile() has the option: +> +> FILE_FLAG_DELETE_ON_CLOSE +> +> which might be able to be used to simulate traditional unlink() +> behavior. + +No, that flag isn't going to help us. I wonder what MoveFileEx does if +the target file exists _and_ is open by another user? I don't see any +loop in that Win32 rename() routine, and I looked at the Unix version of +apr_file_rename and its just a straight rename() call. + +-- + Bruce Momjian | http://candle.pha.pa.us + pgman@candle.pha.pa.us | (610) 359-1001 + + If your life is a hard drive, | 13 Roberts Road + + Christ can be your backup. | Newtown Square, Pennsylvania 19073 + +---------------------------(end of broadcast)--------------------------- +TIP 3: if posting/reading through Usenet, please send an appropriate +subscribe-nomail command to majordomo@postgresql.org so that your +message can get through to the mailing list cleanly + +From pgman Thu Sep 19 22:50:41 2002 +Return-path: +Received: (from pgman@localhost) + by candle.pha.pa.us (8.11.6/8.10.1) id g8K2ofr29042; + Thu, 19 Sep 2002 22:50:41 -0400 (EDT) +From: Bruce Momjian +Message-ID: <200209200250.g8K2ofr29042@candle.pha.pa.us> +Subject: Re: [HACKERS] Win32 rename()/unlink() questions +In-Reply-To: <200209192024.g8JKO1g10337@candle.pha.pa.us> +To: Bruce Momjian +Date: Thu, 19 Sep 2002 22:50:41 -0400 (EDT) +cc: Mike Mascari , + PostgreSQL-development +X-Mailer: ELM [version 2.4ME+ PL99 (25)] +MIME-Version: 1.0 +Content-Transfer-Encoding: 7bit +Content-Type: text/plain; charset=US-ASCII +Status: OR + +Bruce Momjian wrote: +> > > Second, when you unlink() a file on Win32, do applications continue +> > > accessing the old file contents if they had the file open before the +> > > unlink? +> > > +> > +> > unlink() just calls DeleteFile() which will error if: +> > +> > 1. The target file is in use +> > +> > CreateFile() has the option: +> > +> > FILE_FLAG_DELETE_ON_CLOSE +> > +> > which might be able to be used to simulate traditional unlink() +> > behavior. +> +> No, that flag isn't going to help us. I wonder what MoveFileEx does if +> the target file exists _and_ is open by another user? I don't see any +> loop in that Win32 rename() routine, and I looked at the Unix version of +> apr_file_rename and its just a straight rename() call. + +This says that if the target is in use, it is overwritten: + + http://support.microsoft.com/default.aspx?scid=KB;EN-US;q140570& + +While I think that is good news, does it open the problem of other +readers reading partial updates to the file and therefore seeing +garbage. Not sure how to handle that, nor am I even sure how I would +test it. + +-- + Bruce Momjian | http://candle.pha.pa.us + pgman@candle.pha.pa.us | (610) 359-1001 + + If your life is a hard drive, | 13 Roberts Road + + Christ can be your backup. | Newtown Square, Pennsylvania 19073 + +From pgsql-hackers-owner+M29166@postgresql.org Thu Sep 19 22:52:08 2002 +Return-path: +Received: from postgresql.org (postgresql.org [64.49.215.8]) + by candle.pha.pa.us (8.11.6/8.10.1) with ESMTP id g8K2q7E29312 + for ; Thu, 19 Sep 2002 22:52:07 -0400 (EDT) +Received: from localhost (postgresql.org [64.49.215.8]) + by postgresql.org (Postfix) with ESMTP + id 5B1CE47620D; Thu, 19 Sep 2002 22:51:36 -0400 (EDT) +Received: from postgresql.org (postgresql.org [64.49.215.8]) + by postgresql.org (Postfix) with SMTP + id 6CC8F47651C; Thu, 19 Sep 2002 22:51:13 -0400 (EDT) +Received: from localhost (postgresql.org [64.49.215.8]) + by postgresql.org (Postfix) with ESMTP id 77E1F476476 + for ; Thu, 19 Sep 2002 22:50:57 -0400 (EDT) +Received: from candle.pha.pa.us (momjian.navpoint.com [207.106.42.251]) + by postgresql.org (Postfix) with ESMTP id 8CF61476459 + for ; Thu, 19 Sep 2002 22:50:55 -0400 (EDT) +Received: (from pgman@localhost) + by candle.pha.pa.us (8.11.6/8.10.1) id g8K2ofr29042; + Thu, 19 Sep 2002 22:50:41 -0400 (EDT) +From: Bruce Momjian +Message-ID: <200209200250.g8K2ofr29042@candle.pha.pa.us> +Subject: Re: [HACKERS] Win32 rename()/unlink() questions +In-Reply-To: <200209192024.g8JKO1g10337@candle.pha.pa.us> +To: Bruce Momjian +Date: Thu, 19 Sep 2002 22:50:41 -0400 (EDT) +cc: Mike Mascari , + PostgreSQL-development +X-Mailer: ELM [version 2.4ME+ PL99 (25)] +MIME-Version: 1.0 +Content-Transfer-Encoding: 7bit +Content-Type: text/plain; charset=US-ASCII +X-Virus-Scanned: by AMaViS new-20020517 +Precedence: bulk +Sender: pgsql-hackers-owner@postgresql.org +X-Virus-Scanned: by AMaViS new-20020517 +Status: OR + +Bruce Momjian wrote: +> > > Second, when you unlink() a file on Win32, do applications continue +> > > accessing the old file contents if they had the file open before the +> > > unlink? +> > > +> > +> > unlink() just calls DeleteFile() which will error if: +> > +> > 1. The target file is in use +> > +> > CreateFile() has the option: +> > +> > FILE_FLAG_DELETE_ON_CLOSE +> > +> > which might be able to be used to simulate traditional unlink() +> > behavior. +> +> No, that flag isn't going to help us. I wonder what MoveFileEx does if +> the target file exists _and_ is open by another user? I don't see any +> loop in that Win32 rename() routine, and I looked at the Unix version of +> apr_file_rename and its just a straight rename() call. + +This says that if the target is in use, it is overwritten: + + http://support.microsoft.com/default.aspx?scid=KB;EN-US;q140570& + +While I think that is good news, does it open the problem of other +readers reading partial updates to the file and therefore seeing +garbage. Not sure how to handle that, nor am I even sure how I would +test it. + +-- + Bruce Momjian | http://candle.pha.pa.us + pgman@candle.pha.pa.us | (610) 359-1001 + + If your life is a hard drive, | 13 Roberts Road + + Christ can be your backup. | Newtown Square, Pennsylvania 19073 + +---------------------------(end of broadcast)--------------------------- +TIP 1: subscribe and unsubscribe commands go to majordomo@postgresql.org + +From mascarm@mascari.com Fri Sep 20 00:02:33 2002 +Return-path: +Received: from corvette.mascari.com (dhcp065-024-158-068.columbus.rr.com [65.24.158.68]) + by candle.pha.pa.us (8.11.6/8.10.1) with ESMTP id g8K42SE12294 + for ; Fri, 20 Sep 2002 00:02:31 -0400 (EDT) +Received: from mascari.com (ferrari.mascari.com [192.168.2.1]) + by corvette.mascari.com (8.9.3/8.9.3) with ESMTP id AAA18322; + Fri, 20 Sep 2002 00:01:34 -0400 +Message-ID: <3D8A9DAD.5040500@mascari.com> +Date: Fri, 20 Sep 2002 00:01:49 -0400 +From: Mike Mascari +User-Agent: Mozilla/5.0 (Windows; U; WinNT4.0; en-US; rv:1.0.1) Gecko/20020823 Netscape/7.0 +X-Accept-Language: en-us, en +MIME-Version: 1.0 +To: Bruce Momjian +cc: PostgreSQL-development +Subject: Re: [HACKERS] Win32 rename()/unlink() questions +References: <200209200250.g8K2ofr29042@candle.pha.pa.us> +Content-Type: text/plain; charset=us-ascii; format=flowed +Content-Transfer-Encoding: 7bit +X-MailScanner: Found to be clean +Status: ORr + +Bruce Momjian wrote: +> Bruce Momjian wrote: +>>> +>>>unlink() just calls DeleteFile() which will error if: +>>> +>>>1. The target file is in use +>>> +>>>CreateFile() has the option: +>>> +>>>FILE_FLAG_DELETE_ON_CLOSE +>>> +>>>which might be able to be used to simulate traditional unlink() +>>>behavior. +>> +>>No, that flag isn't going to help us. I wonder what MoveFileEx does if +>>the target file exists _and_ is open by another user? I don't see any +>>loop in that Win32 rename() routine, and I looked at the Unix version of +>>apr_file_rename and its just a straight rename() call. +> +> +> This says that if the target is in use, it is overwritten: +> +> http://support.microsoft.com/default.aspx?scid=KB;EN-US;q140570& + +I read the article and did not come away with that conclusion. +The article describes using the MOVEFILE_DELAY_UNTIL_REBOOT +flag, which was created for the express purpose of allowing a +SETUP.EXE to remove itself, or rather tell Windows to remove it +on the next reboot. Also, if you want the Win32 port to run in +95/98/ME, you can't rely on MoveFileEx(), you have to use +MoveFile(). + +I will do some testing with concurrency and let you know. But +don't get your hopes up. This is one of the many advantages that +TABLESPACEs have when more than one relation is stored in a +single DATAFILE. There was Oracle for MS-DOS, after all.. + +Mike Mascari +mascarm@mascari.com + + + + + +From pgsql-hackers-owner+M29177@postgresql.org Fri Sep 20 00:06:31 2002 +Return-path: +Received: from postgresql.org (postgresql.org [64.49.215.8]) + by candle.pha.pa.us (8.11.6/8.10.1) with ESMTP id g8K46TE12770 + for ; Fri, 20 Sep 2002 00:06:29 -0400 (EDT) +Received: from localhost (postgresql.org [64.49.215.8]) + by postgresql.org (Postfix) with ESMTP + id 44057476CF8; Fri, 20 Sep 2002 00:06:24 -0400 (EDT) +Received: from postgresql.org (postgresql.org [64.49.215.8]) + by postgresql.org (Postfix) with SMTP + id A0C78476C00; Fri, 20 Sep 2002 00:06:22 -0400 (EDT) +Received: from localhost (postgresql.org [64.49.215.8]) + by postgresql.org (Postfix) with ESMTP id 5AB4E476D1C + for ; Fri, 20 Sep 2002 00:05:57 -0400 (EDT) +Received: from candle.pha.pa.us (momjian.navpoint.com [207.106.42.251]) + by postgresql.org (Postfix) with ESMTP id 990B9476D38 + for ; Fri, 20 Sep 2002 00:05:55 -0400 (EDT) +Received: (from pgman@localhost) + by candle.pha.pa.us (8.11.6/8.10.1) id g8K45RV12655; + Fri, 20 Sep 2002 00:05:27 -0400 (EDT) +From: Bruce Momjian +Message-ID: <200209200405.g8K45RV12655@candle.pha.pa.us> +Subject: Re: [HACKERS] Win32 rename()/unlink() questions +In-Reply-To: <3D8A9DAD.5040500@mascari.com> +To: Mike Mascari +Date: Fri, 20 Sep 2002 00:05:27 -0400 (EDT) +cc: PostgreSQL-development +X-Mailer: ELM [version 2.4ME+ PL99 (25)] +MIME-Version: 1.0 +Content-Transfer-Encoding: 7bit +Content-Type: text/plain; charset=US-ASCII +X-Virus-Scanned: by AMaViS new-20020517 +Precedence: bulk +Sender: pgsql-hackers-owner@postgresql.org +X-Virus-Scanned: by AMaViS new-20020517 +Status: OR + +Mike Mascari wrote: +> I read the article and did not come away with that conclusion. +> The article describes using the MOVEFILE_DELAY_UNTIL_REBOOT +> flag, which was created for the express purpose of allowing a +> SETUP.EXE to remove itself, or rather tell Windows to remove it +> on the next reboot. Also, if you want the Win32 port to run in +> 95/98/ME, you can't rely on MoveFileEx(), you have to use +> MoveFile(). +> +> I will do some testing with concurrency and let you know. But +> don't get your hopes up. This is one of the many advantages that +> TABLESPACEs have when more than one relation is stored in a +> single DATAFILE. There was Oracle for MS-DOS, after all.. + +I was focusing on handling of pg_pwd and other config file that are +written by various backend while other backends are reading them. The +actual data files should be OK because we have an exclusive lock when we +are adding/removing them. + +-- + Bruce Momjian | http://candle.pha.pa.us + pgman@candle.pha.pa.us | (610) 359-1001 + + If your life is a hard drive, | 13 Roberts Road + + Christ can be your backup. | Newtown Square, Pennsylvania 19073 + +---------------------------(end of broadcast)--------------------------- +TIP 5: Have you checked our extensive FAQ? + +http://www.postgresql.org/users-lounge/docs/faq.html + +From pgsql-hackers-owner+M29179@postgresql.org Fri Sep 20 00:33:22 2002 +Return-path: +Received: from postgresql.org (postgresql.org [64.49.215.8]) + by candle.pha.pa.us (8.11.6/8.10.1) with ESMTP id g8K4XKE14843 + for ; Fri, 20 Sep 2002 00:33:20 -0400 (EDT) +Received: from localhost (postgresql.org [64.49.215.8]) + by postgresql.org (Postfix) with ESMTP + id EB433476D5B; Fri, 20 Sep 2002 00:32:25 -0400 (EDT) +Received: from postgresql.org (postgresql.org [64.49.215.8]) + by postgresql.org (Postfix) with SMTP + id 2ED3A476D4E; Fri, 20 Sep 2002 00:32:24 -0400 (EDT) +Received: from localhost (postgresql.org [64.49.215.8]) + by postgresql.org (Postfix) with ESMTP id 43723476994 + for ; Fri, 20 Sep 2002 00:32:20 -0400 (EDT) +Received: from corvette.mascari.com (dhcp065-024-158-068.columbus.rr.com [65.24.158.68]) + by postgresql.org (Postfix) with ESMTP id A66C6476883 + for ; Fri, 20 Sep 2002 00:32:18 -0400 (EDT) +Received: from mascari.com (ferrari.mascari.com [192.168.2.1]) + by corvette.mascari.com (8.9.3/8.9.3) with ESMTP id AAA18391; + Fri, 20 Sep 2002 00:31:31 -0400 +Message-ID: <3D8AA4B2.8090507@mascari.com> +Date: Fri, 20 Sep 2002 00:31:46 -0400 +From: Mike Mascari +User-Agent: Mozilla/5.0 (Windows; U; WinNT4.0; en-US; rv:1.0.1) Gecko/20020823 Netscape/7.0 +X-Accept-Language: en-us, en +MIME-Version: 1.0 +To: Bruce Momjian +cc: PostgreSQL-development +Subject: Re: [HACKERS] Win32 rename()/unlink() questions +References: <200209200405.g8K45RV12655@candle.pha.pa.us> +Content-Type: text/plain; charset=us-ascii; format=flowed +Content-Transfer-Encoding: 7bit +X-MailScanner: Found to be clean +X-Virus-Scanned: by AMaViS new-20020517 +Precedence: bulk +Sender: pgsql-hackers-owner@postgresql.org +X-Virus-Scanned: by AMaViS new-20020517 +Status: OR + +Bruce Momjian wrote: +> Mike Mascari wrote: +> +>>I will do some testing with concurrency and let you know. But +>>don't get your hopes up. This is one of the many advantages that +>>TABLESPACEs have when more than one relation is stored in a +>>single DATAFILE. There was Oracle for MS-DOS, after all.. +> +> +> I was focusing on handling of pg_pwd and other config file that are +> written by various backend while other backends are reading them. The +> actual data files should be OK because we have an exclusive lock when we +> are adding/removing them. +> + +OK. So you want to test: + +1. Process 1 opens "foo" +2. Process 2 opens "foo" +3. Process 1 renames "foo" to "bar" +4. Process 2 can safely read from its open file handle + +Is that what you want tested? I have a small Win32 app ready to +test. Just let me know the scenarios... + +Mike Mascari +mascarm@mascari.com + + + + + +---------------------------(end of broadcast)--------------------------- +TIP 1: subscribe and unsubscribe commands go to majordomo@postgresql.org + +From mascarm@mascari.com Fri Sep 20 01:01:37 2002 +Return-path: +Received: from corvette.mascari.com (dhcp065-024-158-068.columbus.rr.com [65.24.158.68]) + by candle.pha.pa.us (8.11.6/8.10.1) with ESMTP id g8K51WE17352 + for ; Fri, 20 Sep 2002 01:01:35 -0400 (EDT) +Received: from mascari.com (ferrari.mascari.com [192.168.2.1]) + by corvette.mascari.com (8.9.3/8.9.3) with ESMTP id BAA18603; + Fri, 20 Sep 2002 01:00:49 -0400 +Message-ID: <3D8AAB8F.8010001@mascari.com> +Date: Fri, 20 Sep 2002 01:01:03 -0400 +From: Mike Mascari +User-Agent: Mozilla/5.0 (Windows; U; WinNT4.0; en-US; rv:1.0.1) Gecko/20020823 Netscape/7.0 +X-Accept-Language: en-us, en +MIME-Version: 1.0 +To: Mike Mascari +cc: Bruce Momjian , + PostgreSQL-development + +Subject: Re: [HACKERS] Win32 rename()/unlink() questions +References: <200209200405.g8K45RV12655@candle.pha.pa.us> <3D8AA4B2.8090507@mascari.com> +Content-Type: text/plain; charset=us-ascii; format=flowed +Content-Transfer-Encoding: 7bit +X-MailScanner: Found to be clean +Status: ORr + +Mike Mascari wrote: +> Bruce Momjian wrote: +> +>> Mike Mascari wrote: +>> +>>> I will do some testing with concurrency and let you know. But don't +>>> get your hopes up. This is one of the many advantages that +>>> TABLESPACEs have when more than one relation is stored in a single +>>> DATAFILE. There was Oracle for MS-DOS, after all.. +>> +>> +>> +>> I was focusing on handling of pg_pwd and other config file that are +>> written by various backend while other backends are reading them. The +>> actual data files should be OK because we have an exclusive lock when we +>> are adding/removing them. +>> +> +> OK. So you want to test: +> +> 1. Process 1 opens "foo" +> 2. Process 2 opens "foo" +> 3. Process 1 renames "foo" to "bar" +> 4. Process 2 can safely read from its open file handle + +Actually, looking at the pg_pwd code, you want to determine a +way for: + +1. Process 1 opens "foo" +2. Process 2 opens "foo" +3. Process 1 creates "bar" +4. Process 1 renames "bar" to "foo" +5. Process 2 can continue to read data from the open file handle +and get the original "foo" data. + +Is that correct? + +Mike Mascari +mascarm@mascari.com + + +From pgsql-hackers-owner+M29180@postgresql.org Fri Sep 20 01:02:47 2002 +Return-path: +Received: from postgresql.org (postgresql.org [64.49.215.8]) + by candle.pha.pa.us (8.11.6/8.10.1) with ESMTP id g8K52kE17470 + for ; Fri, 20 Sep 2002 01:02:46 -0400 (EDT) +Received: from localhost (postgresql.org [64.49.215.8]) + by postgresql.org (Postfix) with ESMTP + id A4AB5476D73; Fri, 20 Sep 2002 01:02:29 -0400 (EDT) +Received: from postgresql.org (postgresql.org [64.49.215.8]) + by postgresql.org (Postfix) with SMTP + id 35B61476D76; Fri, 20 Sep 2002 01:02:21 -0400 (EDT) +Received: from localhost (postgresql.org [64.49.215.8]) + by postgresql.org (Postfix) with ESMTP id 4D3D14760AB + for ; Fri, 20 Sep 2002 01:01:55 -0400 (EDT) +Received: from corvette.mascari.com (dhcp065-024-158-068.columbus.rr.com [65.24.158.68]) + by postgresql.org (Postfix) with ESMTP id D259E475EAA + for ; Fri, 20 Sep 2002 01:01:53 -0400 (EDT) +Received: from mascari.com (ferrari.mascari.com [192.168.2.1]) + by corvette.mascari.com (8.9.3/8.9.3) with ESMTP id BAA18603; + Fri, 20 Sep 2002 01:00:49 -0400 +Message-ID: <3D8AAB8F.8010001@mascari.com> +Date: Fri, 20 Sep 2002 01:01:03 -0400 +From: Mike Mascari +User-Agent: Mozilla/5.0 (Windows; U; WinNT4.0; en-US; rv:1.0.1) Gecko/20020823 Netscape/7.0 +X-Accept-Language: en-us, en +MIME-Version: 1.0 +To: Mike Mascari +cc: Bruce Momjian , + PostgreSQL-development +Subject: Re: [HACKERS] Win32 rename()/unlink() questions +References: <200209200405.g8K45RV12655@candle.pha.pa.us> <3D8AA4B2.8090507@mascari.com> +Content-Type: text/plain; charset=us-ascii; format=flowed +Content-Transfer-Encoding: 7bit +X-MailScanner: Found to be clean +X-Virus-Scanned: by AMaViS new-20020517 +Precedence: bulk +Sender: pgsql-hackers-owner@postgresql.org +X-Virus-Scanned: by AMaViS new-20020517 +Status: OR + +Mike Mascari wrote: +> Bruce Momjian wrote: +> +>> Mike Mascari wrote: +>> +>>> I will do some testing with concurrency and let you know. But don't +>>> get your hopes up. This is one of the many advantages that +>>> TABLESPACEs have when more than one relation is stored in a single +>>> DATAFILE. There was Oracle for MS-DOS, after all.. +>> +>> +>> +>> I was focusing on handling of pg_pwd and other config file that are +>> written by various backend while other backends are reading them. The +>> actual data files should be OK because we have an exclusive lock when we +>> are adding/removing them. +>> +> +> OK. So you want to test: +> +> 1. Process 1 opens "foo" +> 2. Process 2 opens "foo" +> 3. Process 1 renames "foo" to "bar" +> 4. Process 2 can safely read from its open file handle + +Actually, looking at the pg_pwd code, you want to determine a +way for: + +1. Process 1 opens "foo" +2. Process 2 opens "foo" +3. Process 1 creates "bar" +4. Process 1 renames "bar" to "foo" +5. Process 2 can continue to read data from the open file handle +and get the original "foo" data. + +Is that correct? + +Mike Mascari +mascarm@mascari.com + + +---------------------------(end of broadcast)--------------------------- +TIP 5: Have you checked our extensive FAQ? + +http://www.postgresql.org/users-lounge/docs/faq.html + +From pgsql-hackers-owner+M29181@postgresql.org Fri Sep 20 01:30:05 2002 +Return-path: +Received: from postgresql.org (postgresql.org [64.49.215.8]) + by candle.pha.pa.us (8.11.6/8.10.1) with ESMTP id g8K5U2E20514 + for ; Fri, 20 Sep 2002 01:30:03 -0400 (EDT) +Received: from localhost (postgresql.org [64.49.215.8]) + by postgresql.org (Postfix) with ESMTP + id CDCF2476D1D; Fri, 20 Sep 2002 01:29:59 -0400 (EDT) +Received: from postgresql.org (postgresql.org [64.49.215.8]) + by postgresql.org (Postfix) with SMTP + id CB1CB476C00; Fri, 20 Sep 2002 01:29:57 -0400 (EDT) +Received: from localhost (postgresql.org [64.49.215.8]) + by postgresql.org (Postfix) with ESMTP id D9372475FC6 + for ; Fri, 20 Sep 2002 01:29:52 -0400 (EDT) +Received: from candle.pha.pa.us (momjian.navpoint.com [207.106.42.251]) + by postgresql.org (Postfix) with ESMTP id 21835475BF9 + for ; Fri, 20 Sep 2002 01:29:51 -0400 (EDT) +Received: (from pgman@localhost) + by candle.pha.pa.us (8.11.6/8.10.1) id g8K5TYr20440; + Fri, 20 Sep 2002 01:29:34 -0400 (EDT) +From: Bruce Momjian +Message-ID: <200209200529.g8K5TYr20440@candle.pha.pa.us> +Subject: Re: [HACKERS] Win32 rename()/unlink() questions +In-Reply-To: <3D8AAB8F.8010001@mascari.com> +To: Mike Mascari +Date: Fri, 20 Sep 2002 01:29:33 -0400 (EDT) +cc: PostgreSQL-development +X-Mailer: ELM [version 2.4ME+ PL99 (25)] +MIME-Version: 1.0 +Content-Transfer-Encoding: 7bit +Content-Type: text/plain; charset=US-ASCII +X-Virus-Scanned: by AMaViS new-20020517 +Precedence: bulk +Sender: pgsql-hackers-owner@postgresql.org +X-Virus-Scanned: by AMaViS new-20020517 +Status: OR + +Mike Mascari wrote: +> Actually, looking at the pg_pwd code, you want to determine a +> way for: +> +> 1. Process 1 opens "foo" +> 2. Process 2 opens "foo" +> 3. Process 1 creates "bar" +> 4. Process 1 renames "bar" to "foo" +> 5. Process 2 can continue to read data from the open file handle +> and get the original "foo" data. + +Yep, that's it. + +-- + Bruce Momjian | http://candle.pha.pa.us + pgman@candle.pha.pa.us | (610) 359-1001 + + If your life is a hard drive, | 13 Roberts Road + + Christ can be your backup. | Newtown Square, Pennsylvania 19073 + +---------------------------(end of broadcast)--------------------------- +TIP 2: you can get off all lists at once with the unregister command + (send "unregister YourEmailAddressHere" to majordomo@postgresql.org) + +From pgsql-hackers-owner+M29182@postgresql.org Fri Sep 20 01:36:21 2002 +Return-path: +Received: from postgresql.org (postgresql.org [64.49.215.8]) + by candle.pha.pa.us (8.11.6/8.10.1) with ESMTP id g8K5aJE21658 + for ; Fri, 20 Sep 2002 01:36:20 -0400 (EDT) +Received: from localhost (postgresql.org [64.49.215.8]) + by postgresql.org (Postfix) with ESMTP + id 926CA4764F2; Fri, 20 Sep 2002 01:36:20 -0400 (EDT) +Received: from postgresql.org (postgresql.org [64.49.215.8]) + by postgresql.org (Postfix) with SMTP + id 8F0E4475EEE; Fri, 20 Sep 2002 01:36:18 -0400 (EDT) +Received: from localhost (postgresql.org [64.49.215.8]) + by postgresql.org (Postfix) with ESMTP id 3A84C4769DA + for ; Fri, 20 Sep 2002 01:36:14 -0400 (EDT) +Received: from corvette.mascari.com (dhcp065-024-158-068.columbus.rr.com [65.24.158.68]) + by postgresql.org (Postfix) with ESMTP id E8DAA476413 + for ; Fri, 20 Sep 2002 01:36:12 -0400 (EDT) +Received: from mascari.com (ferrari.mascari.com [192.168.2.1]) + by corvette.mascari.com (8.9.3/8.9.3) with ESMTP id BAA18679; + Fri, 20 Sep 2002 01:35:09 -0400 +Message-ID: <3D8AB39B.80708@mascari.com> +Date: Fri, 20 Sep 2002 01:35:23 -0400 +From: Mike Mascari +User-Agent: Mozilla/5.0 (Windows; U; WinNT4.0; en-US; rv:1.0.1) Gecko/20020823 Netscape/7.0 +X-Accept-Language: en-us, en +MIME-Version: 1.0 +To: Bruce Momjian +cc: PostgreSQL-development +Subject: Re: [HACKERS] Win32 rename()/unlink() questions +References: <200209200529.g8K5TYr20440@candle.pha.pa.us> +Content-Type: text/plain; charset=us-ascii; format=flowed +Content-Transfer-Encoding: 7bit +X-MailScanner: Found to be clean +X-Virus-Scanned: by AMaViS new-20020517 +Precedence: bulk +Sender: pgsql-hackers-owner@postgresql.org +X-Virus-Scanned: by AMaViS new-20020517 +Status: OR + +Bruce Momjian wrote: +> Mike Mascari wrote: +> +>>Actually, looking at the pg_pwd code, you want to determine a +>>way for: +>> +>>1. Process 1 opens "foo" +>>2. Process 2 opens "foo" +>>3. Process 1 creates "bar" +>>4. Process 1 renames "bar" to "foo" +>>5. Process 2 can continue to read data from the open file handle +>>and get the original "foo" data. +> +> +> Yep, that's it. +> + +So far, MoveFileEx("foo", "bar", MOVEFILE_REPLACE_EXISTING) +returns "Access Denied" when Process 1 attempts the rename. But +I'm continuing to investigate