child attnums are the same, before it grovels through each and every child
column looking for a name match.  Saves some time in large inheritance trees,
per example from Greg.

values: don't throw away perfectly good hash bits, and increase the shift
distances so as to provide more separation in the common case where some of
the key values are small integers (and so their hashes are too, because
hashfunc.c doesn't try all that hard).  This reduces the runtime of
SearchCatCache by a factor of 4 in an example provided by Greg Stark,
in which the planner spends a whole lot of time searching the two-key
STATRELATT cache.  It seems unlikely to hurt in other cases, but maybe
we could do even better?

when a relation is opened multiple times in the same transaction.  This is
particularly useful for system catalogs, which we may heap_open or index_open
many times in a transaction, and it doesn't really cost anything extra even
if the rel is touched but once.  Motivated by study of an example from Greg
Stark, in which pgstat_initstats() accounted for an unreasonably large
fraction of the runtime.

In very large queries this accounts for a noticeable fraction of
planning time.  Per an example from Greg Stark.

multiple releases.

checklist.

Security: CVE-2007-2138

This is needed to allow a security-definer function to set a truly secure
value of search_path.  Without it, a malicious user can use temporary objects
to execute code with the privileges of the security-definer function.  Even
pushing the temp schema to the back of the search path is not quite good
enough, because a function or operator at the back of the path might still
capture control from one nearer the front due to having a more exact datatype
match.  Hence, disable searching the temp schema altogether for functions and
operators.

Security: CVE-2007-2138

failed (due to lock conflicts or out-of-space).  We might have already
extended the index's filesystem EOF before failing, causing the EOF to be
beyond what the metapage says is the last used page.  Hence the invariant
maintained by the code needs to be "EOF is at or beyond last used page",
not "EOF is exactly the last used page".  Problem was created by my patch
of 2006-11-19 that attempted to repair bug #2737.  Since that was
back-patched to 7.4, this needs to be as well.  Per report and test case
from Vlastimil Krejcir.

pass-by-reference data type and the RETURN statement is within an EXCEPTION
block.  Bug introduced by my fix of 2007-01-28 to use per-subtransaction
ExprContexts/EStates; since that wasn't back-patched into older branches,
only 8.2 and HEAD are affected.  Per report from Gary Winslow.

Riggs, additional code and docs by me.  Per discussion.

win32.mak file.
Enable building with kerberos support using the win32.mak file.

Hiroshi Saito + me

< 		o -Add MOVE
< 		o -Add support for SCROLL cursors
> 		o Add support for MOVE and SCROLL cursors

Make it possible to set the default from builenv.bat.

Per request from Dave Page

Backpatch doc change to 8.2.X.

multi-byte value.  It can also be a single-byte encoded character if
the client and server versions match.

Backpatch to 8.2.X.

< 		o -Add support for WITH HOLD and SCROLL cursors
> 		o -Add support for SCROLL cursors
> 		o Add support for WITH HOLD cursors

< 		o Add support for WITH HOLD and SCROLL cursors
> 		o -Add support for WITH HOLD and SCROLL cursors

< 		o Add MOVE
> 		o -Add MOVE

<   Currently all schemas are owned by the super-user because they are
<   copied from the template1 database.
>   Currently all schemas are owned by the super-user because they are copied
>   from the template1 database.  However, since all objects are inherited
>   from the template database, it is not clear that setting schemas to the db
>   owner is correct.

doing so can result in crash if an sinval reset occurs meanwhile.
I believe this explains intermittent buildfarm failures in cluster test.

< * %Set proper permissions on non-system schemas during db creation
> * Set proper permissions on non-system schemas during db creation

competing alternatives for indexes to use in a bitmap scan.  The former
coding took estimated selectivity as an overriding factor, causing it to
sometimes choose indexes that were much slower to scan than ones with a
slightly worse selectivity.  It was also too narrow-minded about which
combinations of indexes to consider ANDing.  The rewrite makes it pay more
attention to index scan cost than selectivity; this seems sane since it's
impossible to have very bad selectivity with low cost, whereas the reverse
isn't true.  Also, we now consider each index alone, as well as adding
each index to an AND-group led by each prior index, for a total of about
O(N^2) rather than O(N) combinations considered.  This makes the results
much less dependent on the exact order in which the indexes are
considered.  It's still a lot cheaper than an O(2^N) exhaustive search.
A prefilter step eliminates all but the cheapest of those indexes using
the same set of WHERE conditions, to keep the effective value of N down in
scenarios where the DBA has created lots of partially-redundant indexes.

Merlin Moncure

Kris Jurka