Original coding would corrupt the hashtable if the item being updated was
at the end of its bucket chain and the new hash key hashed to that same
bucket. Diagnosis and fix by Heikki Linnakangas.
Because the return value of lseek() was assigned to an unsigned size_t
variable, we'd fail to notice an error return code -1. Compiler gave a
warning about this.
Andres Freund
Dates outside the supported range could be entered, but would not print
reasonably, and operations such as conversion to timestamp wouldn't behave
sanely either. Since this has the potential to result in undumpable table
data, it seems worth back-patching.
Hitoshi Harada
This seems to have been invented in 2011 to represent GMT+3, non daylight
savings rules, as now used in Europe/Kaliningrad and Europe/Minsk.
There are no conflicts so might as well add it to the Default list.
Per bug #7804 from Ruslan Izmaylov.
The code in PostPrepare_Locks supposed that it could reassign locks to
the prepared transaction's dummy PGPROC by deleting the PROCLOCK table
entries and immediately creating new ones. This was safe when that code
was written, but since we invented partitioning of the shared lock table,
it's not safe --- another process could steal away the PROCLOCK entry in
the short interval when it's on the freelist. Then, if we were otherwise
out of shared memory, PostPrepare_Locks would have to PANIC, since it's
too late to back out of the PREPARE at that point.
Fix by inventing a dynahash.c function to atomically update a hashtable
entry's key. (This might possibly have other uses in future.)
This is an ancient bug that in principle we ought to back-patch, but the
odds of someone hitting it in the field seem really tiny, because (a) the
risk window is small, and (b) nobody runs servers with maxed-out lock
tables for long, because they'll be getting non-PANIC out-of-memory errors
anyway. So fixing it in HEAD seems sufficient, at least until the new
code has gotten some testing.
In commit 71450d7fd6, we added code to inform
suitably-intelligent compilers that ereport() doesn't return if the elevel
is ERROR or higher. This patch extends that to elog(), and also fixes a
double-evaluation hazard that the previous commit created in ereport(),
as well as reducing the emitted code size.
The elog() improvement requires the compiler to support __VA_ARGS__, which
should be available in just about anything nowadays since it's required by
C99. But our minimum language baseline is still C89, so add a configure
test for that.
The previous commit assumed that ereport's elevel could be evaluated twice,
which isn't terribly safe --- there are already counterexamples in xlog.c.
On compilers that have __builtin_constant_p, we can use that to protect the
second test, since there's no possible optimization gain if the compiler
doesn't know the value of elevel. Otherwise, use a local variable inside
the macros to prevent double evaluation. The local-variable solution is
inferior because (a) it leads to useless code being emitted when elevel
isn't constant, and (b) it increases the optimization level needed for the
compiler to recognize that subsequent code is unreachable. But it seems
better than not teaching non-gcc compilers about unreachability at all.
Lastly, if the compiler has __builtin_unreachable(), we can use that
instead of abort(), resulting in a noticeable code savings since no
function call is actually emitted. However, it seems wise to do this only
in non-assert builds. In an assert build, continue to use abort(), so that
the behavior will be predictable and debuggable if the "impossible"
happens.
These changes involve making the ereport and elog macros emit do-while
statement blocks not just expressions, which forces small changes in
a few call sites.
Andres Freund, Tom Lane, Heikki Linnakangas
This is now used by ecpg tests, and not clobbered by pg_upgrade
tests. This change won't affect anything that doesn't set this
environment variable, but will enable the buildfarm to control
exactly what port regression test installs will be running on,
and thus to detect possible rogue postmasters more easily.
Backpatch to release 9.2 where EXTRA_REGRESS_OPTS was first used.
Historically we've used a couple of very ad-hoc fudge factors to try to
get the right results when indexes of different sizes would satisfy a
query with the same number of index leaf tuples being visited. In
commit 21a39de580 I tweaked one of these
fudge factors, with results that proved disastrous for larger indexes.
Commit bf01e34b55 fudged it some more,
but still with not a lot of principle behind it.
What seems like a better way to address these issues is to explicitly model
index-descent costs, since that's what's really at stake when considering
diferent indexes with similar leaf-page-level costs. We tried that once
long ago, and found that charging random_page_cost per page descended
through was way too much, because upper btree levels tend to stay in cache
in real-world workloads. However, there's still CPU costs to think about,
and the previous fudge factors can be seen as a crude attempt to account
for those costs. So this patch replaces those fudge factors with explicit
charges for the number of tuple comparisons needed to descend the index
tree, plus a small charge per page touched in the descent. The cost
multipliers are chosen so that the resulting charges are in the vicinity of
the historical (pre-9.2) fudge factors for indexes of up to about a million
tuples, while not ballooning unreasonably beyond that, as the old fudge
factor did (even more so in 9.2).