the possibilities... + +Mike Mascari +mascarm@mascari.com + + + + + +---------------------------(end of broadcast)--------------------------- +TIP 4: Don't 'kill -9' the postmaster + +From sszabo@megazone23.bigpanda.com Fri Sep 20 01:50:39 2002 +Return-path: +Received: from megazone.bigpanda.com (megazone.bigpanda.com [63.150.15.178]) + by candle.pha.pa.us (8.11.6/8.10.1) with ESMTP id g8K5oaE22843 + for ; Fri, 20 Sep 2002 01:50:38 -0400 (EDT) +Received: by megazone.bigpanda.com (Postfix, from userid 1001) + id 709D1D61E; Thu, 19 Sep 2002 22:50:36 -0700 (PDT) +Received: from localhost (localhost [127.0.0.1]) + by megazone.bigpanda.com (Postfix) with ESMTP + id 624665C02; Thu, 19 Sep 2002 22:50:36 -0700 (PDT) +Date: Thu, 19 Sep 2002 22:50:36 -0700 (PDT) +From: Stephan Szabo +To: Mike Mascari +cc: Bruce Momjian , + PostgreSQL-development +Subject: Re: [HACKERS] Win32 rename()/unlink() questions +In-Reply-To: <3D8AB39B.80708@mascari.com> +Message-ID: <20020919224718.H36366-100000@megazone23.bigpanda.com> +MIME-Version: 1.0 +Content-Type: TEXT/PLAIN; charset=US-ASCII +Status: OR + + +On Fri, 20 Sep 2002, Mike Mascari wrote: + +> Bruce Momjian wrote: +> > Mike Mascari wrote: +> > +> >>Actually, looking at the pg_pwd code, you want to determine a +> >>way for: +> >> +> >>1. Process 1 opens "foo" +> >>2. Process 2 opens "foo" +> >>3. Process 1 creates "bar" +> >>4. Process 1 renames "bar" to "foo" +> >>5. Process 2 can continue to read data from the open file handle +> >>and get the original "foo" data. +> > +> > +> > Yep, that's it. +> > +> +> So far, MoveFileEx("foo", "bar", MOVEFILE_REPLACE_EXISTING) +> returns "Access Denied" when Process 1 attempts the rename. But +> I'm continuing to investigate the possibilities... + +Does a sequence like +Process 1 opens "foo" +Process 2 opens "foo" +Process 1 creates "bar" +Process 1 renames "foo" to + - where something is generated to not overlap an existing file +Process 1 renames "bar" to "foo" +Process 2 continues reading +let you do the replace and keep reading (at the penalty that +you've now got to have a way to know when to remove the +various s) + + + +From pgsql-hackers-owner+M29183@postgresql.org Fri Sep 20 01:50:47 2002 +Return-path: +Received: from postgresql.org (postgresql.org [64.49.215.8]) + by candle.pha.pa.us (8.11.6/8.10.1) with ESMTP id g8K5ojE22893 + for ; Fri, 20 Sep 2002 01:50:46 -0400 (EDT) +Received: from localhost (postgresql.org [64.49.215.8]) + by postgresql.org (Postfix) with ESMTP + id A8A20476D3B; Fri, 20 Sep 2002 01:50:46 -0400 (EDT) +Received: from postgresql.org (postgresql.org [64.49.215.8]) + by postgresql.org (Postfix) with SMTP + id 70EBC476B1F; Fri, 20 Sep 2002 01:50:44 -0400 (EDT) +Received: from localhost (postgresql.org [64.49.215.8]) + by postgresql.org (Postfix) with ESMTP id 8B227475EEE + for ; Fri, 20 Sep 2002 01:50:40 -0400 (EDT) +Received: from megazone.bigpanda.com (megazone.bigpanda.com [63.150.15.178]) + by postgresql.org (Postfix) with ESMTP id AE58D476D2C + for ; Fri, 20 Sep 2002 01:50:36 -0400 (EDT) +Received: by megazone.bigpanda.com (Postfix, from userid 1001) + id 709D1D61E; Thu, 19 Sep 2002 22:50:36 -0700 (PDT) +Received: from localhost (localhost [127.0.0.1]) + by megazone.bigpanda.com (Postfix) with ESMTP + id 624665C02; Thu, 19 Sep 2002 22:50:36 -0700 (PDT) +Date: Thu, 19 Sep 2002 22:50:36 -0700 (PDT) +From: Stephan Szabo +To: Mike Mascari +cc: Bruce Momjian , + PostgreSQL-development +Subject: Re: [HACKERS] Win32 rename()/unlink() questions +In-Reply-To: <3D8AB39B.80708@mascari.com> +Message-ID: <20020919224718.H36366-100000@megazone23.bigpanda.com> +MIME-Version: 1.0 +Content-Type: TEXT/PLAIN; charset=US-ASCII +X-Virus-Scanned: by AMaViS new-20020517 +Precedence: bulk +Sender: pgsql-hackers-owner@postgresql.org +X-Virus-Scanned: by AMaViS new-20020517 +Status: OR + + +On Fri, 20 Sep 2002, Mike Mascari wrote: + +> Bruce Momjian wrote: +> > Mike Mascari wrote: +> > +> >>Actually, looking at the pg_pwd code, you want to determine a +> >>way for: +> >> +> >>1. Process 1 opens "foo" +> >>2. Process 2 opens "foo" +> >>3. Process 1 creates "bar" +> >>4. Process 1 renames "bar" to "foo" +> >>5. Process 2 can continue to read data from the open file handle +> >>and get the original "foo" data. +> > +> > +> > Yep, that's it. +> > +> +> So far, MoveFileEx("foo", "bar", MOVEFILE_REPLACE_EXISTING) +> returns "Access Denied" when Process 1 attempts the rename. But +> I'm continuing to investigate the possibilities... + +Does a sequence like +Process 1 opens "foo" +Process 2 opens "foo" +Process 1 creates "bar" +Process 1 renames "foo" to + - where something is generated to not overlap an existing file +Process 1 renames "bar" to "foo" +Process 2 continues reading +let you do the replace and keep reading (at the penalty that +you've now got to have a way to know when to remove the +various s) + + + +---------------------------(end of broadcast)--------------------------- +TIP 2: you can get off all lists at once with the unregister command + (send "unregister YourEmailAddressHere" to majordomo@postgresql.org) + +From pgsql-hackers-owner+M29184@postgresql.org Fri Sep 20 02:06:47 2002 +Return-path: +Received: from postgresql.org (postgresql.org [64.49.215.8]) + by candle.pha.pa.us (8.11.6/8.10.1) with ESMTP id g8K66jE24908 + for ; Fri, 20 Sep 2002 02:06:45 -0400 (EDT) +Received: from localhost (postgresql.org [64.49.215.8]) + by postgresql.org (Postfix) with ESMTP + id E6AB6476994; Fri, 20 Sep 2002 02:06:43 -0400 (EDT) +Received: from postgresql.org (postgresql.org [64.49.215.8]) + by postgresql.org (Postfix) with SMTP + id 5626C4760AB; Fri, 20 Sep 2002 02:06:41 -0400 (EDT) +Received: from localhost (postgresql.org [64.49.215.8]) + by postgresql.org (Postfix) with ESMTP id 0BFDC475EEE + for ; Fri, 20 Sep 2002 02:05:04 -0400 (EDT) +Received: from corvette.mascari.com (dhcp065-024-158-068.columbus.rr.com [65.24.158.68]) + by postgresql.org (Postfix) with ESMTP id BFD01475E83 + for ; Fri, 20 Sep 2002 02:05:02 -0400 (EDT) +Received: from mascari.com (ferrari.mascari.com [192.168.2.1]) + by corvette.mascari.com (8.9.3/8.9.3) with ESMTP id CAA18737; + Fri, 20 Sep 2002 02:03:29 -0400 +Message-ID: <3D8ABA3F.6030002@mascari.com> +Date: Fri, 20 Sep 2002 02:03:43 -0400 +From: Mike Mascari +User-Agent: Mozilla/5.0 (Windows; U; WinNT4.0; en-US; rv:1.0.1) Gecko/20020823 Netscape/7.0 +X-Accept-Language: en-us, en +MIME-Version: 1.0 +To: Stephan Szabo +cc: Bruce Momjian , + PostgreSQL-development +Subject: Re: [HACKERS] Win32 rename()/unlink() questions +References: <20020919224718.H36366-100000@megazone23.bigpanda.com> +Content-Type: text/plain; charset=us-ascii; format=flowed +Content-Transfer-Encoding: 7bit +X-MailScanner: Found to be clean +X-Virus-Scanned: by AMaViS new-20020517 +Precedence: bulk +Sender: pgsql-hackers-owner@postgresql.org +X-Virus-Scanned: by AMaViS new-20020517 +Status: ORr + +Stephan Szabo wrote: +> On Fri, 20 Sep 2002, Mike Mascari wrote: +>>Bruce Momjian wrote: +>>>Mike Mascari wrote: +>>>>Actually, looking at the pg_pwd code, you want to determine a +>>>>way for: +>>>> +>>>>1. Process 1 opens "foo" +>>>>2. Process 2 opens "foo" +>>>>3. Process 1 creates "bar" +>>>>4. Process 1 renames "bar" to "foo" +>>>>5. Process 2 can continue to read data from the open file handle +>>>>and get the original "foo" data. +>>> +>>> +>>>Yep, that's it. +>>> +>> +>>So far, MoveFileEx("foo", "bar", MOVEFILE_REPLACE_EXISTING) +>>returns "Access Denied" when Process 1 attempts the rename. But +>>I'm continuing to investigate the possibilities... +> +> +> Does a sequence like +> Process 1 opens "foo" +> Process 2 opens "foo" +> Process 1 creates "bar" +> Process 1 renames "foo" to +> - where something is generated to not overlap an existing file +> Process 1 renames "bar" to "foo" +> Process 2 continues reading +> let you do the replace and keep reading (at the penalty that +> you've now got to have a way to know when to remove the +> various s) + +Yes! Indeed that does work. + +Mike Mascari +mascarm@mascari.com + + +---------------------------(end of broadcast)--------------------------- +TIP 1: subscribe and unsubscribe commands go to majordomo@postgresql.org + +From mascarm@mascari.com Fri Sep 20 02:04:41 2002 +Return-path: +Received: from corvette.mascari.com (dhcp065-024-158-068.columbus.rr.com [65.24.158.68]) + by candle.pha.pa.us (8.11.6/8.10.1) with ESMTP id g8K64WE24578 + for ; Fri, 20 Sep 2002 02:04:38 -0400 (EDT) +Received: from mascari.com (ferrari.mascari.com [192.168.2.1]) + by corvette.mascari.com (8.9.3/8.9.3) with ESMTP id CAA18737; + Fri, 20 Sep 2002 02:03:29 -0400 +Message-ID: <3D8ABA3F.6030002@mascari.com> +Date: Fri, 20 Sep 2002 02:03:43 -0400 +From: Mike Mascari +User-Agent: Mozilla/5.0 (Windows; U; WinNT4.0; en-US; rv:1.0.1) Gecko/20020823 Netscape/7.0 +X-Accept-Language: en-us, en +MIME-Version: 1.0 +To: Stephan Szabo +cc: Bruce Momjian , + PostgreSQL-development + +Subject: Re: [HACKERS] Win32 rename()/unlink() questions +References: <20020919224718.H36366-100000@megazone23.bigpanda.com> +Content-Type: text/plain; charset=us-ascii; format=flowed +Content-Transfer-Encoding: 7bit +X-MailScanner: Found to be clean +Status: OR + +Stephan Szabo wrote: +> On Fri, 20 Sep 2002, Mike Mascari wrote: +>>Bruce Momjian wrote: +>>>Mike Mascari wrote: +>>>>Actually, looking at the pg_pwd code, you want to determine a +>>>>way for: +>>>> +>>>>1. Process 1 opens "foo" +>>>>2. Process 2 opens "foo" +>>>>3. Process 1 creates "bar" +>>>>4. Process 1 renames "bar" to "foo" +>>>>5. Process 2 can continue to read data from the open file handle +>>>>and get the original "foo" data. +>>> +>>> +>>>Yep, that's it. +>>> +>> +>>So far, MoveFileEx("foo", "bar", MOVEFILE_REPLACE_EXISTING) +>>returns "Access Denied" when Process 1 attempts the rename. But +>>I'm continuing to investigate the possibilities... +> +> +> Does a sequence like +> Process 1 opens "foo" +> Process 2 opens "foo" +> Process 1 creates "bar" +> Process 1 renames "foo" to +> - where something is generated to not overlap an existing file +> Process 1 renames "bar" to "foo" +> Process 2 continues reading +> let you do the replace and keep reading (at the penalty that +> you've now got to have a way to know when to remove the +> various s) + +Yes! Indeed that does work. + +Mike Mascari +mascarm@mascari.com + + +From sszabo@megazone23.bigpanda.com Fri Sep 20 02:14:23 2002 +Return-path: +Received: from megazone.bigpanda.com (megazone.bigpanda.com [63.150.15.178]) + by candle.pha.pa.us (8.11.6/8.10.1) with ESMTP id g8K6EDE25582 + for ; Fri, 20 Sep 2002 02:14:21 -0400 (EDT) +Received: by megazone.bigpanda.com (Postfix, from userid 1001) + id B10E9D61E; Thu, 19 Sep 2002 23:14:14 -0700 (PDT) +Received: from localhost (localhost [127.0.0.1]) + by megazone.bigpanda.com (Postfix) with ESMTP + id A6B475C03; Thu, 19 Sep 2002 23:14:14 -0700 (PDT) +Date: Thu, 19 Sep 2002 23:14:14 -0700 (PDT) +From: Stephan Szabo +To: Mike Mascari +cc: Bruce Momjian , + PostgreSQL-development +Subject: Re: [HACKERS] Win32 rename()/unlink() questions +In-Reply-To: <3D8ABA3F.6030002@mascari.com> +Message-ID: <20020919230827.A36505-100000@megazone23.bigpanda.com> +MIME-Version: 1.0 +Content-Type: TEXT/PLAIN; charset=US-ASCII +Status: OR + +On Fri, 20 Sep 2002, Mike Mascari wrote: + +> Stephan Szabo wrote: +> > On Fri, 20 Sep 2002, Mike Mascari wrote: +> >>So far, MoveFileEx("foo", "bar", MOVEFILE_REPLACE_EXISTING) +> >>returns "Access Denied" when Process 1 attempts the rename. But +> >>I'm continuing to investigate the possibilities... +> > +> > +> > Does a sequence like +> > Process 1 opens "foo" +> > Process 2 opens "foo" +> > Process 1 creates "bar" +> > Process 1 renames "foo" to +> > - where something is generated to not overlap an existing file +> > Process 1 renames "bar" to "foo" +> > Process 2 continues reading +> > let you do the replace and keep reading (at the penalty that +> > you've now got to have a way to know when to remove the +> > various s) +> +> Yes! Indeed that does work. + +Thinking back, I