The planner can sometimes compute very large values for numGroups, and in
cases where we have no alternative to building a hashtable, such a value
will get fed directly to BuildTupleHashTable as its nbuckets parameter.
There were two ways in which that could go bad. First, BuildTupleHashTable
declared the parameter as "int" but most callers were passing "long"s,
so on 64-bit machines undetected overflow could occur leading to a bogus
negative value. The obvious fix for that is to change the parameter to
"long", which is what I've done in HEAD. In the back branches that seems a
bit risky, though, since third-party code might be calling this function.
So for them, just put in a kluge to treat negative inputs as INT_MAX.
Second, hash_create can go nuts with extremely large requested table sizes
(notably, my_log2 becomes an infinite loop for inputs larger than
LONG_MAX/2). What seems most appropriate to avoid that is to bound the
initial table size request to work_mem.
This fixes bug #6035 reported by Daniel Schreiber. Although the reported
case only occurs back to 8.4 since it involves WITH RECURSIVE, I think
it's a good idea to install the defenses in all supported branches.
Historically we didn't do this, even though we had the information, because
plpgsql passed its Params via SPI APIs that only include type OIDs not
typmods. Now that plpgsql uses parser callbacks to create Params, it's
easy to insert the right typmod. This should generally result in lower
surprise factors, because a plpgsql variable that is declared with a typmod
will now work more like a table column with the same typmod. In particular
it's the "right" way to fix bug #6020, in which plpgsql's attempt to return
an anonymous record type is defeated by stricter record-type matching
checks that were added in 9.0. However, it's not impossible that this
could result in subtle behavioral changes that could break somebody's
existing plpgsql code, so I'm afraid to back-patch this change into
released branches. In those branches we'll have to lobotomize the
record-type checks instead.
avoids the overhead of one function call when calling MemoryContextReset(),
and it seems like the isReset optimization would be applicable to any new
memory context we might invent in the future anyway.
This buys back the overhead I just added in previous patch to always call
MemoryContextReset() in ExecScan, even when there's no quals or projections.
there's no quals or projections. Currently this only matters for foreign
scans, as none of the other scan nodes litter the per-tuple memory context
when there's no quals or projections.
Even though this only affects the insertion of a parenthesized word,
it's unwise to assume that parentheses can pass through untranslated.
And in any case, the new version is clearer in the code and for
translators.
Also, we removed the display of the current value of
max_connections/MaxBackends from some messages earlier, because it was
confusing, so do that in the remaining one as well.
This was broken in commit ef19dc6d39 by
the Bunce/Hunsaker/Dunstan team, which moved the declaration from
plperl_create_sub to plperl_call_perl_trigger_func. This doesn't
actually work because the validator code would not find the variable
declared; and even if you manage to get past the validator, it still
doesn't work because get_sv("_TD", GV_ADD) doesn't have the expected
effect. The only reason this got beyond testing is that it only fails
in strict mode.
We need to declare it as a global just like %_SHARED; it is simpler than
trying to actually do what the patch initially intended, and is said to
have the same performance benefit.
As a more serious issue, fix $_TD not being properly local()ized,
meaning nested trigger functions would clobber $_TD.
Alex Hunsaker, per test report from Greg Mullane
pg_dump has some heuristic rules for whether to dump casts and procedural
languages, since it's not all that easy to distinguish built-in ones from
user-defined ones. However, we should not apply those rules to objects
that belong to an extension, but just use the perfectly well-defined rules
for what to do with extension member objects. Otherwise we might
mistakenly lose extension member objects during a binary upgrade (which is
the only time that we'd want to dump extension members).
This commit fixes psql, pg_dump, and the information schema to be
consistent with the backend changes which I made as part of commit
be90032e0d, and also includes a
related documentation tweak.
Shigeru Hanada, with slight adjustment.
The code to assemble ldap_get_values_len's output into a single string
wrote the terminating null one byte past where it should. Fix that,
and make some other cosmetic adjustments to make the code a trifle more
readable and more in line with usual Postgres coding style.
Also, free the "result" string when done with it, to avoid a permanent
memory leak.
Bug report and patch by Albe Laurenz, cosmetic adjustments by me.
Failure to distinguish these cases is the real cause behind the recent
reports of Windows builds crashing on 'infinity'::timestamp, which was
directly due to failure to establish a value of timezone_abbreviations
in postmaster child processes. The postmaster had the desired value,
but write_one_nondefault_variable() didn't transmit it to backends.
To fix that, invent a new value PGC_S_DYNAMIC_DEFAULT, and be sure to use
that or PGC_S_ENV_VAR (as appropriate) for "default" settings that are
computed during initialization. (We need both because there's at least
one variable that could receive a value from either source.)
This commit also fixes ProcessConfigFile's failure to restore the correct
default value for certain GUC variables if they are set in postgresql.conf
and then removed/commented out of the file. We have to recompute and
reinstall the value for any GUC variable that could have received a value
from PGC_S_DYNAMIC_DEFAULT or PGC_S_ENV_VAR sources, and there were a
number of oversights. (That whole thing is a crock that needs to be
redesigned, but not today.)
However, I intentionally didn't make it work "exactly right" for the cases
of timezone and log_timezone. The exactly right behavior would involve
running select_default_timezone, which we'd have to do independently in
each postgres process, causing the whole database to become entirely
unresponsive for as much as several seconds. That didn't seem like a good
idea, especially since the variable's removal from postgresql.conf might be
just an accidental edit. Instead the behavior is to adopt the previously
active setting as if it were default.
Note that this patch creates an ABI break for extensions that use any of
the PGC_S_XXX constants; they'll need to be recompiled.
