Tom Lane [Wed, 12 Mar 2008 20:11:46 +0000 (20:11 +0000)]
Fix LISTEN/NOTIFY race condition reported by Laurent Birtz, by postponing
pg_listener modifications commanded by LISTEN and UNLISTEN until the end
of the current transaction. This allows us to hold the ExclusiveLock on
pg_listener until after commit, with no greater risk of deadlock than there
was before. Aside from fixing the race condition, this gets rid of a
truly ugly kludge that was there before, namely having to ignore
HeapTupleBeingUpdated failures during NOTIFY. There is a small potential
incompatibility, which is that if a transaction issues LISTEN or UNLISTEN
and then looks into pg_listener before committing, it won't see any resulting
row insertion or deletion, where before it would have. It seems unlikely
that anyone would be depending on that, though.
This patch also disallows LISTEN and UNLISTEN inside a prepared transaction.
That case had some pretty undesirable properties already, such as possibly
allowing pg_listener entries to be made for PIDs no longer present, so
disallowing it seems like a better idea than trying to maintain the behavior.
Bruce Momjian [Wed, 12 Mar 2008 18:33:54 +0000 (18:33 +0000)]
Add for Win32 TODO:
> o Diagnose problem where shared memory can sometimes not be
> attached by postmaster children
>
> http://archives.postgresql.org/pgsql-general/2007-08/msg01377.php
>
Bruce Momjian [Wed, 12 Mar 2008 01:48:08 +0000 (01:48 +0000)]
Add URL for:
* Improve speed with indexes
For large table adjustments during VACUUM FULL, it is faster to cluster
or reindex rather than update the index. Also, index updates can bloat
the index.
Bruce Momjian [Tue, 11 Mar 2008 22:31:02 +0000 (22:31 +0000)]
Add to pl/pgsql:
>
> o Improve logic of determining if an identifier is a a
> variable or column name
>
> http://archives.postgresql.org/pgsql-hackers/2007-07/msg00436.php
Bruce Momjian [Tue, 11 Mar 2008 20:46:20 +0000 (20:46 +0000)]
< * Consider adding buffers the BGW finds reusable to the free list
> * Consider adding buffers the background writer finds reusable to the
> free list
>
> * Consider wither increasing BM_MAX_USAGE_COUNT improves performance
>
> http://archives.postgresql.org/pgsql-hackers/2007-06/msg01007.php
Tom Lane [Tue, 11 Mar 2008 20:20:35 +0000 (20:20 +0000)]
Make TransactionIdIsInProgress check transam.c's single-item XID status cache
before it goes groveling through the ProcArray. In situations where the same
recently-committed transaction ID is checked repeatedly by tqual.c, this saves
a lot of shared-memory searches. And it's cheap enough that it shouldn't
hurt noticeably when it doesn't help.
Concept and patch by Simon, some minor tweaking and comment-cleanup by Tom.
Bruce Momjian [Tue, 11 Mar 2008 19:44:39 +0000 (19:44 +0000)]
Add:
>
> * Change memory allocation for multi-byte functions so memory is
> allocated inside conversion functions
>
> Currently we preallocate memory based on worst-case usage.
Bruce Momjian [Tue, 11 Mar 2008 19:34:12 +0000 (19:34 +0000)]
Add another URL for:
* Consider increasing the number of default statistics target, and
reduce statistics target overhead
Also consider having a larger statistics target for indexed columns
and expression indexes
<
> http://archives.postgresql.org/pgsql-general/2007-06/msg00542.php
Bruce Momjian [Tue, 11 Mar 2008 19:32:03 +0000 (19:32 +0000)]
Add URL for:
* Consider increasing the number of default statistics target, and
reduce statistics target overhead
Also consider having a larger statistics target for indexed columns
and expression indexes
> http://archives.postgresql.org/pgsql-general/2007-05/msg01228.php
>
Bruce Momjian [Tue, 11 Mar 2008 18:30:50 +0000 (18:30 +0000)]
Add:
>
> * Consider increasing the number of default statistics target, and
> reduce statistics target overhead
>
> Also consider having a larger statistics target for indexed columns
> and expression indexes
Bruce Momjian [Tue, 11 Mar 2008 15:45:05 +0000 (15:45 +0000)]
Add:
>
> * Consider adding buffers the BGW finds reusable to the free list
>
> http://archives.postgresql.org/pgsql-hackers/2007-04/msg00781.php
>
> * Automatically tune bgwriter_delay based on activity rather then using a
> fixed interval
>
> http://archives.postgresql.org/pgsql-hackers/2007-04/msg00781.php
Tom Lane [Mon, 10 Mar 2008 21:50:16 +0000 (21:50 +0000)]
Use -fwrapv in CFLAGS if we are using a version of gcc that accepts this flag.
