Clean up the messy semantics (not to mention inefficiency) of PageGetTempPage

by splitting it into three functions with better-defined behaviors.

Zdenek Kotala

diff --git a/src/backend/access/gin/gindatapage.c b/src/backend/access/gin/gindatapage.c
index 33ed8928ff51ffaa49ff4ba98260c7185da6690b..7afe36eff5b91b09f093515fc0d4ba22bb2a6e1b 100644 (file)
--- a/src/backend/access/gin/gindatapage.c
+++ b/src/backend/access/gin/gindatapage.c
@@ -8,7 +8,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *                     $PostgreSQL: pgsql/src/backend/access/gin/gindatapage.c,v 1.11 2008/06/19 00:46:03 alvherre Exp $
+ *                     $PostgreSQL: pgsql/src/backend/access/gin/gindatapage.c,v 1.12 2008/11/03 20:47:48 tgl Exp $
  *-------------------------------------------------------------------------
  */
 
@@ -445,7 +445,7 @@ dataSplitPage(GinBtree btree, Buffer lbuf, Buffer rbuf, OffsetNumber off, XLogRe
        char       *ptr;
        OffsetNumber separator;
        ItemPointer bound;
-       Page            lpage = GinPageGetCopyPage(BufferGetPage(lbuf));
+       Page            lpage = PageGetTempPageCopy(BufferGetPage(lbuf));
        ItemPointerData oldbound = *GinDataPageGetRightBound(lpage);
        int                     sizeofitem = GinSizeOfItem(lpage);
        OffsetNumber maxoff = GinPageGetOpaque(lpage)->maxoff;

diff --git a/src/backend/access/gin/ginentrypage.c b/src/backend/access/gin/ginentrypage.c
index ef9c9ba2a403afcb27d6d30daeb07efb9ef73d8f..ec899885ab2de78671f40c18373ca3e02a73f35c 100644 (file)
--- a/src/backend/access/gin/ginentrypage.c
+++ b/src/backend/access/gin/ginentrypage.c
@@ -8,7 +8,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *                     $PostgreSQL: pgsql/src/backend/access/gin/ginentrypage.c,v 1.17 2008/07/11 21:06:29 tgl Exp $
+ *                     $PostgreSQL: pgsql/src/backend/access/gin/ginentrypage.c,v 1.18 2008/11/03 20:47:48 tgl Exp $
  *-------------------------------------------------------------------------
  */
 
@@ -458,7 +458,7 @@ entrySplitPage(GinBtree btree, Buffer lbuf, Buffer rbuf, OffsetNumber off, XLogR
                                leftrightmost = NULL;
        static ginxlogSplit data;
        Page            page;
-       Page            lpage = GinPageGetCopyPage(BufferGetPage(lbuf));
+       Page            lpage = PageGetTempPageCopy(BufferGetPage(lbuf));
        Page            rpage = BufferGetPage(rbuf);
        Size            pageSize = PageGetPageSize(lpage);
 

diff --git a/src/backend/access/gin/ginutil.c b/src/backend/access/gin/ginutil.c
index 587add92e97513234dbfcf519c6c3c0d032da64f..c111c060392cd765fbf8ef920bc1393f88469efe 100644 (file)
--- a/src/backend/access/gin/ginutil.c
+++ b/src/backend/access/gin/ginutil.c
@@ -8,7 +8,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *                     $PostgreSQL: pgsql/src/backend/access/gin/ginutil.c,v 1.17 2008/09/30 10:52:10 heikki Exp $
+ *                     $PostgreSQL: pgsql/src/backend/access/gin/ginutil.c,v 1.18 2008/11/03 20:47:48 tgl Exp $
  *-------------------------------------------------------------------------
  */
 
@@ -310,21 +310,6 @@ extractEntriesSU(GinState *ginstate, OffsetNumber attnum, Datum value, int32 *ne
        return entries;
 }
 
-/*
- * It's analog of PageGetTempPage(), but copies whole page
- */
-Page
-GinPageGetCopyPage(Page page)
-{
-       Size            pageSize = PageGetPageSize(page);
-       Page            tmppage;
-
-       tmppage = (Page) palloc(pageSize);
-       memcpy(tmppage, page, pageSize);
-
-       return tmppage;
-}
-
 Datum
 ginoptions(PG_FUNCTION_ARGS)
 {

diff --git a/src/backend/access/gin/ginvacuum.c b/src/backend/access/gin/ginvacuum.c
index ae6459c9fac555a1ca489f5266c67672e6ae29b5..c49926c3fd2a7bc01ebed7c1756694d320f455d6 100644 (file)
--- a/src/backend/access/gin/ginvacuum.c
+++ b/src/backend/access/gin/ginvacuum.c
@@ -8,7 +8,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *                     $PostgreSQL: pgsql/src/backend/access/gin/ginvacuum.c,v 1.24 2008/10/31 15:04:59 heikki Exp $
+ *                     $PostgreSQL: pgsql/src/backend/access/gin/ginvacuum.c,v 1.25 2008/11/03 20:47:48 tgl Exp $
  *-------------------------------------------------------------------------
  */
 