Use ColLabel in place of ColId, so that reserved words are accepted as if
they were not reserved. Also, remove BCONST and XCONST, which were never
documented as allowed. Allowing those exposes to users an implementation
detail, namely the format in which the lexer outputs such constants, that
seems unwise to expose.
No documentation change needed, since this just makes the code act more
like you'd expect from reading the CREATE TRIGGER man page.
Per complaint from Szymon Guz and subsequent discussion.
Normally nel == 0 works okay because the initial value of "last" will be
less than "base"; but if "base" is zero then the calculation wraps around
and we have a very large (unsigned) value for "last", so that the loop can
be entered and we get a SIGSEGV on a bogus pointer.
This is certainly the proximate cause of the recent reports of Windows
builds crashing on 'infinity'::timestamp --- evidently, they're either not
setting an active timezonetktbl, or setting an empty one. It's not yet
clear to me why it's only happening on Windows and not happening on any
buildfarm member. But even if that's due to some bug elsewhere, it seems
wise for this function to not choke on the powerup values of
timezonetktbl/sztimezonetktbl.
I also changed the copy of this code in ecpglib, although I am not sure
whether it's exposed to a similar hazard.
Per report and stack trace from Richard Broersma.
The recent cleanup of GUC assign hooks got rid of the kludge of using
"unknown" as a magic value for timezone and log_timezone. But I forgot
to update the documentation to match, as noted by Martin Pitt.
Discard any collation aliases that match the built-in pg_collation entries
(ie, "default", "C", "POSIX"). Such aliases would be refused by a CREATE
COLLATION command, but since initdb is injecting them via a simple INSERT,
it has to make the corresponding check for itself. Per Martin Pitt's
report of funny behavior in a machine that had a bogus "C.UTF-8" locale.
Also, use E'' syntax for the output of escape_quotes, as per its header
comment.
This doesn't work as expected because the isolationtester program requires
libpq to already be installed. While it works when you've already installed
libpq, having to already have done "make install" defeats most of the point
of a check with a temp installation. And there are weird corner cases if
the dynamic linker picks up an old libpq.so from system library directories.
Remove the target (or more precisely, make it print a helpful message) so
people don't expect the case to work.
Remove random system #includes in favor of using postgres_fe.h. (The
alternative to that is letting this module grow its own configuration
testing ability...)
Also fix the "make clean" target to actually clean things up.
Per local testing.
The SSI patch inserted a call of RegisterPredicateLockingXid into
GetNewTransactionId, which was a bad idea on a couple of grounds. First,
it's not necessary to hold XidGenLock while manipulating that shared
memory, and doing so is bad because XidGenLock is a high-contention lock
that should be held for as short a time as possible. (Not to mention that
it adds an entirely unnecessary deadlock hazard, since we must take
SerializableXactHashLock as well.) Second, the specific place where it was
put was between extending CLOG and advancing nextXid, which could result in
unpleasant behavior in case of a failure there. Pull the call out to
AssignTransactionId, which is much safer and arguably better from a
modularity standpoint too.
There is more work to do to clean up the failure-before-advancing-nextXid
issue, but that is a separate change that will need to be back-patched.
So for the moment I just want to make GetNewTransactionId look the same as
it did in prior versions.
These were labeled with precedences just to avoid attaching explicit
precedences to the productions in which they were the last terminal symbol.
Since a terminal symbol precedence marking can affect many other things
too, it seems like better practice to attach precedence labels to the
productions, and not mark the terminal symbols.
Ideally we'd also remove the precedence attached to NULL_P, but it turns
out that we are actually depending on that having a precedence higher than
POSTFIXOP, else we get a shift/reduce conflict for postfix operators in
b_expr. (Which more or less proves my point about these markings having a
high risk of unexpected consequences.) For the moment, move NULL_P into
the set of keywords grouped with IDENT, so that at least it will act
similarly to non-keywords; and document the interaction.
After finding an EXISTS or ANY sub-select that can be converted to a
semi-join or anti-join, we should recurse into the body of the sub-select.
This allows cases such as EXISTS-within-EXISTS to be optimized properly.
The original coding would leave the lower sub-select as a SubLink, which
is no better and often worse than what we can do with a join. Per example
from Wayne Conrad.
Back-patch to 8.4. There is a related issue in older versions' handling
of pull_up_IN_clauses, but they're lame enough anyway about the whole area
that it seems not worth the extra work to try to fix.
The previous coding would allow requests up to half of maxBlockSize to be
treated as "chunks", but when that actually did happen, we'd waste nearly
half of the space in the malloc block containing the chunk, if no smaller
requests came along to fill it. Avoid this scenario by limiting the
maximum size of a chunk to 1/8th maxBlockSize, so that we can waste no more
than 1/8th of the allocated space. This will not change the behavior at
all for the default context size parameters (with large maxBlockSize),
but it will change the behavior when using ALLOCSET_SMALL_MAXSIZE.
In particular, there's no longer a need for spell.c to be overly concerned
about the request size parameters it uses, so remove a rather unhelpful
comment about that.
Merlin Moncure, per an idea of Tom Lane's
install-sh can install multiple files at once, so for loops are not
necessary. This was already changed for the rest of the code some
time ago, but pgxs.mk was apparently forgotten, and the obsolete
coding style has now been copied to the PLs as well.
This also fixes the problem that the for loops in question did not
catch errors.
We must lock out autovacuuming of the old toast table before computing the
OldestXmin horizon we will use. Otherwise, autovacuum could start on the
toast table later, compute a later OldestXmin horizon, and remove as DEAD
toast tuples that we still need (because we think their parent tuples are
only RECENTLY_DEAD). Per further thought about bug #5998.