This prevents compiler optimizations that assume overflow won't occur, which
breaks numerous overflow tests that we need to have working. It is known
that gcc 4.3 causes problems and possible that 4.1 does. Per my proposal
of some time ago and a recent report from Kris Jurka.
Backpatch as far as 8.0, which is as far as the patch conveniently goes.
7.x was pretty short of overflow tests anyway, so it may not matter there,
even assuming that anyone cares whether 7.x builds on recent gcc.
Tom Lane [Mon, 10 Mar 2008 20:06:27 +0000 (20:06 +0000)]
Provide a build-time option to store large relations as single files, rather
than dividing them into 1GB segments as has been our longtime practice. This
requires working support for large files in the operating system; at least for
the time being, it won't be the default.
Magnus Hagander [Mon, 10 Mar 2008 12:55:13 +0000 (12:55 +0000)]
Implement enum type for guc parameters, and convert a couple of existing
variables to it. More need to be converted, but I wanted to get this in
before it conflicts with too much...
Other than just centralising the text-to-int conversion for parameters,
this allows the pg_settings view to contain a list of available options
and allows an error hint to show what values are allowed.
Tom Lane [Mon, 10 Mar 2008 12:39:23 +0000 (12:39 +0000)]
Document and enforce that the usable range of setseed() arguments is
-1 to 1, not 0 to 1. The actual behavior for values within this range
does not change. Kris Jurka
Tom Lane [Mon, 10 Mar 2008 03:22:29 +0000 (03:22 +0000)]
Increase the default value of log_min_messages to WARNING, so that
NOTICE-grade messages are not logged by default. Per pgsql-hackers
discussion back on 21-Nov-2007.
Tom Lane [Mon, 10 Mar 2008 02:04:10 +0000 (02:04 +0000)]
Reduce memory consumption during VACUUM of large relations, by using
FSMPageData (6 bytes) instead of PageFreeSpaceInfo (8 or 16 bytes)
for the temporary array of page-free-space information.
Tom Lane [Mon, 10 Mar 2008 01:23:04 +0000 (01:23 +0000)]
Fix pgbench's getrand() function so that min and max have approximately
the same chance of being selected as do numbers between them. Problem
noted by Greg Stark; fix by Alexey Klyukin.
Tom Lane [Sun, 9 Mar 2008 04:56:28 +0000 (04:56 +0000)]
Remove postmaster.c's check that NBuffers is at least twice MaxBackends.
With the addition of multiple autovacuum workers, our choices were to delete
the check, document the interaction with autovacuum_max_workers, or complicate
the check to try to hide that interaction. Since this restriction has never
been adequate to ensure backends can't run out of pinnable buffers, it doesn't
really have enough excuse to live to justify the second or third choices.
Per discussion of a complaint from Andreas Kling (see also bug #3888).
This commit also removes several documentation references to this restriction,
but I'm not sure I got them all.
Tom Lane [Sun, 9 Mar 2008 00:32:09 +0000 (00:32 +0000)]
Change patternsel() so that instead of switching from a pure
pattern-examination heuristic method to purely histogram-driven selectivity at
histogram size 100, we compute both estimates and use a weighted average.
The weight put on the heuristic estimate decreases linearly with histogram
size, dropping to zero for 100 or more histogram entries.
Likewise in ltreeparentsel(). After a patch by Greg Stark, though I
reorganized the logic a bit to give the caller of histogram_selectivity()
more control.