@@ -546,7 +546,7 @@ ginVacuumEntryPage(GinVacuumState *gvs, Buffer buffer, BlockNumber *roots, uint3
                                         * On first difference we create temporary page in memory
                                         * and copies content in to it.
                                         */
-                                       tmppage = GinPageGetCopyPage(origpage);
+                                       tmppage = PageGetTempPageCopy(origpage);
 
                                        if (newN > 0)
                                        {

diff --git a/src/backend/access/gist/gist.c b/src/backend/access/gist/gist.c
index 2f75c3fa2a3065256aa7bce1597193dcc930f982..e1f068ee7bcd7abdb40bd9b3375f94af94096390 100644 (file)
--- a/src/backend/access/gist/gist.c
+++ b/src/backend/access/gist/gist.c
@@ -8,7 +8,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *       $PostgreSQL: pgsql/src/backend/access/gist/gist.c,v 1.152 2008/09/30 10:52:10 heikki Exp $
+ *       $PostgreSQL: pgsql/src/backend/access/gist/gist.c,v 1.153 2008/11/03 20:47:48 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -343,7 +343,7 @@ gistplacetopage(GISTInsertState *state, GISTSTATE *giststate)
                         * we must create temporary page to operate
                         */
                        dist->buffer = state->stack->buffer;
-                       dist->page = PageGetTempPage(BufferGetPage(dist->buffer), sizeof(GISTPageOpaqueData));
+                       dist->page = PageGetTempPageCopySpecial(BufferGetPage(dist->buffer));
 
                        /* clean all flags except F_LEAF */
                        GistPageGetOpaque(dist->page)->flags = (is_leaf) ? F_LEAF : 0;

diff --git a/src/backend/access/gist/gistvacuum.c b/src/backend/access/gist/gistvacuum.c
index 80710ae7368f3c2ecc091d57ba48168e93d3c3e9..d933fea25b2e8169ff023c20e068f6af03bc3722 100644 (file)
--- a/src/backend/access/gist/gistvacuum.c
+++ b/src/backend/access/gist/gistvacuum.c
@@ -8,7 +8,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *       $PostgreSQL: pgsql/src/backend/access/gist/gistvacuum.c,v 1.39 2008/10/31 15:04:59 heikki Exp $
+ *       $PostgreSQL: pgsql/src/backend/access/gist/gistvacuum.c,v 1.40 2008/11/03 20:47:48 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -144,18 +144,6 @@ gistDeleteSubtree(GistVacuum *gv, BlockNumber blkno)
        UnlockReleaseBuffer(buffer);
 }
 
-static Page
-GistPageGetCopyPage(Page page)
-{
-       Size            pageSize = PageGetPageSize(page);
-       Page            tmppage;
-
-       tmppage = (Page) palloc(pageSize);
-       memcpy(tmppage, page, pageSize);
-
-       return tmppage;
-}
-
 static ArrayTuple
 vacuumSplitPage(GistVacuum *gv, Page tempPage, Buffer buffer, IndexTuple *addon, int curlenaddon)
 {
@@ -325,7 +313,7 @@ gistVacuumUpdate(GistVacuum *gv, BlockNumber blkno, bool needunion)
                addon = (IndexTuple *) palloc(sizeof(IndexTuple) * lenaddon);
 
                /* get copy of page to work */
-               tempPage = GistPageGetCopyPage(page);
+               tempPage = PageGetTempPageCopy(page);
 
                for (i = FirstOffsetNumber; i <= maxoff; i = OffsetNumberNext(i))
                {

diff --git a/src/backend/access/nbtree/nbtinsert.c b/src/backend/access/nbtree/nbtinsert.c
index 01e1ea494489cb69bd1f8d0e5c3c0e884be0d541..6842d5e8c9138a65e6512c548f9ab5b2ea502529 100644 (file)
--- a/src/backend/access/nbtree/nbtinsert.c
+++ b/src/backend/access/nbtree/nbtinsert.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *       $PostgreSQL: pgsql/src/backend/access/nbtree/nbtinsert.c,v 1.167 2008/06/11 08:38:56 heikki Exp $
+ *       $PostgreSQL: pgsql/src/backend/access/nbtree/nbtinsert.c,v 1.168 2008/11/03 20:47:48 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -793,7 +793,7 @@ _bt_split(Relation rel, Buffer buf, OffsetNumber firstright,
 
        rbuf = _bt_getbuf(rel, P_NEW, BT_WRITE);
        origpage = BufferGetPage(buf);
-       leftpage = PageGetTempPage(origpage, sizeof(BTPageOpaqueData));
+       leftpage = PageGetTempPage(origpage);
        rightpage = BufferGetPage(rbuf);
 
        _bt_pageinit(leftpage, BufferGetPageSize(buf));

diff --git a/src/backend/storage/page/bufpage.c b/src/backend/storage/page/bufpage.c
index abfc569399ebd1990094ae00a869ac78f52e33b5..3faae011b37c5a972d1b988f6668caa6933fac90 100644 (file)
--- a/src/backend/storage/page/bufpage.c
+++ b/src/backend/storage/page/bufpage.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *       $PostgreSQL: pgsql/src/backend/storage/page/bufpage.c,v 1.80 2008/07/13 21:50:04 tgl Exp $
+ *       $PostgreSQL: pgsql/src/backend/storage/page/bufpage.c,v 1.81 2008/11/03 20:47:48 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -254,28 +254,59 @@ PageAddItem(Page page,
 
