(it's so nice to have a buildfarm member that actively rejects naked
uses of strcasecmp). This coding is still pretty awful, though, since
it's going to be O(N^2) in the number of guc variables. May I direct
your attention to bsearch?
are mostly excluded by constraints: do the CE test a bit earlier to save
some adjust_appendrel_attrs() work on excluded children, and arrange to
use array indexing rather than rt_fetch() to fetch RTEs in the main body
of the planner. The latter is something I'd wanted to do for awhile anyway,
but seeing list_nth_cell() as 35% of the runtime gets one's attention.
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.
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.
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.
sequence for dumping without also selecting its owning table. Make it not try
to emit ALTER SEQUENCE OWNED BY in this situation.
Per report from Michael Nolan.
processes to be running simultaneously. Also, now autovacuum processes do not
count towards the max_connections limit; they are counted separately from
regular processes, and are limited by the new GUC variable
autovacuum_max_workers.
The launcher now has intelligence to launch workers on each database every
autovacuum_naptime seconds, limited only on the max amount of worker slots
available.
Also, the global worker I/O utilization is limited by the vacuum cost-based
delay feature. Workers are "balanced" so that the total I/O consumption does
not exceed the established limit. This part of the patch was contributed by
ITAGAKI Takahiro.
Per discussion.
a replan. I had originally thought this was not necessary, but the new
SPI facilities create a path whereby queries planned with non-default
options can get into the cache, so it is necessary.
access to the planner's cursor-related planning options, and provide new
FETCH/MOVE routines that allow access to the full power of those commands.
Small refactoring of planner(), pg_plan_query(), and pg_plan_queries()
APIs to make it convenient to pass the planning options down from SPI.
This is the core-code portion of Pavel Stehule's patch for scrollable
cursor support in plpgsql; I'll review and apply the plpgsql changes
separately.
possibly be any useful pathkeys --- to wit, queries with neither any
join clauses nor any ORDER BY request. It's nearly free to check for
this case and it saves a useful fraction of the planning time for simple
queries.
If this breaks things due to missing libxslt, then I'll have to
revert it, but let's see if it breaks the buildfarm.
Workarounds in case libxslt is missing include:
. don't configure with libxml, or
. don't build contrib modules from the contrib Makefile (use the individual module Makefiles instead), or
. change the xml2 Makefile
fast flow of new fsync requests can prevent mdsync() from ever completing.
This was an unforeseen consequence of a patch added in Mar 2006 to prevent
the fsync request queue from overflowing. Problem identified by Heikki
Linnakangas and independently by ITAGAKI Takahiro; fix based on ideas from
Takahiro-san, Heikki, and Tom.
Back-patch as far as 8.1 because a previous back-patch introduced the problem
into 8.1 ...