Tom Lane [Sat, 8 Mar 2008 22:41:38 +0000 (22:41 +0000)]
Modify prefix_selectivity() so that it will never estimate the selectivity
of the generated range condition var >= 'foo' AND var < 'fop' as being less
than what eqsel() would estimate for var = 'foo'. This is intuitively
reasonable and it gets rid of the need for some entirely ad-hoc coding we
formerly used to reject bogus estimates. The basic problem here is that
if the prefix is more than a few characters long, the two boundary values
are too close together to be distinguishable by comparison to the column
histogram, resulting in a selectivity estimate of zero, which is often
not very sane. Change motivated by an example from Peter Eisentraut.
Arguably this is a bug fix, but I'll refrain from back-patching it
for the moment.
Tom Lane [Sat, 8 Mar 2008 21:57:59 +0000 (21:57 +0000)]
Refactor heap_page_prune so that instead of changing item states on-the-fly,
it accumulates the set of changes to be made and then applies them. It had
to accumulate the set of changes anyway to prepare a WAL record for the
pruning action, so this isn't an enormous change; the only new complexity is
to not doubly mark tuples that are visited twice in the scan. The main
advantage is that we can substantially reduce the scope of the critical
section in which the changes are applied, thus avoiding PANIC in foreseeable
cases like running out of memory in inval.c. A nice secondary advantage is
that it is now far clearer that WAL replay will actually do the same thing
that the original pruning did.
This commit doesn't do anything about the open problem that
CacheInvalidateHeapTuple doesn't have the right semantics for a CTID change
caused by collapsing out a redirect pointer. But whatever we do about that,
it'll be a good idea to not do it inside a critical section.
Andrew Dunstan [Sat, 8 Mar 2008 01:16:26 +0000 (01:16 +0000)]
Improve efficiency of attribute scanning in CopyReadAttributesCSV.
The loop is split into two parts, inside quotes, and outside quotes, saving some instructions in both parts.
Tom Lane [Sat, 8 Mar 2008 01:09:36 +0000 (01:09 +0000)]
Improve pglz_decompress() so that it cannot clobber memory beyond the
available output buffer when presented with corrupt input. Some testing
suggests that this slows the decompression loop about 1%, which seems an
acceptable price to pay for more robustness. (Curiously, the penalty
seems to be *less* on not-very-compressible data, which I didn't expect
since the overhead per output byte ought to be more in the literal-bytes
path.)
Patch from Zdenek Kotala. I fixed a corner case and did some renaming
of variables to make the routine more readable.
Tom Lane [Fri, 7 Mar 2008 23:20:21 +0000 (23:20 +0000)]
This patch addresses some issues in TOAST compression strategy that
were discussed last year, but we felt it was too late in the 8.3 cycle to
change the code immediately. Specifically, the patch:
* Reduces the minimum datum size to be considered for compression from
256 to 32 bytes, as suggested by Greg Stark.
* Increases the required compression rate for compressed storage from
20% to 25%, again per Greg's suggestion.
* Replaces force_input_size (size above which compression is forced)
with a maximum size to be considered for compression. It was agreed
that allowing large inputs to escape the minimum-compression-rate
requirement was not bright, and that indeed we'd rather have a knob
that acted in the other direction. I set this value to 1MB for the
moment, but it could use some performance studies to tune it.
* Adds an early-failure path to the compressor as suggested by Jan:
if it's been unable to find even one compressible substring in the
first 1KB (parameterizable), assume we're looking at incompressible
input and give up. (Possibly this logic can be improved, but I'll
commit it as-is for now.)
* Improves the toasting heuristics so that when we have very large
fields with attstorage 'x' or 'e', we will push those out to toast
storage before considering inline compression of shorter fields.
This also responds to a suggestion of Greg's, though my original
proposal for a solution was a bit off base because it didn't fix
the problem for large 'e' fields.
There was some discussion in the earlier threads of exposing some
of the compression knobs to users, perhaps even on a per-column
basis. I have not done anything about that here. It seems to me
that if we are changing around the parameters, we'd better get some
experience and be sure we are happy with the design before we set
things in stone by providing user-visible knobs.
