>
> * Allow heap reuse of UPDATEd rows if old and new versions are on the
>   same heap page?
>
>   This is possible for same-page updates because a single index row
>   can point to both old and new values.
>   http://archives.postgresql.org/pgsql-hackers/2006-06/msg01305.php

and there was some question about its copyright status.

backup history file.  Bug introduced by the 8.1 change to make pg_stop_backup
delete older history files.  Per report from Masao Fujii.

setup_win32_locks() call formerly was, to ensure that cancelConnLock is
valid when it needs to be.  Per Yoshiyuki Asaba.

aggregates.  We just disallowed that, and AFAICS there should be no other
cases where direct (non-aggregated) references to input columns are allowed
in a query with aggregation and no GROUP BY.

This is disallowed by the SQL spec because it doesn't have any very sensible
interpretation.  Historically Postgres has allowed it but behaved strangely.
As of PG 8.1 a server crash is possible if the MIN/MAX index optimization gets
applied; rather than try to "fix" that, it seems best to just enforce the
spec restriction.  Per report from Josh Drake and Alvaro Herrera.

Eliminate a gratuitously different wording of the 'cannot use aggregate function in check constraint' error message.

  initially be 0. This is needed as a previous ABORT might have wiped out
  an automatically opened transaction without maintaining the cursor count.
- Fix regression test expected file for the correct ERROR message, which
  we now get given the above bug fix.

GetVariable() and be consistent about treatment of the list header.
Motivated by noticing strspn() taking an unreasonable percentage of
runtime --- the call removed from GetVariable() was the only one that
could be in a high-usage path ...

Added missing error handling in a few functions in ecpglib

changing semantics too much.  statement_timestamp is now set immediately
upon receipt of a client command message, and the various places that used
to do their own gettimeofday() calls to mark command startup are referenced
to that instead.  I have also made stats_command_string use that same
value for pg_stat_activity.query_start for both the command itself and
its eventual replacement by <IDLE> or <idle in transaction>.  There was
some debate about that, but no argument that seemed convincing enough to
justify an extra gettimeofday() call.

libpq/md5.h, so that there's a clear separation between backend-only
definitions and shared frontend/backend definitions.  (Turns out this
is reversing a bad decision from some years ago...)  Fix up references
to crypt.h as needed.  I looked into moving the code into src/port, but
the headers in src/include/libpq are sufficiently intertwined that it
seems more work than it's worth to do that.

functions.

<joachim.wieland@credativ.de>

current commands; instead, store current-status information in shared
memory.  This substantially reduces the overhead of stats_command_string
and also ensures that pg_stat_activity is fully up to date at all times.
Per my recent proposal.

for it.  Hopefully will fix core dump evidenced by some buildfarm members
since fadvise patch went in.  The actual definition of the function is not
ABI-compatible with compiler's default assumption in the absence of any
declaration, so it's clearly unsafe to try to call it without seeing a
declaration.

Darwin's libedit; per my proposal last August.  Also, suppress cast-away-
const warnings.

We have once or twice seen failures suggesting that control didn't get
to the exception block before the timeout elapsed, which is unlikely
but not impossible in a parallel regression test (with a dozen other
backends competing for cycles).  This change doesn't completely prevent
the problem of course, but it should reduce the probability enough that
we don't see it anymore.  Per buildfarm results.

symlink is kept for now for compatibility.  To call single-user mode, use
postgres --single.

SQLSTATEs, fix some documentation problems.

leading zeroes from the SQLSTATE codes.  They're strings, people,
not numbers.

docs for DROP ... IF EXISTS for the following cases:
  language, tablespace, trigger, rule, opclass, function, aggregate. operator, and cast.

> 		o Allow PL/python to composite types and result sets
> 		  once buggy assert-enabled versions of python can be detected
>
> 		  http://archives.postgresql.org/pgsql-patches/2006-04/msg00087.php

>
> * Fix CREATE CAST on DOMAINs
>
>   http://archives.postgresql.org/pgsql-hackers/2006-05/msg00072.php

Backpatch documentation addition to 8.1.X.

> 		  http://archives.postgresql.org/pgsql-bugs/2006-04/msg00248.php

DROP ... IF EXISTS for the following cases:
  language, tablespace, trigger, rule, opclass, function, aggregate. operator, and cast.

>   http://archives.postgresql.org/pgsql-general/2005-08/msg01432.php

>   http://archives.postgresql.org/pgsql-hackers/2006-03/msg00586.php

> * Consider shrinking expired tuples to just their headers
>   http://archives.postgresql.org/pgsql-patches/2006-03/msg00142.php

by creating a reference-count mechanism, similar to what we did a long time
ago for catcache entries.  The back branches have an ugly solution involving
lots of extra copies, but this way is more efficient.  Reference counting is
only applied to tupdescs that are actually in caches --- there seems no need
to use it for tupdescs that are generated in the executor, since they'll go
away during plan shutdown by virtue of being in the per-query memory context.
Neil Conway and Tom Lane

* Auto-fill the free space map by scanning the buffer cache or by
  checking pages written by the background writer

>
>   http://archives.postgresql.org/pgsql-hackers/2006-02/msg01125.php
>