from the other string-category types; this eliminates a lot of surprising
interpretations that the parser could formerly make when there was no directly
applicable operator.

Create a general mechanism that supports casts to and from the standard string
types (text,varchar,bpchar) for *every* datatype, by invoking the datatype's
I/O functions.  These new casts are assignment-only in the to-string direction,
explicit-only in the other, and therefore should create no surprising behavior.
Remove a bunch of thereby-obsoleted datatype-specific casting functions.

The "general mechanism" is a new expression node type CoerceViaIO that can
actually convert between *any* two datatypes if their external text
representations are compatible.  This is more general than needed for the
immediate feature, but might be useful in plpgsql or other places in future.

This commit does nothing about the issue that applying the concatenation
operator || to non-text types will now fail, often with strange error messages
due to misinterpreting the operator as array concatenation.  Since it often
(not always) worked before, we should either make it succeed or at least give
a more user-friendly error; but details are still under debate.

Peter Eisentraut and Tom Lane

a session regardless of the existence of cached plans. The plancache
only needs to be invalidated so that rules affected by the new setting
will be reflected in the new query plans.

Jan

Many thanks to Heikki Linnakangas <heikki@enterprisedb.com> for his
sharp eyes.

- Fix possible deadlock between UPDATE and VACUUM queries. Bug never was
  observed in 8.2, but it still exist there. HEAD is more sensitive to
  bug after recent "ring" of buffer improvements.
- Fix WAL creation: if parent page is stored as is after split then
  incomplete split isn't removed during replay. This happens rather rare, only
  on large tables with a lot of updates/inserts.
- Fix WAL replay: there was wrong test of XLR_BKP_BLOCK_* for left
  page after deletion of page. That causes wrong rightlink field: it pointed
  to deleted page.
- add checking of match of clearing incomplete split
- cleanup incomplete split list after proceeding

All of this chages doesn't change on-disk storage, so backpatch...
But second point may be an issue for replaying logs from previous version.

to be cases when at least Windows 2000 can do this even though select
just indicated that the socket is readable.

Per report and analysis from Cyril VELTER.

Per failure on buildfarm member baiji and subsequent discussion.

(Possibly release notes material, lest users be confused.)

The --quiet option is now obsolete and without effect in createdb,
createuser, dropdb, dropuser; kept for compatibility but marked for
removal in 8.4.

Progress messages when acting on all databases now go to stdout instead
of stderr, since they are not in fact errors.

Ordered options in reindexdb reference page alphabetically, like in
other programs' pages.

        o -Add a GUC variable to control the tablespace for temporary objects
          and sort files
<
< 	  It could start with a random tablespace from a supplied list and
< 	  cycle through the list.
<

tablespace(s) in which to store temp tables and temporary files.  This is a
list to allow spreading the load across multiple tablespaces (a random list
element is chosen each time a temp object is to be created).  Temp files are
not stored in per-database pgsql_tmp/ directories anymore, but per-tablespace
directories.

Jaime Casanova and Albert Cervera, with review by Bernd Helmle and Tom Lane.

text_time(), and text_timetz().  7.4-vintage bug found by Greg Stark.

< * Allow free-behind capability for large sequential scans, perhaps using
<   posix_fadvise()
> * Allow free-behind capability for large sequential scans to avoid
>   kernel cache spoiling

scan-resistant:

<
< * Allow free-behind capability for large sequential scans, perhaps using
<   posix_fadvise()
<
<   Posix_fadvise() can control both sequential/random file caching and
<   free-behind behavior, but it is unclear how the setting affects other
<   backends that also have the file open, and the feature is not supported
<   on all operating systems.

and most especially for UTF8. Remove unnecessary special cases for bytea
processing and single-byte charset ILIKE.  a ILIKE b is now processed as
lower(a) LIKE lower(b) in all cases. The code is now considerably simpler. All
comparisons are now performed byte-wise, and the text and pattern are also
advanced byte-wise where it is safe to do so - essentially where a wildcard is
not being matched.
Andrew Dunstan, from an original patch by ITAGAKI Takahiro, with ideas from
Tom Lane and Mark Mielke.

wrong data when dumping a bufferload that crosses a component-file boundary.
This probably has not been seen in the wild because (a) component files are
normally 1GB apiece and (b) non-block-aligned buffer usage is relatively
rare.  But it's fairly easy to reproduce a problem if one reduces RELSEG_SIZE
in a test build.  Kudos to Kurt Harriman for spotting the bug.

type. Also, add explicit casts between boolean and text/varchar. Both
of these changes are for conformance with SQL:2003.