think that may still fail on Win95 (using MoveFile). +Once in the past I had to work on (un)installers for Win* and I +vaguely remember Win95 being more strict than Win98 but that may just +have been with moving the executable you're currently running. + + +From pgsql-hackers-owner+M29185@postgresql.org Fri Sep 20 02:14:29 2002 +Return-path: +Received: from postgresql.org (postgresql.org [64.49.215.8]) + by candle.pha.pa.us (8.11.6/8.10.1) with ESMTP id g8K6ERE25614 + for ; Fri, 20 Sep 2002 02:14:27 -0400 (EDT) +Received: from localhost (postgresql.org [64.49.215.8]) + by postgresql.org (Postfix) with ESMTP + id B0200476D0C; Fri, 20 Sep 2002 02:14:26 -0400 (EDT) +Received: from postgresql.org (postgresql.org [64.49.215.8]) + by postgresql.org (Postfix) with SMTP + id D323F47655C; Fri, 20 Sep 2002 02:14:24 -0400 (EDT) +Received: from localhost (postgresql.org [64.49.215.8]) + by postgresql.org (Postfix) with ESMTP id 9EEBF476D02 + for ; Fri, 20 Sep 2002 02:14:20 -0400 (EDT) +Received: from megazone.bigpanda.com (megazone.bigpanda.com [63.150.15.178]) + by postgresql.org (Postfix) with ESMTP id 695B1475EAA + for ; Fri, 20 Sep 2002 02:14:16 -0400 (EDT) +Received: by megazone.bigpanda.com (Postfix, from userid 1001) + id B10E9D61E; Thu, 19 Sep 2002 23:14:14 -0700 (PDT) +Received: from localhost (localhost [127.0.0.1]) + by megazone.bigpanda.com (Postfix) with ESMTP + id A6B475C03; Thu, 19 Sep 2002 23:14:14 -0700 (PDT) +Date: Thu, 19 Sep 2002 23:14:14 -0700 (PDT) +From: Stephan Szabo +To: Mike Mascari +cc: Bruce Momjian , + PostgreSQL-development +Subject: Re: [HACKERS] Win32 rename()/unlink() questions +In-Reply-To: <3D8ABA3F.6030002@mascari.com> +Message-ID: <20020919230827.A36505-100000@megazone23.bigpanda.com> +MIME-Version: 1.0 +Content-Type: TEXT/PLAIN; charset=US-ASCII +X-Virus-Scanned: by AMaViS new-20020517 +Precedence: bulk +Sender: pgsql-hackers-owner@postgresql.org +X-Virus-Scanned: by AMaViS new-20020517 +Status: OR + +On Fri, 20 Sep 2002, Mike Mascari wrote: + +> Stephan Szabo wrote: +> > On Fri, 20 Sep 2002, Mike Mascari wrote: +> >>So far, MoveFileEx("foo", "bar", MOVEFILE_REPLACE_EXISTING) +> >>returns "Access Denied" when Process 1 attempts the rename. But +> >>I'm continuing to investigate the possibilities... +> > +> > +> > Does a sequence like +> > Process 1 opens "foo" +> > Process 2 opens "foo" +> > Process 1 creates "bar" +> > Process 1 renames "foo" to +> > - where something is generated to not overlap an existing file +> > Process 1 renames "bar" to "foo" +> > Process 2 continues reading +> > let you do the replace and keep reading (at the penalty that +> > you've now got to have a way to know when to remove the +> > various s) +> +> Yes! Indeed that does work. + +Thinking back, I think that may still fail on Win95 (using MoveFile). +Once in the past I had to work on (un)installers for Win* and I +vaguely remember Win95 being more strict than Win98 but that may just +have been with moving the executable you're currently running. + + +---------------------------(end of broadcast)--------------------------- +TIP 1: subscribe and unsubscribe commands go to majordomo@postgresql.org + +From pgsql-hackers-owner+M29189@postgresql.org Fri Sep 20 03:22:41 2002 +Return-path: +Received: from postgresql.org (postgresql.org [64.49.215.8]) + by candle.pha.pa.us (8.11.6/8.10.1) with ESMTP id g8K7MdE01450 + for ; Fri, 20 Sep 2002 03:22:39 -0400 (EDT) +Received: from localhost (postgresql.org [64.49.215.8]) + by postgresql.org (Postfix) with ESMTP + id 211C1476DAC; Fri, 20 Sep 2002 03:20:05 -0400 (EDT) +Received: from postgresql.org (postgresql.org [64.49.215.8]) + by postgresql.org (Postfix) with SMTP + id D76C4475F73; Fri, 20 Sep 2002 03:18:20 -0400 (EDT) +Received: from localhost (postgresql.org [64.49.215.8]) + by postgresql.org (Postfix) with ESMTP id 8C2E0476D57 + for ; Fri, 20 Sep 2002 03:15:32 -0400 (EDT) +Received: from corvette.mascari.com (dhcp065-024-158-068.columbus.rr.com [65.24.158.68]) + by postgresql.org (Postfix) with ESMTP id 5098F476839 + for ; Fri, 20 Sep 2002 03:15:26 -0400 (EDT) +Received: from mascari.com (ferrari.mascari.com [192.168.2.1]) + by corvette.mascari.com (8.9.3/8.9.3) with ESMTP id DAA18894; + Fri, 20 Sep 2002 03:13:06 -0400 +Message-ID: <3D8ACA96.80504@mascari.com> +Date: Fri, 20 Sep 2002 03:13:26 -0400 +From: Mike Mascari +User-Agent: Mozilla/5.0 (Windows; U; WinNT4.0; en-US; rv:1.0.1) Gecko/20020823 Netscape/7.0 +X-Accept-Language: en-us, en +MIME-Version: 1.0 +To: Stephan Szabo +cc: Bruce Momjian , + PostgreSQL-development +Subject: Re: [HACKERS] Win32 rename()/unlink() questions +References: <20020919230827.A36505-100000@megazone23.bigpanda.com> +Content-Type: text/plain; charset=us-ascii; format=flowed +Content-Transfer-Encoding: 7bit +X-MailScanner: Found to be clean +X-Virus-Scanned: by AMaViS new-20020517 +Precedence: bulk +Sender: pgsql-hackers-owner@postgresql.org +X-Virus-Scanned: by AMaViS new-20020517 +Status: ORr + +Stephan Szabo wrote: +> On Fri, 20 Sep 2002, Mike Mascari wrote: +>> +>>Yes! Indeed that does work. +> +> +> Thinking back, I think that may still fail on Win95 (using MoveFile). +> Once in the past I had to work on (un)installers for Win* and I +> vaguely remember Win95 being more strict than Win98 but that may just +> have been with moving the executable you're currently running. + +Well, here's the test: + +foo.txt contains "This is FOO!" +bar.txt contains "This is BAR!" + +Process 1 opens foo.txt +Process 2 opens foo.txt +Process 1 sleeps 7.5 seconds +Process 2 sleeps 15 seconds +Process 1 uses MoveFile() to rename "foo.txt" to "foo2.txt" +Process 1 uses MoveFile() to rename "bar.txt" to "foo.txt" +Process 1 uses DeleteFile() to remove "foo2.txt" +Process 2 awakens and displays "This is FOO!" + +On the filesystem, we then have: + +foo.txt containing "This is BAR!" + +The good news is that this works fine under NT 4 using just +MoveFile(). The bad news is that it requires the files be opened +using CreateFile() with the FILE_SHARE_DELETE flag set. The C +library which ships with Visual C++ 6 ultimately calls +CreateFile() via fopen() but with no opportunity through the +standard C library routines to use the FILE_SHARE_DELETE flag. +And the FILE_SHARE_DELETE flag cannot be used under Windows +95/98 (Bad Parameter). Which means, on those platforms, there +still doesn't appear to be a solution. Under NT/XP/2K, +AllocateFile() will have to modified to call CreateFile() +instead of fopen(). I'm not sure about ME, but I suspect it +behaves similarly to 95/98. + +Mike Mascari +mascarm@mascari.com + + + + + +---------------------------(end of broadcast)--------------------------- +TIP 1: subscribe and unsubscribe commands go to majordomo@postgresql.org + +From mascarm@mascari.com Fri Sep 20 03:14:03 2002 +Return-path: +Received: from corvette.mascari.com (dhcp065-024-158-068.columbus.rr.com [65.24.158.68]) + by candle.pha.pa.us (8.11.6/8.10.1) with ESMTP id g8K7DwE00605 + for ; Fri, 20 Sep 2002 03:14:01 -0400 (EDT) +Received: from mascari.com (ferrari.mascari.com [192.168.2.1]) + by corvette.mascari.com (8.9.3/8.9.3) with ESMTP id DAA18894; + Fri, 20 Sep 2002 03:13:06 -0400 +Message-ID: <3D8ACA96.80504@mascari.com> +Date: Fri, 20 Sep 2002 03:13:26 -0400 +From: Mike Mascari +User-Agent: Mozilla/5.0 (Windows; U; WinNT4.0; en-US; rv:1.0.1) Gecko/20020823 Netscape/7.0 +X-Accept-Language: en-us, en +MIME-Version: 1.0 +To: Stephan Szabo +cc: Bruce Momjian , + PostgreSQL-development + +Subject: Re: [HACKERS] Win32 rename()/unlink() questions +References: <20020919230827.A36505-100000@megazone23.bigpanda.com> +Content-Type: text/plain; charset=us-ascii; format=flowed +Content-Transfer-Encoding: 7bit +X-MailScanner: Found to be clean +Status: OR + +Stephan Szabo wrote: +> On Fri, 20 Sep 2002, Mike Mascari wrote: +>> +>>Yes! Indeed that does work. +> +> +> Thinking back, I think that may still fail on Win95 (using MoveFile). +> Once in the past I had to work on (un)installers for Win* and I +> vaguely remember Win95 being more strict than Win98 but that may just +> have been with moving the executable you're currently running. + +Well, here's the test: + +foo.txt contains "This is FOO!" +bar.txt contains "This is BAR!" + +Process 1 opens foo.txt +Process 2 opens foo.txt +Process 1 sleeps 7.5 seconds +Process 2 sleeps 15 seconds +Process 1 uses MoveFile() to rename "foo.txt" to "foo2.txt" +Process 1 uses MoveFile() to rename "bar.txt" to "foo.txt" +Process 1 uses DeleteFile() to remove "foo2.txt" +Process 2 awakens and displays "This is FOO!" + +On the filesystem, we then have: + +foo.txt containing "This is BAR!" + +The good news is that this works fine under NT 4 using just +MoveFile(). The bad news is that it requires the files be opened +using CreateFile() with the FILE_SHARE_DELETE flag set. The C +library which ships with Visual C++ 6 ultimately calls +CreateFile() via fopen() but with no opportunity through the +standard C library routines to use the FILE_SHARE_DELETE flag. +And the FILE_SHARE_DELETE flag cannot be used under Windows +95/98 (Bad Parameter). Which means, on those platforms, there +still doesn't appear to be a solution. Under NT/XP/2K, +AllocateFile() will have to modified to call CreateFile() +instead of fopen(). I'm not sure about ME, but I suspect it +behaves similarly to 95/98. + +Mike Mascari +mascarm@mascari.com + + + + + +From tgl@sss.pgh.pa.us Fri Sep 20 10:28:40 2002 +Return-path: +Received: from sss.pgh.pa.us (root@[192.204.191.242]) + by candle.pha.pa.us (8.11.6/8.10.1) with ESMTP id g8KESbE13042 + for ; Fri, 20 Sep 2002 10:28:39 -0400 (EDT) +Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) + by sss.pgh.pa.us (8.12.5/8.12.5) with ESMTP id g8KERq5D016068; + Fri, 20 Sep 2002 10:27:52 -0400 (EDT) +To: Stephan Szabo +cc: Mike Mascari , Bruce Momjian , + PostgreSQL-development +Subject: Re: [HACKERS] Win32 rename()/unlink() questions +In-Reply-To: <20020919224718.H36366-100000@megazone23.bigpanda.com> +References: <20020919224718.H36366-100000@megazone23.bigpanda.com> +Comments: In-reply-to Stephan Szabo + message dated "Thu, 19 Sep 2002 22:50:36 -0700" +Date: Fri, 20 Sep 2002 10:27:52 -0400 +Message-ID: <16067.1032532072@sss.pgh.pa.us> +From: Tom Lane +Status: OR + +Stephan Szabo writes: +> ... let you do the replace and keep reading (at the penalty that +> you've now got to have a way to know when to remove the +> various s) + +That is the hard part. Mike's description omitted one crucial step: + +6. The old "foo" goes away when the last open file handle for it is +closed. + +I doubt there is any practical way for Postgres to cause that to happen +if the OS itself does not have any support for it. + + regards, tom lane + +From pgsql-hackers-owner+M29205@postgresql.org Fri Sep 20 10:36:48 2002 +Return-path: +Received: from postgresql.org (postgresql.org [64.49.215.8]) + by candle.pha.pa.us (8.11.6/8.10.1) with ESMTP id g8KEalE13770 + for ; Fri, 20 Sep 2002 10:36:47 -0400 (EDT) +Received: from localhost (postgresql.org [64.49.215.8]) + by postgresql.org (Postfix) with ESMTP + id BBC23476E72; Fri, 20 Sep 2002 10:35:40 -0400 (EDT) +Received: from postgresql.org (postgresql.org [64.49.215.8]) + by postgresql.org (Postfix) with SMTP + id 00890476D13; Fri, 20 Sep 2002 10:35:31 -0400 (EDT) +Received: from localhost (postgresql.org [64.49.215.8]) + by postgresql.org (Postfix) with ESMTP id 5D2BC476D6D + for ; Fri, 20 Sep 2002 10:30:17 -0400 (EDT) +Received: from sss.pgh.pa.us (unknown [192.204.191.242]) + by postgresql.org (Postfix) with ESMTP id B17FE476CD8 + for ; Fri, 20 Sep 2002 10:30:15 -0400 (EDT) +Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) + by sss.pgh.pa.us (8.12.5/8.12.5) with ESMTP id g8KERq5D016068; + Fri, 20 Sep 2002 10:27:52 -0400 (EDT) +To: Stephan Szabo +cc: Mike Mascari , Bruce Momjian , + PostgreSQL-development +Subject: Re: [HACKERS] Win32 rename()/unlink() questions +In-Reply-To: <20020919224718.H36366-100000@megazone23.bigpanda.com> +References: <20020919224718.H36366-100000@megazone23.bigpanda.com> +Comments: In-reply-to Stephan Szabo + message dated "Thu, 19 Sep 2002 22:50:36 -0700" +Date: Fri, 20 Sep 2002 10:27:52 -0400 +Message-ID: <16067.1032532072@sss.pgh.pa.us> +From: Tom Lane +X-Virus-Scanned: by AMaViS new-20020517 +Precedence: bulk +Sender: pgsql-hackers-owner@postgresql.org +X-Virus-Scanned: by AMaViS new-20020517 +Status: OR + +Stephan Szabo writes: +> ... let you do the replace and keep reading (at the penalty that +> you've now got to have a way to know when to remove the +> various s) + +That is the hard part. Mike's description omitted one crucial step: + +6. The old "foo" goes away when the last open file handle for it is +closed. + +I doubt there is any practical way for Postgres to cause that to happen +if the OS itself does not have any support for it. + + regards, tom lane + +---------------------------(end of broadcast)--------------------------- +TIP 1: subscribe and unsubscribe commands go to majordomo@postgresql.org + +From pgsql-hackers-owner+M29206@postgresql.org Fri Sep 20 10:37:53 2002 +Return-path: +Received: from postgresql.org (postgresql.org [64.49.215.8]) + by candle.pha.pa.us (8.11.6/8.10.1) with ESMTP id g8KEbpE13898 + for ; Fri, 20 Sep 2002 10:37:51 -0400 (EDT) +Received: from localhost (postgresql.org [64.49.215.8]) + by postgresql.org (Postfix) with ESMTP + id 891F9476DC6; Fri, 20 Sep 2002 10:36:31 -0400 (EDT) +Received: from postgresql.org (postgresql.org [64.49.215.8]) + by postgresql.org (Postfix) with SMTP + id 2207D476F07; Fri, 20 Sep 2002 10:36:22 -0400 (EDT) +Received: from localhost (postgresql.org [64.49.215.8]) + by postgresql.org (Postfix) with ESMTP id 90195476DD2 + for ; Fri, 20 Sep 2002 10:33:48 -0400 (EDT) +Received: from candle.pha.pa.us (momjian.navpoint.com [207.106.42.251]) + by postgresql.org (Postfix) with ESMTP id 5ECE6476DB5 + for ; Fri, 20 Sep 2002 10:33:46 -0400 (EDT) +Received: (from pgman@localhost) + by candle.pha.pa.us (8.11.6/8.10.1) id g8KEVMg13344; + Fri, 20 Sep 2002 10:31:22 -0400 (EDT) +From: Bruce Momjian +Message-ID: <200209201431.g8KEVMg13344@candle.pha.pa.us> +Subject: Re: [HACKERS] Win32 rename()/unlink() questions +In-Reply-To: <3D8ACA96.80504@mascari.com> +To: Mike Mascari +Date: Fri, 20 Sep 2002 10:31:22 -0400 (EDT) +cc: Stephan Szabo , + PostgreSQL-development +X-Mailer: ELM [version 2.4ME+ PL99 (25)] +MIME-Version: 1.0 +Content-Transfer-Encoding: 7bit +Content-Type: text/plain; charset=US-ASCII +X-Virus-Scanned: by AMaViS new-20020517 +Precedence: bulk +Sender: pgsql-hackers-owner@postgresql.org +X-Virus-Scanned: by AMaViS new-20020517 +Status: OR + + +I don't think we are not going to be supporting Win9X so there isn't an +issue there. We will be supporting Win2000/NT/XP. + +I don't understand FILE_SHARE_DELETE. I read the description at: + + http://msdn.microsoft.com/library/default.asp?url=/library/en-us/fileio/base/createfile.asp + +but I don't understand it: + + FILE_SHARE_DELETE - Windows NT/2000/XP: Subsequent open operations on + the object will succeed only if delete access is requested. + +--------------------------------------------------------------------------- + +Mike Mascari wrote: +> Stephan Szabo wrote: +> > On Fri, 20 Sep 2002, Mike Mascari wrote: +> >> +> >>Yes! Indeed that does work. +> > +> > +> > Thinking back, I think that may still fail on Win95 (using MoveFile). +> > Once in the past I had to work on (un)installers for Win* and I +> > vaguely remember Win95 being more strict than Win98 but that may just +> > have been with moving the executable you're currently running. +> +> Well, here's the test: +> +> foo.txt contains "This is FOO!" +> bar.txt contains "This is BAR!" +> +> Process 1 opens foo.txt +> Process 2 opens foo.txt +> Process 1 sleeps 7.5 seconds +> Process 2 sleeps 15 seconds +> Process 1 uses MoveFile() to rename "foo.txt" to "foo2.txt" +> Process 1 uses MoveFile() to rename "bar.txt" to "foo.txt" +> Process 1 uses DeleteFile() to remove "foo2.txt" +> Process 2 awakens and displays "This is FOO!" +> +> On the filesystem, we then have: +> +> foo.txt containing "This is BAR!" +> +> The good news is that this works fine under NT 4 using just +> MoveFile(). The bad news is that it requires the files be opened +> using CreateFile() with the FILE_SHARE_DELETE flag set. The C +> library which ships with Visual C++ 6 ultimately calls +> CreateFile() via fopen() but with no opportunity through the +> standard C library routines to use the FILE_SHARE_DELETE flag. +> And the FILE_SHARE_DELETE flag cannot be used under Windows +> 95/98 (Bad Parameter). Which means, on those platforms, there +> still doesn't appear to be a solution. Under NT/XP/2K, +> AllocateFile() will have to modified to call CreateFile() +> instead of fopen(). I'm not sure about ME, but I suspect it +> behaves similarly to 95/98. +> +> Mike Mascari +> mascarm@mascari.com +> +> +> +> +> +> ---------------------------(end of broadcast)--------------------------- +> TIP 1: subscribe and unsubscribe commands go to majordomo@postgresql.org +> + +-- + Bruce Momjian | http://candle.pha.pa.us + pgman@candle.pha.pa.us | (610) 359-1001 + + If your life is a hard drive, | 13 Roberts Road + + Christ can be your backup. | Newtown Square, Pennsylvania 19073 + +---------------------------(end of broadcast)--------------------------- +TIP 6: Have you searched our list archives? + +http://archives.postgresql.org + +From mascarm@mascari.com Fri Sep 20 10:57:31 2002 +Return-path: +Received: from corvette.mascari.com (dhcp065-024-158-068.columbus.rr.com [65.24.158.68]) + by candle.pha.pa.us (8.11.6/8.10.1) with ESMTP id g8KEvRE16100 + for ; Fri, 20 Sep 2002 10:57:29 -0400 (EDT) +Received: from mascari.com (ferrari.mascari.com [192.168.2.1]) + by corvette.mascari.com (8.9.3/8.9.3) with ESMTP id KAA20019; + Fri, 20 Sep 2002 10:56:39 -0400 +Message-ID: <3D8B373C.7060102@mascari.com> +Date: Fri, 20 Sep 2002 10:57:00 -0400 +From: Mike Mascari +User-Agent: Mozilla/5.0 (Windows; U; WinNT4.0; en-US; rv:1.0.1) Gecko/20020823 Netscape/7.0 +X-Accept-Language: en-us, en +MIME-Version: 1.0 +To: Bruce Momjian +cc: Stephan Szabo , + PostgreSQL-development + +Subject: Re: [HACKERS] Win32 rename()/unlink() questions +References: <200209201431.g8KEVMg13344@candle.pha.pa.us> +Content-Type: text/plain; charset=us-ascii; format=flowed +Content-Transfer-Encoding: 7bit +X-MailScanner: Found to be clean +Status: ORr + +Bruce Momjian wrote: +> I don't think we are not going to be supporting Win9X so there isn't an +> issue there. We will be supporting Win2000/NT/XP. +> +> I don't understand FILE_SHARE_DELETE. I read the description at: +> +> http://msdn.microsoft.com/library/default.asp?url=/library/en-us/fileio/base/createfile.asp +> +> but I don't understand it: +> +> FILE_SHARE_DELETE - Windows NT/2000/XP: Subsequent open operations on +> the object will succeed only if delete access is requested. + +I think that's a rather poor description. I think it just means +that if the file is opened once via CreateFile() with +FILE_SHARE_DELETE, then any subsequent CreateFile() calls will +fail unless they too have FILE_SHARE_DELETE. In other words, if +one of us can delete this file while its open, any of us can. + +Mike Mascari +mascarm@mascari.com + + + + + +From pgsql-hackers-owner+M29208@postgresql.org Fri Sep 20 11:30:26 2002 +Return-path: +Received: from west.navpoint.com (west.navpoint.com [207.106.42.13]) + by candle.pha.pa.us (8.11.6/8.10.1) with ESMTP id g8KFUOE24840 + for ; Fri, 20 Sep 2002 11:30:25 -0400 (EDT) +Received: from postgresql.org (postgresql.org [64.49.215.8]) + by west.navpoint.com (8.11.6/8.10.1) with ESMTP id g8KFBP217840 + for ; Fri, 20 Sep 2002 11:11:25 -0400 (EDT) +Received: from localhost (postgresql.org [64.49.215.8]) + by postgresql.org (Postfix) with ESMTP + id BD0D2476E5B; Fri, 20 Sep 2002 11:09:49 -0400 (EDT) +Received: from postgresql.org (postgresql.org [64.49.215.8]) + by postgresql.org (Postfix) with SMTP + id 4691C476D5D; Fri, 20 Sep 2002 11:09:47 -0400 (EDT) +Received: from localhost (postgresql.org [64.49.215.8]) + by postgresql.org (Postfix) with ESMTP id 8341F475CB4 + for ; Fri, 20 Sep 2002 10:58:12 -0400 (EDT) +Received: from corvette.mascari.com (dhcp065-024-158-068.columbus.rr.com [65.24.158.68]) + by postgresql.org (Postfix) with ESMTP id B1E1A474E5C + for ; Fri, 20 Sep 2002 10:58:10 -0400 (EDT) +Received: from mascari.com (ferrari.mascari.com [192.168.2.1]) + by corvette.mascari.com (8.9.3/8.9.3) with ESMTP id KAA20019; + Fri, 20 Sep 2002 10:56:39 -0400 +Message-ID: <3D8B373C.7060102@mascari.com> +Date: Fri, 20 Sep 2002 10:57:00 -0400 +From: Mike Mascari +User-Agent: Mozilla/5.0 (Windows; U; WinNT4.0; en-US; rv:1.0.1) Gecko/20020823 Netscape/7.0 +X-Accept-Language: en-us, en +MIME-Version: 1.0 +To: Bruce Momjian +cc: Stephan Szabo , + PostgreSQL-development +Subject: Re: [HACKERS] Win32 rename()/unlink() questions +References: <200209201431.g8KEVMg13344@candle.pha.pa.us> +Content-Type: text/plain; charset=us-ascii; format=flowed +Content-Transfer-Encoding: 7bit +X-MailScanner: Found to be clean +X-Virus-Scanned: by AMaViS new-20020517 +Precedence: bulk +Sender: pgsql-hackers-owner@postgresql.org +X-Virus-Scanned: by AMaViS new-20020517 +Status: OR + +Bruce Momjian wrote: +> I don't think we are not going to be supporting Win9X so there isn't an +> issue there. We will be supporting Win2000/NT/XP. +> +> I don't understand FILE_SHARE_DELETE. I read the description at: +> +> http://msdn.microsoft.com/library/default.asp?url=/library/en-us/fileio/base/createfile.asp +> +> but I don't understand it: +> +> FILE_SHARE_DELETE - Windows NT/2000/XP: Subsequent open operations on +> the object will succeed only if delete access is requested. + +I think that's a rather poor description. I think it just means +that if the file is opened once via CreateFile() with +FILE_SHARE_DELETE, then any subsequent CreateFile() calls will +fail unless they too have FILE_SHARE_DELETE. In other words, if +one of us can delete this file while its open, any of us can. + +Mike Mascari +mascarm@mascari.com + + + + + +---------------------------(end of broadcast)--------------------------- +TIP 4: Don't 'kill -9' the postmaster + +From pgsql-hackers-owner+M29213@postgresql.org Fri Sep 20 11:30:47 2002 +Return-path: +Received: from postgresql.org (postgresql.org [64.49.215.8]) + by candle.pha.pa.us (8.11.6/8.10.1) with ESMTP id g8KFUkE24923 + for ; Fri, 20 Sep 2002 11:30:46 -0400 (EDT) +Received: from localhost (postgresql.org [64.49.215.8]) + by postgresql.org (Postfix) with ESMTP + id DFE91476EA6; Fri, 20 Sep 2002 11:28:47 -0400 (EDT) +Received: from postgresql.org (postgresql.org [64.49.215.8]) + by postgresql.org (Postfix) with SMTP + id 124F8476E95; Fri, 20 Sep 2002 11:28:46 -0400 (EDT) +Received: from localhost (postgresql.org [64.49.215.8]) + by postgresql.org (Postfix) with ESMTP id C8ADF476F70 + for ; Fri, 20 Sep 2002 11:26:25 -0400 (EDT) +Received: from candle.pha.pa.us (momjian.navpoint.com [207.106.42.251]) + by postgresql.org (Postfix) with ESMTP id DC5BD476F53 + for ; Fri, 20 Sep 2002 11:26:19 -0400 (EDT) +Received: (from pgman@localhost) + by candle.pha.pa.us (8.11.6/8.10.1) id g8KF5ch17250; + Fri, 20 Sep 2002 11:05:38 -0400 (EDT) +From: Bruce Momjian +Message-ID: <200209201505.g8KF5ch17250@candle.pha.pa.us> +Subject: Re: [HACKERS] Win32 rename()/unlink() questions +In-Reply-To: <3D8B373C.7060102@mascari.com> +To: Mike Mascari +Date: Fri, 20 Sep 2002 11:05:38 -0400 (EDT) +cc: Stephan Szabo , + PostgreSQL-development +X-Mailer: ELM [version 2.4ME+ PL99 (25)] +MIME-Version: 1.0 +Content-Transfer-Encoding: 7bit +Content-Type: text/plain; charset=US-ASCII +X-Virus-Scanned: by AMaViS new-20020517 +Precedence: bulk +Sender: pgsql-hackers-owner@postgresql.org +X-Virus-Scanned: by AMaViS new-20020517 +Status: OR + +Mike Mascari wrote: +> Bruce Momjian wrote: +> > I don't think we are not going to be supporting Win9X so there isn't an +> > issue there. We will be supporting Win2000/NT/XP. +> > +> > I don't understand FILE_SHARE_DELETE. I read the description at: +> > +> > http://msdn.microsoft.com/library/default.asp?url=/library/en-us/fileio/base/createfile.asp +> > +> > but I don't understand it: +> > +> > FILE_SHARE_DELETE - Windows NT/2000/XP: Subsequent open operations on +> > the object will succeed only if delete access is requested. +> +> I think that's a rather poor description. I think it just means +> that if the file is opened once via CreateFile() with +> FILE_SHARE_DELETE, then any subsequent CreateFile() calls will +> fail unless they too have FILE_SHARE_DELETE. In other words, if +> one of us can delete this file while its open, any of us can. + +I don't understand what that gets us. + +-- + Bruce Momjian | http://candle.pha.pa.us + pgman@candle.pha.pa.us | (610) 359-1001 + + If your life is a hard drive, | 13 Roberts Road + + Christ can be your backup. | Newtown Square, Pennsylvania 19073 + +---------------------------(end of broadcast)--------------------------- +TIP 4: Don't 'kill -9' the postmaster + +From pgsql-hackers-owner+M29210@postgresql.org Fri Sep 20 11:26:52 2002 +Return-path: +Received: from postgresql.org (postgresql.org [64.49.215.8]) + by candle.pha.pa.us (8.11.6/8.10.1) with ESMTP id g8KFQoE24268 + for ; Fri, 20 Sep 2002 11:26:51 -0400 (EDT) +Received: from localhost (postgresql.org [64.49.215.8]) + by postgresql.org (Postfix) with ESMTP + id 7ED2C476E31; Fri, 20 Sep 2002 11:25:32 -0400 (EDT) +Received: from postgresql.org (postgresql.org [64.49.215.8]) + by postgresql.org (Postfix) with SMTP + id 89A6C476E66; Fri, 20 Sep 2002 11:25:18 -0400 (EDT) +Received: from localhost (postgresql.org [64.49.215.8]) + by postgresql.org (Postfix) with ESMTP id 4033C476DD3 + for ; Fri, 20 Sep 2002 11:11:44 -0400 (EDT) +Received: from megazone.bigpanda.com (megazone.bigpanda.com [63.150.15.178]) + by postgresql.org (Postfix) with ESMTP id A46C9476D7C + for ; Fri, 20 Sep 2002 11:11:43 -0400 (EDT) +Received: by megazone.bigpanda.com (Postfix, from userid 1001) + id 5F343D61C; Fri, 20 Sep 2002 08:10:19 -0700 (PDT) +Received: from localhost (localhost [127.0.0.1]) + by megazone.bigpanda.com (Postfix) with ESMTP + id 54E705C02; Fri, 20 Sep 2002 08:10:19 -0700 (PDT) +Date: Fri, 20 Sep 2002 08:10:19 -0700 (PDT) +From: Stephan Szabo +To: Mike Mascari +cc: Bruce Momjian , + PostgreSQL-development +Subject: Re: [HACKERS] Win32 rename()/unlink() questions +In-Reply-To: <3D8B373C.7060102@mascari.com> +Message-ID: <20020920080949.H40440-100000@megazone23.bigpanda.com> +MIME-Version: 1.0 +Content-Type: TEXT/PLAIN; charset=US-ASCII +X-Virus-Scanned: by AMaViS new-20020517 +Precedence: bulk +Sender: pgsql-hackers-owner@postgresql.org +X-Virus-Scanned: by AMaViS new-20020517 +Status: OR + +On Fri, 20 Sep 2002, Mike Mascari wrote: + +> Bruce Momjian wrote: +> > I don't think we are not going to be supporting Win9X so there isn't an +> > issue there. We will be supporting Win2000/NT/XP. +> > +> > I don't understand FILE_SHARE_DELETE. I read the description at: +> > +> > http://msdn.microsoft.com/library/default.asp?url=/library/en-us/fileio/base/createfile.asp +> > +> > but I don't understand it: +> > +> > FILE_SHARE_DELETE - Windows NT/2000/XP: Subsequent open operations on +> > the object will succeed only if delete access is requested. +> +> I think that's a rather poor description. I think it just means +> that if the file is opened once via CreateFile() with +> FILE_SHARE_DELETE, then any subsequent CreateFile() calls will +> fail unless they too have FILE_SHARE_DELETE. In other words, if +> one of us can delete this file while its open, any of us can. + +The question is, what happens if two people have the file open +and one goes and tries to delete it? Can the other still read +from it? + + +---------------------------(end of broadcast)--------------------------- +TIP 4: Don't 'kill -9' the postmaster + +From sszabo@megazone23.bigpanda.com Fri Sep 20 11:29:09 2002 +Return-path: +Received: from west.navpoint.com (west.navpoint.com [207.106.42.13]) + by candle.pha.pa.us (8.11.6/8.10.1) with ESMTP id g8KFT6E24617 + for ; Fri, 20 Sep 2002 11:29:08 -0400 (EDT) +Received: from megazone.bigpanda.com (megazone.bigpanda.com [63.150.15.178]) + by west.navpoint.com (8.11.6/8.10.1) with ESMTP id g8KFBZ217956 + for ; Fri, 20 Sep 2002 11:11:35 -0400 (EDT) +Received: by megazone.bigpanda.com (Postfix, from userid 1001) + id 5F343D61C; Fri, 20 Sep 2002 08:10:19 -0700 (PDT) +Received: from localhost (localhost [127.0.0.1]) + by megazone.bigpanda.com (Postfix) with ESMTP + id 54E705C02; Fri, 20 Sep 2002 08:10:19 -0700 (PDT) +Date: Fri, 20 Sep 2002 08:10:19 -0700 (PDT) +From: Stephan Szabo +To: Mike Mascari +cc: Bruce Momjian , + PostgreSQL-development +Subject: Re: [HACKERS] Win32 rename()/unlink() questions +In-Reply-To: <3D8B373C.7060102@mascari.com> +Message-ID: <20020920080949.H40440-100000@megazone23.bigpanda.com> +MIME-Version: 1.0 +Content-Type: TEXT/PLAIN; charset=US-ASCII +Status: OR + +On Fri, 20 Sep 2002, Mike Mascari wrote: + +> Bruce Momjian wrote: +> > I don't think we are not going to be supporting Win9X so there isn't an +> > issue there. We will be supporting Win2000/NT/XP. +> > +> > I don't understand FILE_SHARE_DELETE. I read the description at: +> > +> > http://msdn.microsoft.com/library/default.asp?url=/library/en-us/fileio/base/createfile.asp +> > +> > but I don't understand it: +> > +> > FILE_SHARE_DELETE - Windows NT/2000/XP: Subsequent open operations on +> > the object will succeed only if delete access is requested. +> +> I think that's a rather poor description. I think it just means +> that if the file is opened once via CreateFile() with +> FILE_SHARE_DELETE, then any subsequent CreateFile() calls will +> fail unless they too have FILE_SHARE_DELETE. In other words, if +> one of us can delete this file while its open, any of us can. + +The question is, what happens if two people have the file open +and one goes and tries to delete it? Can the other still read +from it? + + +From JanWieck@Yahoo.com Fri Sep 20 11:36:53 2002 +Return-path: +Received: from smtp017.mail.yahoo.com (smtp017.mail.yahoo.com [216.136.174.114]) + by candle.pha.pa.us (8.11.6/8.10.1) with SMTP id g8KFalE25760 + for ; Fri, 20 Sep 2002 11:36:52 -0400 (EDT) +Received: from psc.progress.com (HELO Yahoo.com) (janwieck@192.233.92.200 with plain) + by smtp.mail.vip.sc5.yahoo.com with SMTP; 20 Sep 2002 15:36:41 -0000 +Message-ID: <3D8B4087.AF0CD803@Yahoo.com> +Date: Fri, 20 Sep 2002 11:36:39 -0400 +From: Jan Wieck +Organization: Home +X-Mailer: Mozilla 4.79 [en] (Windows NT 5.0; U) +X-Accept-Language: en,ru +MIME-Version: 1.0 +To: Mike Mascari +cc: Stephan Szabo , + Bruce Momjian , + PostgreSQL-development +Subject: Re: [HACKERS] Win32 rename()/unlink() questions +References: <20020919230827.A36505-100000@megazone23.bigpanda.com> <3D8ACA96.80504@mascari.com> +Content-Type: text/plain; charset=us-ascii +Content-Transfer-Encoding: 7bit +Status: OR + +Mike Mascari wrote: + +> instead of fopen(). I'm not sure about ME, but I suspect it +> behaves similarly to 95/98. + +I just checked with Katie and the good news (tm) is that the Win32 port +we did here at PeerDirect doesn't support 95/98 and ME anyway. It does +support NT4, 2000 and XP. So don't bother. + + +Jan + +-- + +#======================================================================# +# It's easier to get forgiveness for being wrong than for being right. # +# Let's break this rule - forgive me. # +#================================================== JanWieck@Yahoo.com # + +From pgsql-hackers-owner+M29216@postgresql.org Fri Sep 20 11:45:47 2002 +Return-path: +Received: from postgresql.org (postgresql.org [64.49.215.8]) + by candle.pha.pa.us (8.11.6/8.10.1) with ESMTP id g8KFjkE26656 + for ; Fri, 20 Sep 2002 11:45:46 -0400 (EDT) +Received: from localhost (postgresql.org [64.49.215.8]) + by postgresql.org (Postfix) with ESMTP + id 75E01476DE2; Fri, 20 Sep 2002 11:44:30 -0400 (EDT) +Received: from postgresql.org (postgresql.org [64.49.215.8]) + by postgresql.org (Postfix) with SMTP + id E1897476E29; Fri, 20 Sep 2002 11:44:16 -0400 (EDT) +Received: from localhost (postgresql.org [64.49.215.8]) + by postgresql.org (Postfix) with ESMTP id 96D5C47625F + for ; Fri, 20 Sep 2002 11:38:15 -0400 (EDT) +Received: from smtp017.mail.yahoo.com (smtp017.mail.yahoo.com [216.136.174.114]) + by postgresql.org (Postfix) with SMTP id B00BA476225 + for ; Fri, 20 Sep 2002 11:38:14 -0400 (EDT) +Received: from psc.progress.com (HELO Yahoo.com) (janwieck@192.233.92.200 with plain) + by smtp.mail.vip.sc5.yahoo.com with SMTP; 20 Sep 2002 15:36:41 -0000 +Message-ID: <3D8B4087.AF0CD803@Yahoo.com> +Date: Fri, 20 Sep 2002 11:36:39 -0400 +From: Jan Wieck +Organization: Home +X-Mailer: Mozilla 4.79 [en] (Windows NT 5.0; U) +X-Accept-Language: en,ru +MIME-Version: 1.0 +To: Mike Mascari +cc: Stephan Szabo , + Bruce Momjian , + PostgreSQL-development +Subject: Re: [HACKERS] Win32 rename()/unlink() questions +References: <20020919230827.A36505-100000@megazone23.bigpanda.com> <3D8ACA96.80504@mascari.com> +Content-Type: text/plain; charset=us-ascii +Content-Transfer-Encoding: 7bit +X-Virus-Scanned: by AMaViS new-20020517 +Precedence: bulk +Sender: pgsql-hackers-owner@postgresql.org +X-Virus-Scanned: by AMaViS new-20020517 +Status: OR + +Mike Mascari wrote: + +> instead of fopen(). I'm not sure about ME, but I suspect it +> behaves similarly to 95/98. + +I just checked with Katie and the good news (tm) is that the Win32 port +we did here at PeerDirect doesn't support 95/98 and ME anyway. It does +support NT4, 2000 and XP. So don't bother. + + +Jan + +-- + +#======================================================================# +# It's easier to get forgiveness for being wrong than for being right. # +# Let's break this rule - forgive me. # +#================================================== JanWieck@Yahoo.com # + +---------------------------(end of broadcast)--------------------------- +TIP 5: Have you checked our extensive FAQ? + +http://www.postgresql.org/users-lounge/docs/faq.html + +From pgsql-hackers-owner+M29222@postgresql.org Fri Sep 20 11:59:16 2002 +Return-path: +Received: from postgresql.org (postgresql.org [64.49.215.8]) + by candle.pha.pa.us (8.11.6/8.10.1) with ESMTP id g8KFxEE28389 + for ; Fri, 20 Sep 2002 11:59:15 -0400 (EDT) +Received: from localhost (postgresql.org [64.49.215.8]) + by postgresql.org (Postfix) with ESMTP + id 156F6476EFA; Fri, 20 Sep 2002 11:58:59 -0400 (EDT) +Received: from postgresql.org (postgresql.org [64.49.215.8]) + by postgresql.org (Postfix) with SMTP + id 00F87476EE5; Fri, 20 Sep 2002 11:58:56 -0400 (EDT) +Received: from localhost (postgresql.org [64.49.215.8]) + by postgresql.org (Postfix) with ESMTP id 48990475E5E + for ; Fri, 20 Sep 2002 11:57:18 -0400 (EDT) +Received: from corvette.mascari.com (dhcp065-024-158-068.columbus.rr.com [65.24.158.68]) + by postgresql.org (Postfix) with ESMTP id F3EF1475D6E + for ; Fri, 20 Sep 2002 11:57:16 -0400 (EDT) +Received: from mascari.com (ferrari.mascari.com [192.168.2.1]) + by corvette.mascari.com (8.9.3/8.9.3) with ESMTP id LAA20244; + Fri, 20 Sep 2002 11:54:31 -0400 +Message-ID: <3D8B44CC.6070802@mascari.com> +Date: Fri, 20 Sep 2002 11:54:52 -0400 +From: Mike Mascari +User-Agent: Mozilla/5.0 (Windows; U; WinNT4.0; en-US; rv:1.0.1) Gecko/20020823 Netscape/7.0 +X-Accept-Language: en-us, en +MIME-Version: 1.0 +To: Stephan Szabo +cc: Bruce Momjian , + PostgreSQL-development +Subject: Re: [HACKERS] Win32 rename()/unlink() questions +References: <20020920080949.H40440-100000@megazone23.bigpanda.com> +Content-Type: text/plain; charset=us-ascii; format=flowed +Content-Transfer-Encoding: 7bit +X-MailScanner: Found to be clean +X-Virus-Scanned: by AMaViS new-20020517 +Precedence: bulk +Sender: pgsql-hackers-owner@postgresql.org +X-Virus-Scanned: by AMaViS new-20020517 +Status: OR + +Stephan Szabo wrote: +> On Fri, 20 Sep 2002, Mike Mascari wrote: +> +> +>>I think that's a rather poor description. I think it just means +>>that if the file is opened once via CreateFile() with +>>FILE_SHARE_DELETE, then any