 /*
  * PageGetTempPage
- *             Get a temporary page in local memory for special processing
+ *             Get a temporary page in local memory for special processing.
+ *             The returned page is not initialized at all; caller must do that.
  */
 Page
-PageGetTempPage(Page page, Size specialSize)
+PageGetTempPage(Page page)
+{
+       Size            pageSize;
+       Page            temp;
+
+       pageSize = PageGetPageSize(page);
+       temp = (Page) palloc(pageSize);
+
+       return temp;
+}
+
+/*
+ * PageGetTempPageCopy
+ *             Get a temporary page in local memory for special processing.
+ *             The page is initialized by copying the contents of the given page.
+ */
+Page
+PageGetTempPageCopy(Page page)
 {
        Size            pageSize;
        Page            temp;
-       PageHeader      thdr;
 
        pageSize = PageGetPageSize(page);
        temp = (Page) palloc(pageSize);
-       thdr = (PageHeader) temp;
 
-       /* copy old page in */
        memcpy(temp, page, pageSize);
 
-       /* set high, low water marks */
-       thdr->pd_lower = SizeOfPageHeaderData;
-       thdr->pd_upper = pageSize - MAXALIGN(specialSize);
+       return temp;
+}
+
+/*
+ * PageGetTempPageCopySpecial
+ *             Get a temporary page in local memory for special processing.
+ *             The page is PageInit'd with the same special-space size as the
+ *             given page, and the special space is copied from the given page.
+ */
+Page
+PageGetTempPageCopySpecial(Page page)
+{
+       Size            pageSize;
+       Page            temp;
+
+       pageSize = PageGetPageSize(page);
+       temp = (Page) palloc(pageSize);
 
-       /* clear out the middle */
-       MemSet((char *) temp + thdr->pd_lower, 0, thdr->pd_upper - thdr->pd_lower);
+       PageInit(temp, pageSize, PageGetSpecialSize(page));
+       memcpy(PageGetSpecialPointer(temp),
+                  PageGetSpecialPointer(page),
+                  PageGetSpecialSize(page));
 
        return temp;
 }

diff --git a/src/include/access/gin.h b/src/include/access/gin.h
index 57cb8a345a76294c7b198df093734933ae1da29e..51510585143ed09ac929c84ec1e0bdda78c854dd 100644 (file)
--- a/src/include/access/gin.h
+++ b/src/include/access/gin.h
@@ -4,7 +4,7 @@
  *
  *     Copyright (c) 2006-2008, PostgreSQL Global Development Group
  *
- *     $PostgreSQL: pgsql/src/include/access/gin.h,v 1.25 2008/10/20 13:39:44 teodor Exp $
+ *     $PostgreSQL: pgsql/src/include/access/gin.h,v 1.26 2008/11/03 20:47:49 tgl Exp $
  *--------------------------------------------------------------------------
  */
 
@@ -246,7 +246,6 @@ extern int  compareAttEntries(GinState *ginstate, OffsetNumber attnum_a, Datum a,
 extern Datum *extractEntriesS(GinState *ginstate, OffsetNumber attnum, Datum value,
                                int32 *nentries, bool *needUnique);
 extern Datum *extractEntriesSU(GinState *ginstate, OffsetNumber attnum, Datum value, int32 *nentries);
-extern Page GinPageGetCopyPage(Page page);
 
 extern Datum gin_index_getattr(GinState *ginstate, IndexTuple tuple);
 extern OffsetNumber gintuple_get_attrnum(GinState *ginstate, IndexTuple tuple);

diff --git a/src/include/storage/bufpage.h b/src/include/storage/bufpage.h
index 5a8c2b0d307ba25fa8a137678eb7f4935a52f80b..a5b88e78dfbe0a2888ee205e870f1cb398d7d0cf 100644 (file)
--- a/src/include/storage/bufpage.h
+++ b/src/include/storage/bufpage.h
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/storage/bufpage.h,v 1.83 2008/07/14 03:22:32 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/storage/bufpage.h,v 1.84 2008/11/03 20:47:49 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -362,7 +362,9 @@ extern void PageInit(Page page, Size pageSize, Size specialSize);
 extern bool PageHeaderIsValid(PageHeader page);
 extern OffsetNumber PageAddItem(Page page, Item item, Size size,
                        OffsetNumber offsetNumber, bool overwrite, bool is_heap);
-extern Page PageGetTempPage(Page page, Size specialSize);
+extern Page PageGetTempPage(Page page);
+extern Page PageGetTempPageCopy(Page page);
+extern Page PageGetTempPageCopySpecial(Page page);
 extern void PageRestoreTempPage(Page tempPage, Page oldPage);
 extern void PageRepairFragmentation(Page page);
 extern Size PageGetFreeSpace(Page page);