To make this work accurately for btree indexes, add some code that allows
extraction of the known root-page height from a btree. There's no
equivalent number readily available for other index types, but we can use
the log of the number of index pages as an approximate substitute.
This seems like too much of a behavioral change to risk back-patching,
but it should improve matters going forward. In 9.2 I'll just revert
the fudge-factor change.
This means we can now construct a configure test for the library
presence. Previously these parameters were only figured out at
build time in plperl's GnuMakefile.
If VirtualXactLock() has to wait for a transaction that holds its VXID lock
as a fast-path lock, it must first convert the fast-path lock to a regular
lock. It failed to take the required "partition" lock on the main
shared-memory lock table while doing so. This is the direct cause of the
assert failure in GetLockStatusData() recently observed in the buildfarm,
but more worryingly it could result in arbitrary corruption of the shared
lock table if some other process were concurrently engaged in modifying the
same partition of the lock table. Fortunately, VirtualXactLock() is only
used by CREATE INDEX CONCURRENTLY and DROP INDEX CONCURRENTLY, so the
opportunities for failure are fewer than they might have been.
In passing, improve some comments and be a bit more consistent about
order of operations.
Adds commandline option -R to pg_basebackup that creates a recovery.conf which
enables standby mode using the same parameters that pg_basebackup used to
connect to the master, and writes it into the output directory (or injects it
in the tar file when tar format is used).
Zoltan Boszormenyi, modified by Magnus Hagander, reviewed by Amit Kapila & Fujii Masao
The PL/Python build on OS X was previously hardcoded to use the system
installation of Python, ignoring whatever was specified to configure.
Except that it would use the header files from configure, which could
lead to mismatches. It was not possible to build against a custom
Python installation.
Now, we check in configure how the specified Python installation was
built and use that, supporting framework and non-framework builds.
This reverts commit be0dfbad36.
The previous information that Py_RETURN_TRUE and Py_RETURN_FALSE are
supported in Python 2.3 is wrong. They require Python 2.4. Update the
comment about that.
SPI_execute() and related functions create a CachedPlan, execute it once,
and immediately discard it, so that the functionality offered by
plancache.c is of no value in this code path. And performance measurements
show that the extra data copying and invalidation checking done by
plancache.c slows down simple queries by 10% or more compared to 9.1.
However, enough of the SPI code is shared with functions that do need plan
caching that it seems impractical to bypass plancache.c altogether.
Instead, let's invent a variant version of cached plans that preserves
99% of the API but doesn't offer any of the actual functionality, nor the
overhead. This puts SPI_execute() performance back on par, or maybe even
slightly better, than it was before. This change should resolve recent
complaints of performance degradation from Dong Ye, Pavel Stehule, and
others.
By avoiding data copying, this change also reduces the amount of memory
needed to execute many-statement SPI_execute() strings, as for instance in
a recent complaint from Tomas Vondra.
An additional benefit of this change is that multi-statement SPI_execute()
query strings are now processed fully serially, that is we complete
execution of earlier statements before running parse analysis and planning
on following ones. This eliminates a long-standing POLA violation, in that
DDL that affects the behavior of a later statement will now behave as
expected.
Back-patch to 9.2, since this was a performance regression compared to 9.1.
(In 9.2, place the added struct fields so as to avoid changing the offsets
of existing fields.)
Heikki Linnakangas and Tom Lane
If you take a base backup from a standby server with "pg_basebackup -X
fetch", and the timeline switches while the backup is being taken, the
backup used to fail with an error "requested WAL segment %s has already
been removed". This is because the server-side code that sends over the
required WAL files would not construct the WAL filename with the correct
timeline after a switch.
Fix that by using readdir() to scan pg_xlog for all the WAL segments in the
range, regardless of timeline.
Also, include all timeline history files in the backup, if taken with
"-X fetch". That fixes another related bug: If a timeline switch happened
just before the backup was initiated in a standby, the WAL segment
containing the initial checkpoint record contains WAL from the older
timeline too. Recovery will not accept that without a timeline history file
that lists the older timeline.
Backpatch to 9.2. Versions prior to that were not affected as you could not
take a base backup from a standby before 9.2.
Streaming replication can fetch any missing timeline history files from the
master, but recovery would read the timeline history file for the target
timeline before reading the checkpoint record, and before walreceiver has
had a chance to fetch it from the master. Delay reading it, and the sanity
checks involving timeline history, until after reading the checkpoint
record.
There is at least one scenario where this makes a difference: if you take
a base backup from a standby server right after a timeline switch, the
WAL segment containing the initial checkpoint record will begin with an
older timeline ID. Without the timeline history file, recovering that file
will fail as the older timeline ID is not recognized to be an ancestor of
the target timeline. If you try to recover from such a backup, using only
streaming replication to fetch the WAL, this patch is required for that to
work.