subsequent CreateFile() calls will +>>fail unless they too have FILE_SHARE_DELETE. In other words, if +>>one of us can delete this file while its open, any of us can. +> +> +> The question is, what happens if two people have the file open +> and one goes and tries to delete it? Can the other still read +> from it? + +Yes. I just tested it and it worked. I'll test Bruce's scenario +as well: + +foo contains: "FOO" +bar contains: "BAR" + +1. Process 1 opens "foo" +2. Process 2 opens "foo" +3. Process 1 calls MoveFile("foo", "foo2"); +4. Process 3 opens "foo" <- Successful? +5. Process 1 calls MoveFile("bar", "foo"); +6. Process 4 opens "foo" <- Successful? +7. Process 1 calls DeleteFile("foo2"); +8. Process 1, 2, 3, 4 all read from their respective handles. + +I think the thing to worry about is a race condition between the +two MoveFile() attempts. A very ugly hack would be to loop in a +CreateFile() in an attempt to open "foo", giving up if the error +is not a NOT EXISTS error code. + +Mike Mascari +mascarm@mascari.com + + +---------------------------(end of broadcast)--------------------------- +TIP 1: subscribe and unsubscribe commands go to majordomo@postgresql.org + +From mascarm@mascari.com Fri Sep 20 11:55:47 2002 +Return-path: +Received: from corvette.mascari.com (dhcp065-024-158-068.columbus.rr.com [65.24.158.68]) + by candle.pha.pa.us (8.11.6/8.10.1) with ESMTP id g8KFthE27924 + for ; Fri, 20 Sep 2002 11:55:45 -0400 (EDT) +Received: from mascari.com (ferrari.mascari.com [192.168.2.1]) + by corvette.mascari.com (8.9.3/8.9.3) with ESMTP id LAA20244; + Fri, 20 Sep 2002 11:54:31 -0400 +Message-ID: <3D8B44CC.6070802@mascari.com> +Date: Fri, 20 Sep 2002 11:54:52 -0400 +From: Mike Mascari +User-Agent: Mozilla/5.0 (Windows; U; WinNT4.0; en-US; rv:1.0.1) Gecko/20020823 Netscape/7.0 +X-Accept-Language: en-us, en +MIME-Version: 1.0 +To: Stephan Szabo +cc: Bruce Momjian , + PostgreSQL-development + +Subject: Re: [HACKERS] Win32 rename()/unlink() questions +References: <20020920080949.H40440-100000@megazone23.bigpanda.com> +Content-Type: text/plain; charset=us-ascii; format=flowed +Content-Transfer-Encoding: 7bit +X-MailScanner: Found to be clean +Status: OR + +Stephan Szabo wrote: +> On Fri, 20 Sep 2002, Mike Mascari wrote: +> +> +>>I think that's a rather poor description. I think it just means +>>that if the file is opened once via CreateFile() with +>>FILE_SHARE_DELETE, then any subsequent CreateFile() calls will +>>fail unless they too have FILE_SHARE_DELETE. In other words, if +>>one of us can delete this file while its open, any of us can. +> +> +> The question is, what happens if two people have the file open +> and one goes and tries to delete it? Can the other still read +> from it? + +Yes. I just tested it and it worked. I'll test Bruce's scenario +as well: + +foo contains: "FOO" +bar contains: "BAR" + +1. Process 1 opens "foo" +2. Process 2 opens "foo" +3. Process 1 calls MoveFile("foo", "foo2"); +4. Process 3 opens "foo" <- Successful? +5. Process 1 calls MoveFile("bar", "foo"); +6. Process 4 opens "foo" <- Successful? +7. Process 1 calls DeleteFile("foo2"); +8. Process 1, 2, 3, 4 all read from their respective handles. + +I think the thing to worry about is a race condition between the +two MoveFile() attempts. A very ugly hack would be to loop in a +CreateFile() in an attempt to open "foo", giving up if the error +is not a NOT EXISTS error code. + +Mike Mascari +mascarm@mascari.com + + +From mascarm@mascari.com Fri Sep 20 12:29:18 2002 +Return-path: +Received: from corvette.mascari.com (dhcp065-024-158-068.columbus.rr.com [65.24.158.68]) + by candle.pha.pa.us (8.11.6/8.10.1) with ESMTP id g8KGTEE01796 + for ; Fri, 20 Sep 2002 12:29:17 -0400 (EDT) +Received: from mascari.com (ferrari.mascari.com [192.168.2.1]) + by corvette.mascari.com (8.9.3/8.9.3) with ESMTP id MAA20365; + Fri, 20 Sep 2002 12:27:10 -0400 +Message-ID: <3D8B4C74.2050708@mascari.com> +Date: Fri, 20 Sep 2002 12:27:32 -0400 +From: Mike Mascari +User-Agent: Mozilla/5.0 (Windows; U; WinNT4.0; en-US; rv:1.0.1) Gecko/20020823 Netscape/7.0 +X-Accept-Language: en-us, en +MIME-Version: 1.0 +To: PostgreSQL-development +cc: Stephan Szabo , + Bruce Momjian + +Subject: Re: [HACKERS] Win32 rename()/unlink() questions +References: <20020920080949.H40440-100000@megazone23.bigpanda.com> <3D8B44CC.6070802@mascari.com> +Content-Type: text/plain; charset=us-ascii; format=flowed +Content-Transfer-Encoding: 7bit +X-MailScanner: Found to be clean +Status: ORr + +I wrote: +> Stephan Szabo wrote: + >> +>> The question is, what happens if two people have the file open +>> and one goes and tries to delete it? Can the other still read +>> from it? +> +> Yes. I just tested it and it worked. I'll test Bruce's scenario as well: +> +> foo contains: "FOO" +> bar contains: "BAR" +> +> 1. Process 1 opens "foo" +> 2. Process 2 opens "foo" +> 3. Process 1 calls MoveFile("foo", "foo2"); +> 4. Process 3 opens "foo" <- Successful? +> 5. Process 1 calls MoveFile("bar", "foo"); +> 6. Process 4 opens "foo" <- Successful? +> 7. Process 1 calls DeleteFile("foo2"); +> 8. Process 1, 2, 3, 4 all read from their respective handles. + +Process 1: "FOO" +Process 2: "FOO" +Process 3: Error - File does not exist +Process 4: "BAR" + +Its interesting in that it allows for Unix-style rename() and +unlink() behavior, but with a race condition. Without Stephan's +two MoveFile() trick and the FILE_SHARE_DELETE flag, however, +the result would be Access Denied. Are the places in the backend +that use rename() and unlink() renaming and unlinking files that +are only opened for a brief moment by other backends? + +Mike Mascari +mascarm@mascari.com + + +From pgsql-hackers-owner+M29230@postgresql.org Fri Sep 20 13:12:45 2002 +Return-path: +Received: from postgresql.org (postgresql.org [64.49.215.8]) + by candle.pha.pa.us (8.11.6/8.10.1) with ESMTP id g8KHChE07387 + for ; Fri, 20 Sep 2002 13:12:44 -0400 (EDT) +Received: from localhost (postgresql.org [64.49.215.8]) + by postgresql.org (Postfix) with ESMTP + id 54F85476F77; Fri, 20 Sep 2002 13:01:57 -0400 (EDT) +Received: from postgresql.org (postgresql.org [64.49.215.8]) + by postgresql.org (Postfix) with SMTP + id 1CC51476F67; Fri, 20 Sep 2002 13:01:39 -0400 (EDT) +Received: from localhost (postgresql.org [64.49.215.8]) + by postgresql.org (Postfix) with ESMTP id B253B476148 + for ; Fri, 20 Sep 2002 12:29:02 -0400 (EDT) +Received: from corvette.mascari.com (dhcp065-024-158-068.columbus.rr.com [65.24.158.68]) + by postgresql.org (Postfix) with ESMTP id 7F8FC476135 + for ; Fri, 20 Sep 2002 12:29:01 -0400 (EDT) +Received: from mascari.com (ferrari.mascari.com [192.168.2.1]) + by corvette.mascari.com (8.9.3/8.9.3) with ESMTP id MAA20365; + Fri, 20 Sep 2002 12:27:10 -0400 +Message-ID: <3D8B4C74.2050708@mascari.com> +Date: Fri, 20 Sep 2002 12:27:32 -0400 +From: Mike Mascari +User-Agent: Mozilla/5.0 (Windows; U; WinNT4.0; en-US; rv:1.0.1) Gecko/20020823 Netscape/7.0 +X-Accept-Language: en-us, en +MIME-Version: 1.0 +To: PostgreSQL-development +cc: Stephan Szabo , + Bruce Momjian +Subject: Re: [HACKERS] Win32 rename()/unlink() questions +References: <20020920080949.H40440-100000@megazone23.bigpanda.com> <3D8B44CC.6070802@mascari.com> +Content-Type: text/plain; charset=us-ascii; format=flowed +Content-Transfer-Encoding: 7bit +X-MailScanner: Found to be clean +X-Virus-Scanned: by AMaViS new-20020517 +Precedence: bulk +Sender: pgsql-hackers-owner@postgresql.org +X-Virus-Scanned: by AMaViS new-20020517 +Status: ORr + +I wrote: +> Stephan Szabo wrote: + >> +>> The question is, what happens if two people have the file open +>> and one goes and tries to delete it? Can the other still read +>> from it? +> +> Yes. I just tested it and it worked. I'll test Bruce's scenario as well: +> +> foo contains: "FOO" +> bar contains: "BAR" +> +> 1. Process 1 opens "foo" +> 2. Process 2 opens "foo" +> 3. Process 1 calls MoveFile("foo", "foo2"); +> 4. Process 3 opens "foo" <- Successful? +> 5. Process 1 calls MoveFile("bar", "foo"); +> 6. Process 4 opens "foo" <- Successful? +> 7. Process 1 calls DeleteFile("foo2"); +> 8. Process 1, 2, 3, 4 all read from their respective handles. + +Process 1: "FOO" +Process 2: "FOO" +Process 3: Error - File does not exist +Process 4: "BAR" + +Its interesting in that it allows for Unix-style rename() and +unlink() behavior, but with a race condition. Without Stephan's +two MoveFile() trick and the FILE_SHARE_DELETE flag, however, +the result would be Access Denied. Are the places in the backend +that use rename() and unlink() renaming and unlinking files that +are only opened for a brief moment by other backends? + +Mike Mascari +mascarm@mascari.com + + +---------------------------(end of broadcast)--------------------------- +TIP 6: Have you searched our list archives? + +http://archives.postgresql.org + +From pgsql-hackers-owner+M29235@postgresql.org Fri Sep 20 13:38:05 2002 +Return-path: +Received: from postgresql.org (postgresql.org [64.49.215.8]) + by candle.pha.pa.us (8.11.6/8.10.1) with ESMTP id g8KHc3E18565 + for ; Fri, 20 Sep 2002 13:38:04 -0400 (EDT) +Received: from localhost (postgresql.org [64.49.215.8]) + by postgresql.org (Postfix) with ESMTP + id D4B2C4764A8; Fri, 20 Sep 2002 13:38:01 -0400 (EDT) +Received: from postgresql.org (postgresql.org [64.49.215.8]) + by postgresql.org (Postfix) with SMTP + id D071B476173; Fri, 20 Sep 2002 13:37:59 -0400 (EDT) +Received: from localhost (postgresql.org [64.49.215.8]) + by postgresql.org (Postfix) with ESMTP id 6DD60476791 + for ; Fri, 20 Sep 2002 13:33:56 -0400 (EDT) +Received: from candle.pha.pa.us (momjian.navpoint.com [207.106.42.251]) + by postgresql.org (Postfix) with ESMTP id C679F476272 + for ; Fri, 20 Sep 2002 13:33:54 -0400 (EDT) +Received: (from pgman@localhost) + by candle.pha.pa.us (8.11.6/8.10.1) id g8KHVRu17060; + Fri, 20 Sep 2002 13:31:27 -0400 (EDT) +From: Bruce Momjian +Message-ID: <200209201731.g8KHVRu17060@candle.pha.pa.us> +Subject: Re: [HACKERS] Win32 rename()/unlink() questions +In-Reply-To: <3D8B4C74.2050708@mascari.com> +To: Mike Mascari +Date: Fri, 20 Sep 2002 13:31:27 -0400 (EDT) +cc: PostgreSQL-development , + Stephan Szabo +X-Mailer: ELM [version 2.4ME+ PL99 (25)] +MIME-Version: 1.0 +Content-Transfer-Encoding: 7bit +Content-Type: text/plain; charset=US-ASCII +X-Virus-Scanned: by AMaViS new-20020517 +Precedence: bulk +Sender: pgsql-hackers-owner@postgresql.org +X-Virus-Scanned: by AMaViS new-20020517 +Status: OR + +Mike Mascari wrote: +> Its interesting in that it allows for Unix-style rename() and +> unlink() behavior, but with a race condition. Without Stephan's +> two MoveFile() trick and the FILE_SHARE_DELETE flag, however, +> the result would be Access Denied. Are the places in the backend +> that use rename() and unlink() renaming and unlinking files that +> are only opened for a brief moment by other backends? + +Yes, those files are only opened for a brief moment. They are not held +open. + +-- + Bruce Momjian | http://candle.pha.pa.us + pgman@candle.pha.pa.us | (610) 359-1001 + + If your life is a hard drive, | 13 Roberts Road + + Christ can be your backup. | Newtown Square, Pennsylvania 19073 + +---------------------------(end of broadcast)--------------------------- +TIP 2: you can get off all lists at once with the unregister command + (send "unregister YourEmailAddressHere" to majordomo@postgresql.org) + +From pgsql-hackers-owner+M29237@postgresql.org Fri Sep 20 13:57:39 2002 +Return-path: +Received: from postgresql.org (postgresql.org [64.49.215.8]) + by candle.pha.pa.us (8.11.6/8.10.1) with ESMTP id g8KHvcE21846 + for ; Fri, 20 Sep 2002 13:57:38 -0400 (EDT) +Received: from localhost (postgresql.org [64.49.215.8]) + by postgresql.org (Postfix) with ESMTP + id 1EC6A4762C8; Fri, 20 Sep 2002 13:57:36 -0400 (EDT) +Received: from postgresql.org (postgresql.org [64.49.215.8]) + by postgresql.org (Postfix) with SMTP + id 321B14760E8; Fri, 20 Sep 2002 13:57:34 -0400 (EDT) +Received: from localhost (postgresql.org [64.49.215.8]) + by postgresql.org (Postfix) with