Update the regression tests, bump the catversion.

will exit before failing because of conflicting DB usage.  Per discussion,
this seems a good idea to help mask the fact that backend exit takes nonzero
time.  Remove a couple of thereby-obsoleted sleeps in contrib and PL
regression test sequences.

        o Research self-referential UPDATEs that see inconsistent row versions
          in read-committed mode
<
> 	  http://archives.postgresql.org/pgsql-hackers/2007-06/msg00016.php

        o Research self-referential UPDATEs that see inconsistent row versions
          in read-committed mode


http://archives.postgresql.org/pgsql-hackers/2007-05/msg00507.php

selecting power-of-2, rather than prime, numbers of buckets in hash joins.
If the hash functions are doing their jobs properly by making all hash bits
equally random, this is good enough, and it saves expensive integer division
and modulus operations.

delivering a well-randomized hash value.  I got religion on this after
observing that performance of multi-batch hash join degrades terribly if the
higher-order bits of hash values aren't random, as indeed was true for say
hashes of small integer values.  It's now expected and documented that hash
functions should use hash_any or some comparable method to ensure that all
bits of their output are about equally random.

initdb forced because this change invalidates existing hash indexes.  For the
same reason, this isn't back-patchable; the hash join performance problem
will get a band-aid fix in the back branches.

	http://www.ibm.com/developerworks/linux/library/l-clear-code/?ca=dgr-FClnxw01linuxcodetips

EXPLAIN-only operation was a little too short; it skipped initializing the
node's result tuple type, which may be needed depending on what's above the
indexscan node.  Call ExecAssignResultTypeFromTL before exiting.  (For good
luck I moved up the ExecAssignScanProjectionInfo call as well, so that
everything except indexscan-specific initialization will still be done.)
Per example from Grant Finnemore.

index key columns always have the type expected by the index's associated
operators, ie, we add RelabelType nodes when dealing with binary-compatible
index opclasses.  This is needed to get varchar indexes to play nicely with
the new EquivalenceClass machinery, as per recent gripe from Josh Berkus that
CVS HEAD was failing to match a varchar index column to a constant restriction
in the query.

It seems likely that this change will allow removal of a lot of ugly ad-hoc
RelabelType-stripping that the planner has traditionally done while matching
expressions to other expressions, but I'll worry about that some other day.

to implement limited-size "ring" of buffers for VACUUM for GIN & GIST

fail when used in a deferred trigger.  Bug goes back to 8.0; no doubt the
reason it hadn't been noticed is that we've been discouraging use of
user-defined constraint triggers.  Per report from Frank van Vugt.

< * Consider allowing 64-bit integers to be passed by value on 64-bit
<   platforms
> * Consider allowing 64-bit integers and floats to be passed by value on
>   64-bit platforms
>
>   Also change 32-bit floats (float4) to be passed by value at the same
>   time.
>

buffers, rather than blowing out the whole shared-buffer arena.  Aside from
avoiding cache spoliation, this fixes the problem that VACUUM formerly tended
to cause a WAL flush for every page it modified, because we had it hacked to
use only a single buffer.  Those flushes will now occur only once per
ring-ful.  The exact ring size, and the threshold for seqscans to switch into
the ring usage pattern, remain under debate; but the infrastructure seems
done.  The key bit of infrastructure is a new optional BufferAccessStrategy
object that can be passed to ReadBuffer operations; this replaces the former
StrategyHintVacuum API.

This patch also changes the buffer usage-count methodology a bit: we now
advance usage_count when first pinning a buffer, rather than when last
unpinning it.  To preserve the behavior that a buffer's lifetime starts to
decrease when it's released, the clock sweep code is modified to not decrement
usage_count of pinned buffers.

Work not done in this commit: teach GiST and GIN indexes to use the vacuum
BufferAccessStrategy for vacuum-driven fetches.

Original patch by Simon, reworked by Heikki and again by Tom.

< * Consider allowing 64-bit integers to be passed by reference on 64-bit
> * Consider allowing 64-bit integers to be passed by value on 64-bit

>
> * Consider allowing 64-bit integers to be passed by reference on 64-bit
>   platforms

Les Hill

appropriate.

Guillaume Cottenceau