... not on auxiliary processes. I managed to overlook the fact that I
had disabled assertions on my HEAD checkout long ago.
Hopefully this will turn the buildfarm green again, and put an end to
today's silliness.
This makes it possible to include them only where they are used, so
we can avoid the conflict of the uid_t and gid_t datatypes that happened
in plperl (since plperl doesn't need the tar functions)
Commit da07a1e8 was broken for EXEC_BACKEND because I failed to realize
that the MaxBackends recomputation needed to be duplicated by
subprocesses in SubPostmasterMain. However, instead of having the value
be recomputed at all, it's better to assign the correct value at
postmaster initialization time, and have it be propagated to exec'ed
backends via BackendParameters.
MaxBackends stays as zero until after modules in
shared_preload_libraries have had a chance to register bgworkers, since
the value is going to be untrustworthy till that's finished.
Heikki Linnakangas and Álvaro Herrera
After receiving some WAL over streaming replication, try to open the file
from the timeline we're currently recieving, not recoveryTargetTLI. They
are usually the same, which is why wasn't noticed before, but you'd get
an error if there have been more than one timeline switch between the
current point in WAL and the recovery target.
Move some of the tar functionality that existed mostly duplicated
in both pg_dump and the walsender basebackup functionality into
port/tar.c instead, so it can be used from both. It will also be
used by pg_basebackup in the future, which would've caused a third
copy of it around.
Zoltan Boszormenyi and Magnus Hagander
In commit 11e131854f, we improved the
rule/view dumping code so that it would produce valid query representations
even if some of the tables involved in a query had been renamed since the
query was parsed. This patch extends that idea to fix problems that occur
when individual columns are renamed, or added or dropped. As before, the
core of the fix is to assign unique new aliases when a name conflict has
been created. This is complicated by the JOIN USING feature, which
requires the same column alias to be used in both input relations, but we
can handle that with a sufficiently complex approach to assigning aliases.
A fortiori, this patch takes care of situations where the query didn't have
unique column names to begin with, such as in a recent complaint from Bryan
Nuse. (Because of expansion of "SELECT *", re-parsing a dumped query can
require column name uniqueness even though the original text did not.)
The cascading standby patch in 9.2 changed the way WAL files are treated
when restored from the archive. Before, they were restored under a temporary
filename, and not kept in pg_xlog, but after the patch, they were copied
under pg_xlog. This is necessary for a cascading standby to find them, but
it also means that if the archive goes offline and a standby is restarted,
it can recover back to where it was using the files in pg_xlog. It also
means that if you take an offline backup from a standby server, it includes
all the required WAL files in pg_xlog.
However, the same change was not made to timeline history files, so if the
WAL segment containing the checkpoint record contains a timeline switch, you
will still get an error if you try to restart recovery without the archive,
or recover from an offline backup taken from the standby.
With this patch, timeline history files restored from archive are copied
into pg_xlog like WAL files are, so that pg_xlog contains all the files
required to recover. This is a corner-case pre-existing issue in 9.2, but
even more important in master where it's possible for a standby to follow a
timeline switch through streaming replication. To make that possible, the
timeline history files must be present in pg_xlog.
This is again intended to support extensions to the event trigger
functionality. This may go a bit further than we need for that
purpose, but there's some value in being consistent, and the OID
may be useful for other purposes also.
Dimitri Fontaine
This gets rid of XLByteLT, XLByteLE, XLByteEQ and XLByteAdvance.
These were useful for brevity when XLogRecPtrs were split in
xlogid/xrecoff; but now that they are simple uint64's, they are just
clutter. The only downside to making this change would be ease of
backporting patches, but that has been negated by other substantive
changes to the involved code anyway. The clarity of simpler expressions
makes the change worthwhile.
Most of the changes are mechanical, but in a couple of places, the patch
author chose to invert the operator sense, making the code flow more
logical (and more in line with preceding comments).
Author: Andres Freund
Eyeballed by Dimitri Fontaine and Alvaro Herrera
Code review for commit 2f582f76b1945929ff07116cd4639747ce9bb8a1: don't use
a static variable for what ought to be a deparse_context field, fix
non-multibyte-safe test for spaces, avoid useless and potentially O(N^2)
(though admittedly with a very small constant) calculations of wrap
positions when we aren't going to wrap.
Ensure comments accurately reflect state of code
given new understanding, and recent changes.
Include example code from Noah Misch to
illustrate how rd_newRelfilenodeSubid can be
reset deterministically. No code changes.
Teach RelationCacheInvalidate() to keep rd_newRelfilenodeSubid across rel cache
message overflows, so that behaviour is now fully deterministic.
Noah Misch
Heikki Linnakangas
Tom Lane
Alvaro Herrera
Peter Eisentraut
Andrew Dunstan
Magnus Hagander
Robert Haas
Bruce Momjian
Simon Riggs