enlarge the memory chunk in-place when it was feasible to do so. This turns
out to not work well at all for scenarios involving repeated cycles of
palloc/repalloc/pfree: the eventually freed chunks go into the wrong freelist
for the next initial palloc request, and so we consume memory indefinitely.
While that could be defended against, the number of cases where the
optimization can still be applied drops significantly, and adjusting the
initial sizes of StringInfo buffers makes it drop to almost nothing.
Seems better to just remove the extra complexity.
Per recent discussion and testing.
likewise increase the initial size of the scanner's literal buffer to 1024
(from 128). Instrumentation of the regression tests suggests that this
saves a useful amount of repalloc() traffic --- the number of calls occurring
during one set of tests drops from about 6900 to about 3900. The old sizes
were chosen in the late 90's with an eye to machines much smaller than
are common today.
regexp_split_to_table() within a single query. This is only a partial
solution, as it turns out that with enough matches per string these
functions can also tickle a repalloc() misbehavior. But fixing that
is a topic for a separate patch.
that cached compiled patterns will still be there when the function is next
called. Clean up looping logic, thereby fixing bug identified by Pavel
Stehule. Share setup code between the two functions, add some comments, and
avoid risky mixing of int and size_t variables. Clean up the documentation a
tad, and accept all the flag characters mentioned in table 9-19 rather than
just a subset.
constant flow of new connection requests could prevent the postmaster from
completing a shutdown or crash restart. This is done by labeling child
processes that are "dead ends", that is, we know that they were launched only
to tell a client that it can't connect. These processes are managed
separately so that they don't confuse us into thinking that we can't advance
to the next stage of a shutdown or restart sequence, until the very end
where we must wait for them to drain out so we can delete the shmem segment.
Per discussion of a misbehavior reported by Keaton Adams.
Since this code was baroque already, and my first attempt at fixing the
problem made it entirely impenetrable, I took the opportunity to rewrite it
in a state-machine style. That eliminates some duplicated code sections and
hopefully makes everything a bit clearer.
hash table is allocated in a child context of the agg node's memory
context, MemoryContextReset() will reset but *not* delete the child
context. Since ExecReScanAgg() proceeds to build a new hash table
from scratch (in a new sub-context), this results in leaking the
header for the previous memory context. Therefore, use
MemoryContextResetAndDeleteChildren() instead.
Credit: My colleague Sailesh Krishnamurthy at Truviso for isolating
the cause of the leak.
child memory contexts is indented two spaces to the right of its
parent context. This should make it easier to deduce the memory
context hierarchy from the output of MemoryContextStats().
between the setting of log_line_prefix and the setting of log_timezone. We
can't realistically set log_timezone any earlier than we do now, so the best
behavior seems to be to use GMT zone if any timestamps are to be logged during
early startup. Create a dummy zone variable with a minimal definition of GMT
(in particular it will never know about leap seconds), so that we can set it
up without reference to any external files.
as well as regular backends: if no regular backend launches before the autovac
launcher tries to start an autovac worker, the postmaster would get an Assert
fault due to calling PostmasterRandom before random_seed was initialized.
Cleanest solution seems to be to take the initialization of random_seed out
of ServerLoop and let PostmasterRandom do it for itself.
displayed in the postmaster log. This avoids Windows-specific problems with
localized time zone names that are in the wrong encoding, and generally seems
like a good idea to forestall other potential platform-dependent issues.
To preserve the existing behavior that all backends will log in the same time
zone, create a new GUC variable log_timezone that can only be changed on a
system-wide basis, and reference log-related calculations to that zone instead
of the TimeZone variable.
This fixes the issue reported by Hiroshi Saito that timestamps printed by
xlog.c startup could be improperly localized on Windows. We still need a
simpler patch for that problem in the back branches, however.
not bothering to initialize is_autovacuum for regular backends, meaning there
was a significant chance of the postmaster prematurely sending them SIGTERM
during database shutdown. Also, leaving the cancel key unset for an autovac
worker meant that any client could send it SIGINT, which doesn't sound
especially good either.
so that we will be able to create a cookie for all processes for CSVlogs.
It is set wherever MyProcPid is set. Take the opportunity to remove the now
unnecessary session-only restriction on the %s and %c escapes in log_line_prefix.
before reporting a transaction committed. Data consistency is still
guaranteed (unlike setting fsync = off), but a crash may lose the effects
of the last few transactions. Patch by Simon, some editorialization by Tom.
clauses in which one side or the other references both sides of the join
cannot be removed as redundant, because that expression won't have been
constrained below the join. Per report from Sergey Burladyan.
CVS HEAD does not contain this bug due to EquivalenceClass rewrite, but it
seems wise to include the regression test for it anyway.
with the recent patch to log temp file sizes at removal time. Doesn't seem
worth fixing since it's unused.
In passing, make a few elog messages conform to the message style guide.
named pg_toast_temp_nnn, alongside the pg_temp_nnn schemas used for the temp
tables themselves. This allows low-level code such as the relcache to
recognize that these tables are indeed temporary, which enables various
optimizations such as not WAL-logging changes and using local rather than
shared buffers for access. Aside from obvious performance benefits, this
provides a solution to bug #3483, in which other backends unexpectedly held
open file references to temporary tables. The scheme preserves the property
that TOAST tables are not in any schema that's normally in the search path,
so they don't conflict with user table names.
initdb forced because of changes in system view definitions.
sugar for PL/PgSQL set-returning functions that want to return the result
of evaluating a query; it should also be more efficient than repeated
RETURN NEXT statements. Based on an earlier patch from Pavel Stehule.
checking whether an IS NULL/IS NOT NULL clause is implied or refuted by
a strict function. Per example from Dawid Kuroczko.
Backpatch to 8.2 since this is arguably a performance bug.
and fsync WAL at convenient intervals. For the moment it just tries to
offload this work from backends, but soon it will be responsible for
guaranteeing a maximum delay before asynchronously-committed transactions
will be flushed to disk.
This is a portion of Simon Riggs' async-commit patch, committed to CVS
separately because a background WAL writer seems like it might be a good idea
independently of the async-commit feature. I rebased walwriter.c on
bgwriter.c because it seemed like a more appropriate way of handling signals;
while the startup/shutdown logic in postmaster.c is more like autovac because
we want walwriter to quit before we start the shutdown checkpoint.
I/O utilization, per discussion.
While at it, lower the autovacuum vacuum and analyze threshold values to 50
tuples. It is a bit higher (i.e. more conservative) than what I originally
proposed but much better than the old values for small tables.
Tom Lane