ESMTP id CD7E8476D24 + for ; Fri, 20 Sep 2002 13:54:48 -0400 (EDT) +Received: from candle.pha.pa.us (momjian.navpoint.com [207.106.42.251]) + by postgresql.org (Postfix) with ESMTP id 0C6034762C8 + for ; Fri, 20 Sep 2002 13:54:47 -0400 (EDT) +Received: (from pgman@localhost) + by candle.pha.pa.us (8.11.6/8.10.1) id g8KHrnp21564; + Fri, 20 Sep 2002 13:53:49 -0400 (EDT) +From: Bruce Momjian +Message-ID: <200209201753.g8KHrnp21564@candle.pha.pa.us> +Subject: Re: [HACKERS] Win32 rename()/unlink() questions +In-Reply-To: <3D8B4C74.2050708@mascari.com> +To: Mike Mascari +Date: Fri, 20 Sep 2002 13:53:49 -0400 (EDT) +cc: PostgreSQL-development , + Stephan Szabo +X-Mailer: ELM [version 2.4ME+ PL99 (25)] +MIME-Version: 1.0 +Content-Transfer-Encoding: 7bit +Content-Type: text/plain; charset=US-ASCII +X-Virus-Scanned: by AMaViS new-20020517 +Precedence: bulk +Sender: pgsql-hackers-owner@postgresql.org +X-Virus-Scanned: by AMaViS new-20020517 +Status: OR + +Mike Mascari wrote: +> > foo contains: "FOO" +> > bar contains: "BAR" +> > +> > 1. Process 1 opens "foo" +> > 2. Process 2 opens "foo" +> > 3. Process 1 calls MoveFile("foo", "foo2"); +> > 4. Process 3 opens "foo" <- Successful? +> > 5. Process 1 calls MoveFile("bar", "foo"); +> > 6. Process 4 opens "foo" <- Successful? +> > 7. Process 1 calls DeleteFile("foo2"); +> > 8. Process 1, 2, 3, 4 all read from their respective handles. +> +> Process 1: "FOO" +> Process 2: "FOO" +> Process 3: Error - File does not exist +> Process 4: "BAR" +> +> Its interesting in that it allows for Unix-style rename() and +> unlink() behavior, but with a race condition. Without Stephan's +> two MoveFile() trick and the FILE_SHARE_DELETE flag, however, +> the result would be Access Denied. Are the places in the backend +> that use rename() and unlink() renaming and unlinking files that +> are only opened for a brief moment by other backends? + +I think we are better off looping over +MoveFileEx(MOVEFILE_REPLACE_EXISTING) until the file isn't opened by +anyone. That localizes the changes to rename only and not out to all +the opens. + +The open failure loops when the file isn't there seem much worse. + +I am a little concerned about starving the rename when there is a lot of +activity but I don't see a better solution. + +-- + Bruce Momjian | http://candle.pha.pa.us + pgman@candle.pha.pa.us | (610) 359-1001 + + If your life is a hard drive, | 13 Roberts Road + + Christ can be your backup. | Newtown Square, Pennsylvania 19073 + +---------------------------(end of broadcast)--------------------------- +TIP 3: if posting/reading through Usenet, please send an appropriate +subscribe-nomail command to majordomo@postgresql.org so that your +message can get through to the mailing list cleanly + +From pgsql-hackers-owner+M29214@postgresql.org Fri Sep 20 11:31:33 2002 +Return-path: +Received: from postgresql.org (postgresql.org [64.49.215.8]) + by candle.pha.pa.us (8.11.6/8.10.1) with ESMTP id g8KFVWE25017 + for ; Fri, 20 Sep 2002 11:31:32 -0400 (EDT) +Received: from localhost (postgresql.org [64.49.215.8]) + by postgresql.org (Postfix) with ESMTP + id D2062476F4F; Fri, 20 Sep 2002 11:29:20 -0400 (EDT) +Received: from postgresql.org (postgresql.org [64.49.215.8]) + by postgresql.org (Postfix) with SMTP + id 1A194476EED; Fri, 20 Sep 2002 11:29:18 -0400 (EDT) +Received: from localhost (postgresql.org [64.49.215.8]) + by postgresql.org (Postfix) with ESMTP id 6C448476F71 + for ; Fri, 20 Sep 2002 11:26:26 -0400 (EDT) +Received: from candle.pha.pa.us (momjian.navpoint.com [207.106.42.251]) + by postgresql.org (Postfix) with ESMTP id 2AA7E476F65 + for ; Fri, 20 Sep 2002 11:26:24 -0400 (EDT) +Received: (from pgman@localhost) + by candle.pha.pa.us (8.11.6/8.10.1) id g8KF4rj17150; + Fri, 20 Sep 2002 11:04:53 -0400 (EDT) +From: Bruce Momjian +Message-ID: <200209201504.g8KF4rj17150@candle.pha.pa.us> +Subject: Re: [HACKERS] Win32 rename()/unlink() questionst +In-Reply-To: <3D8ABA3F.6030002@mascari.com> +To: Mike Mascari +Date: Fri, 20 Sep 2002 11:04:53 -0400 (EDT) +cc: Stephan Szabo , + PostgreSQL-development +X-Mailer: ELM [version 2.4ME+ PL99 (25)] +MIME-Version: 1.0 +Content-Transfer-Encoding: 7bit +Content-Type: text/plain; charset=US-ASCII +X-Virus-Scanned: by AMaViS new-20020517 +Precedence: bulk +Sender: pgsql-hackers-owner@postgresql.org +X-Virus-Scanned: by AMaViS new-20020517 +Status: OR + + +It is good that moving the file out of the way works, but it doesn't +completely solve the problem. + +What we have now with Unix rename is ideal: + + 1) old opens continue seeing the old contents + 2) new opens see the new contents + 3) the file always exists under the fixed name + +We have that with MoveFileEx(), but we have to loop over the routine +until is succeeds. If we move the old file out of the way, we loose the +ability to know the file always exists and then we have to loop over +open() until is succeeds. + +I think we may be best just looping on MoveFileEx() until is succeeds. +We do the pg_pwd writes while holding an exclusive lock on pg_shadow so +that will guarantee that no one else will slip an old version of the +file in after we have written it. However, it also prevents pg_shadow +access while we are doing the looping. Yuck. + +--------------------------------------------------------------------------- + +Mike Mascari wrote: +> Stephan Szabo wrote: +> > On Fri, 20 Sep 2002, Mike Mascari wrote: +> >>Bruce Momjian wrote: +> >>>Mike Mascari wrote: +> >>>>Actually, looking at the pg_pwd code, you want to determine a +> >>>>way for: +> >>>> +> >>>>1. Process 1 opens "foo" +> >>>>2. Process 2 opens "foo" +> >>>>3. Process 1 creates "bar" +> >>>>4. Process 1 renames "bar" to "foo" +> >>>>5. Process 2 can continue to read data from the open file handle +> >>>>and get the original "foo" data. +> >>> +> >>> +> >>>Yep, that's it. +> >>> +> >> +> >>So far, MoveFileEx("foo", "bar", MOVEFILE_REPLACE_EXISTING) +> >>returns "Access Denied" when Process 1 attempts the rename. But +> >>I'm continuing to investigate the possibilities... +> > +> > +> > Does a sequence like +> > Process 1 opens "foo" +> > Process 2 opens "foo" +> > Process 1 creates "bar" +> > Process 1 renames "foo" to +> > - where something is generated to not overlap an existing file +> > Process 1 renames "bar" to "foo" +> > Process 2 continues reading +> > let you do the replace and keep reading (at the penalty that +> > you've now got to have a way to know when to remove the +> > various s) +> +> Yes! Indeed that does work. +> +> Mike Mascari +> mascarm@mascari.com +> +> +> ---------------------------(end of broadcast)--------------------------- +> TIP 1: subscribe and unsubscribe commands go to majordomo@postgresql.org +> + +-- + Bruce Momjian | http://candle.pha.pa.us + pgman@candle.pha.pa.us | (610) 359-1001 + + If your life is a hard drive, | 13 Roberts Road + + Christ can be your backup. | Newtown Square, Pennsylvania 19073 + +---------------------------(end of broadcast)--------------------------- +TIP 5: Have you checked our extensive FAQ? + +http://www.postgresql.org/users-lounge/docs/faq.html + +From tgl@sss.pgh.pa.us Fri Sep 20 11:50:26 2002 +Return-path: +Received: from sss.pgh.pa.us (root@[192.204.191.242]) + by candle.pha.pa.us (8.11.6/8.10.1) with ESMTP id g8KFoOE27327 + for ; Fri, 20 Sep 2002 11:50:25 -0400 (EDT) +Received: from sss2.sss.pgh.pa.us (tgl@localhost [127.0.0.1]) + by sss.pgh.pa.us (8.12.5/8.12.5) with ESMTP id g8KFoH5D016740; + Fri, 20 Sep 2002 11:50:17 -0400 (EDT) +To: Bruce Momjian +cc: Mike Mascari , + Stephan Szabo , + PostgreSQL-development +Subject: Re: [HACKERS] Win32 rename()/unlink() questionst +In-Reply-To: <200209201504.g8KF4rj17150@candle.pha.pa.us> +References: <200209201504.g8KF4rj17150@candle.pha.pa.us> +Comments: In-reply-to Bruce Momjian + message dated "Fri, 20 Sep 2002 11:04:53 -0400" +Date: Fri, 20 Sep 2002 11:50:17 -0400 +Message-ID: <16739.1032537017@sss.pgh.pa.us> +From: Tom Lane +Status: ORr + +Bruce Momjian writes: +> I think we may be best just looping on MoveFileEx() until is succeeds. +> We do the pg_pwd writes while holding an exclusive lock on pg_shadow so +> that will guarantee that no one else will slip an old version of the +> file in after we have written it. However, it also prevents pg_shadow +> access while we are doing the looping. Yuck. + +Surely you're not evaluating this on the assumption that the pg_shadow +triggers are the only places that use rename() ? + +I see other places in pgstat and relcache that expect rename() to work +per Unix spec. + + regards, tom lane + +From pgsql-hackers-owner+M29223@postgresql.org Fri Sep 20 12:04:21 2002 +Return-path: +Received: from postgresql.org (postgresql.org [64.49.215.8]) + by candle.pha.pa.us (8.11.6/8.10.1) with ESMTP id g8KG06E28547 + for ; Fri, 20 Sep 2002 12:04:20 -0400 (EDT) +Received: from localhost (postgresql.org [64.49.215.8]) + by postgresql.org (Postfix) with ESMTP + id 0545E476F46; Fri, 20 Sep 2002 11:59:27 -0400 (EDT) +Received: from postgresql.org (postgresql.org [64.49.215.8]) + by postgresql.org (Postfix) with SMTP + id 17069476EA0; Fri, 20 Sep 2002 11:59:24 -0400 (EDT) +Received: from localhost (postgresql.org [64.49.215.8]) + by postgresql.org (Postfix) with ESMTP id DDE66476791 + for ; Fri, 20 Sep 2002 11:57:45 -0400 (EDT) +Received: from candle.pha.pa.us (momjian.navpoint.com [207.106.42.251]) + by postgresql.org (Postfix) with ESMTP id C7B5F4762DE + for ; Fri, 20 Sep 2002 11:57:43 -0400 (EDT) +Received: (from pgman@localhost) + by candle.pha.pa.us (8.11.6/8.10.1) id g8KFu2k28023; + Fri, 20 Sep 2002 11:56:02 -0400 (EDT) +From: Bruce Momjian +Message-ID: <200209201556.g8KFu2k28023@candle.pha.pa.us> +Subject: Re: [HACKERS] Win32 rename()/unlink() questionst +In-Reply-To: <16739.1032537017@sss.pgh.pa.us> +To: Tom Lane +Date: Fri, 20 Sep 2002 11:56:02 -0400 (EDT) +cc: Mike Mascari , + Stephan Szabo , + PostgreSQL-development +X-Mailer: ELM [version 2.4ME+ PL99 (25)] +MIME-Version: 1.0 +Content-Transfer-Encoding: 7bit +Content-Type: text/plain; charset=US-ASCII +X-Virus-Scanned: by AMaViS new-20020517 +Precedence: bulk +Sender: pgsql-hackers-owner@postgresql.org +X-Virus-Scanned: by AMaViS new-20020517 +Status: OR + +Tom Lane wrote: +> Bruce Momjian writes: +> > I think we may be best just looping on MoveFileEx() until is succeeds. +> > We do the pg_pwd writes while holding an exclusive lock on pg_shadow so +> > that will guarantee that no one else will slip an old version of the +> > file in after we have written it. However, it also prevents pg_shadow +> > access while we are doing the looping. Yuck. +> +> Surely you're not evaluating this on the assumption that the pg_shadow +> triggers are the only places that use rename() ? +> +> I see other places in pgstat and relcache that expect rename() to work +> per Unix spec. + +Yes, I know there are others but I think we will need _a_ rename that +works 100% and then replace that in all Win32 rename cases. + +Given what I have seen, I think a single rename with a loop that uses +MoveFileEx() may be our best bet. It is localized, doesn't affect the +open() code, and should work well. The only downside is that under +heavy read activity the loop will loop around a few times but I just +don't see another solution. + +I was initially concerned that the loop in rename could let old renames +update the file overwriting newer contents but I realize now that +rename() itself has the same issue (an old rename could hit in the code +after a newer rename) so in all cases we must already have the proper +locking in place. + +-- + Bruce Momjian | http://candle.pha.pa.us + pgman@candle.pha.pa.us | (610) 359-1001 + + If your life is a hard drive, | 13 Roberts Road + + Christ can be your backup. | Newtown Square, Pennsylvania 19073 + +---------------------------(end of broadcast)--------------------------- +TIP 3: if posting/reading through Usenet, please send an appropriate +subscribe-nomail command to majordomo@postgresql.org so that your +message can get through to the mailing list cleanly +