Bruce Momjian [Fri, 7 Mar 2008 20:38:59 +0000 (20:38 +0000)]
Add:
>
> * Add a function like pg_get_indexdef() that report more detailed index
> information
>
> http://archives.postgresql.org/pgsql-bugs/2007-12/msg00166.php
>
Bruce Momjian [Fri, 7 Mar 2008 20:22:25 +0000 (20:22 +0000)]
Add:
>
>
> o Prevent autovacuum from running if an old transaction is still
> running from the last vacuum
>
> http://archives.postgresql.org/pgsql-hackers/2007-11/msg00899.php
>
Bruce Momjian [Fri, 7 Mar 2008 19:03:39 +0000 (19:03 +0000)]
Add item:
> o Store per-table autovacuum settings in pg_class.reloptions.
>
> http://archives.postgresql.org/pgsql-hackers/2007-02/msg01440.php
> http://archives.postgresql.org/pgsql-hackers/2008-01/msg00724.php
Tom Lane [Fri, 7 Mar 2008 15:59:03 +0000 (15:59 +0000)]
Change hashscan.c to keep its list of active hash index scans in
TopMemoryContext, rather than scattered through executor per-query contexts.
This poses no danger of memory leak since the ResourceOwner mechanism
guarantees release of no-longer-needed items. It is needed because the
per-query context might already be released by the time we try to clean up
the hash scan list. Report by ykhuang, diagnosis by Heikki.
Back-patch to 8.0, where the ResourceOwner-based cleanup was introduced.
The given test case does not fail before 8.2, probably because we rearranged
transaction abort processing somehow; but this coding is undoubtedly risky
so I'll patch 8.0 and 8.1 anyway.
Bruce Momjian [Fri, 7 Mar 2008 14:57:39 +0000 (14:57 +0000)]
Add:
>
> * Add comments on system tables/columns using the information in
> catalogs.sgml
>
> Ideally the information would be pulled from the SGML file
> automatically.
>
Teodor Sigaev [Fri, 7 Mar 2008 14:30:20 +0000 (14:30 +0000)]
Fix memory arrangement of tsquery after removing stop words. It causes
a unused memory holes in tsquery.
Per report by Richard Huxton <dev@archonet.com>.
It was working well because in fact tsquery->size is not used for any
kind of operation except comparing tsqueries. So, in HEAD it's enough to
fix to_tsquery function, but for previous version it's needed to
remove optimization in CompareTSQ to prevent requirement of renew all
stored tsquery.
Bruce Momjian [Fri, 7 Mar 2008 00:10:13 +0000 (00:10 +0000)]
Add:
> o Have \d show foreign keys that reference a table's primary key
>
> http://archives.postgresql.org/pgsql-hackers/2007-04/msg00424.php
>
> o Have \d show child tables that inherit from the specified parent
Bruce Momjian [Thu, 6 Mar 2008 22:09:43 +0000 (22:09 +0000)]
Add URLs for:
* Consider compressing indexes by storing key values duplicated in
several rows as a single index entry
>
> http://archives.postgresql.org/pgsql-hackers/2006-12/msg00341.php
> http://archives.postgresql.org/pgsql-hackers/2007-02/msg01264.php
> http://archives.postgresql.org/pgsql-hackers/2007-03/msg00465.php
>
Bruce Momjian [Thu, 6 Mar 2008 21:25:50 +0000 (21:25 +0000)]
Add:
>
> * Allow client certificate names to be checked against the client
> hostname
>
> This is already implemented in
> libpq/fe-secure.c::verify_peer_name_matches_certificate() but the code
> is commented out.
Bruce Momjian [Thu, 6 Mar 2008 17:19:38 +0000 (17:19 +0000)]
Add:
> * Prevent malicious functions from being executed with the permissions
> of unsuspecting users
>
> Index functions are safe, so VACUUM and ANALYZE are safe too.
> Triggers, CHECK and DEFAULT expressions, and rules are still vulnerable.
> http://archives.postgresql.org/pgsql-hackers/2008-01/msg00268.php
Bruce Momjian [Thu, 6 Mar 2008 03:18:19 +0000 (03:18 +0000)]
Add:
>
> o Have CONSTRAINT cname NOT NULL preserve the contraint name
>
> Right now pg_attribute.attnotnull records the NOT NULL status
> of the column, but does not record the contraint name
>
projects / postgresql / log