smgrreadv() and smgrwritev() and their md.c implementations call
FileReadV() and FileWriteV(). A range of disk blocks beginning at
'blocknum' and extending for 'nblocks' can be scattered to or gathered
from multiple buffers with a single system call. The traditional
smgrread() and smgrwrite() functions are implemented in terms of the new
functions.
Later commits will introduce calls with nblocks > 1, but the following
behavioral changes can be seen already:
* After a short transfer we'll now retry until we eventually read 0
bytes (= EOF) or get ENOSPC, EDQUOT, EFBIG etc, where previously we
would infer the reason. Retrying is consistent with xlog.c's
treatment of large WAL writes, and arguably also xlog.c and fd.c's
treatment of EINTR. Arbitrary short returns for larger transfers have
been observed on several OSes, and might in theory also happen for
transient reasons with our own pg_p*v() fallback code.
* After unexpected EOF or -1, the error thrown now talks about
a range even for the single block case, eg "blocks 42..42".
Reviewed-by: Heikki Linnakangas <hlinnaka@iki.fi>
Discussion: https://postgr.es/m/CA+hUKGJkOiOCa+mag4BF+zHo7qo=o9CFheB8=g6uT5TUm2gkvA@mail.gmail.com
We didn't explain this clearly until somewhere deep in the
"Extending SQL" chapter, but really it ought to be mentioned
in the introductory material too.
Discussion: https://postgr.es/m/4097442.1694967650@sss.pgh.pa.us
Originally, this routine relied on track_io_timing to check if a time
interval for an I/O operation stored in pg_stat_io should be initialized
or not. However, the addition of WAL statistics to pg_stat_io requires
that the initialization happens when track_wal_io_timing is enabled,
which is dependent on the code path where the I/O operation happens.
Author: Nazir Bilal Yavuz
Discussion: https://postgr.es/m/CAN55FZ3AiQ+ZMxUuXnBpd0Rrh1YhwJ5FudkHg=JU0P+-W8T4Vg@mail.gmail.com
During the development that led to commit 357889eb17, for a time we
had the value LIMIT_OPTION_DEFAULT, which was mostly but not completely
removed later on, before commit. Complete the removal now.
Author: Zhang Mingli <avamingli@gmail.com>
Discussion: https://postgr.es/m/59d61a1a-3858-475a-964f-24468c97cc67@Spark
Previously smgrprefetch() could issue POSIX_FADV_WILLNEED advice for a
single block at a time. Add an nblocks argument so that we can do the
same for a range of blocks. This usually produces a single system call,
but might need to loop if it crosses a segment boundary. Initially it
is only called with nblocks == 1, but proposed patches will make wider
calls.
Reviewed-by: Heikki Linnakangas <hlinnaka@iki.fi> (earlier version)
Discussion: https://postgr.es/m/CA+hUKGJkOiOCa+mag4BF+zHo7qo=o9CFheB8=g6uT5TUm2gkvA@mail.gmail.com
In v16 and up (since commit afbfc0298), large object ownership
checking has been broken because object_ownercheck() didn't take care
of the discrepancy between our object-address representation of large
objects (classId == LargeObjectRelationId) and the catalog where their
ownership info is actually stored (LargeObjectMetadataRelationId).
This resulted in failures such as "unrecognized class ID: 2613"
when trying to update blob properties as a non-superuser.
Poking around for related bugs, I found that AlterObjectOwner_internal
would pass the wrong classId to the PostAlterHook in the no-op code
path where the large object already has the desired owner. Also,
recordExtObjInitPriv checked for the wrong classId; that bug is only
latent because the stanza is dead code anyway, but as long as we're
carrying it around it should be less wrong. These bugs are quite old.
In HEAD, we can reduce the scope for future bugs of this ilk by
changing AlterObjectOwner_internal's API to let the translation happen
inside that function, rather than requiring callers to know about it.
A more bulletproof fix, perhaps, would be to start using
LargeObjectMetadataRelationId as the dependency and object-address
classId for blobs. However that has substantial risk of breaking
third-party code; even within our own code, it'd create hassles
for pg_dump which would have to cope with a version-dependent
representation. For now, keep the status quo.
Discussion: https://postgr.es/m/2650449.1702497209@sss.pgh.pa.us
Dead tuples are ignored and are not marked as dead during recovery, as
it can lead to MVCC issues on a standby because its xmin may not match
with the primary. This information is tracked by a field called
"xactStartedInRecovery" in the transaction state data, switched on when
starting a transaction in recovery.
Unfortunately, this information was not correctly tracked when starting
a subtransaction, because the transaction state used for the
subtransaction did not update "xactStartedInRecovery" based on the state
of its parent. This would cause index scans done in subtransactions to
return inconsistent data, depending on how the xmin of the primary
and/or the standby evolved.
This is broken since the introduction of hot standby in efc16ea520, so
backpatch all the way down.
Author: Fei Changhong
Reviewed-by: Kyotaro Horiguchi
Discussion: https://postgr.es/m/tencent_C4D907A5093C071A029712E73B43C6512706@qq.com
Backpatch-through: 12
FileReadV() and FileWriteV() adapt pg_preadv() and pg_pwritev() for
fd.c's virtual file descriptors. The simple FileRead() and FileWrite()
functions are now implemented in terms of the vectored functions, to
avoid code duplication, and they are converted back to the corresponding
simple system calls further down (commit 15c9ac36). Later work will
make more interesting multi-iovec calls.
The traditional behavior of reporting a "fake" ENOSPC error is
simplified. It's now always set for non-failing writes, for the benefit
of callers that expect to log a meaningful "%m" if they determine that
the write was short. (Perhaps we should consider getting rid of that
expectation one day.)
Reviewed-by: Heikki Linnakangas <hlinnaka@iki.fi>
Discussion: https://postgr.es/m/CA+hUKGJkOiOCa+mag4BF+zHo7qo=o9CFheB8=g6uT5TUm2gkvA@mail.gmail.com
compute_remaining_iovec() is a re-usable routine for retrying after
pg_readv() or pg_writev() reports a short transfer. This will gain new
users in a later commit, but can already replace the open-coded
equivalent code in the existing pg_pwritev_with_retry() function.
Reviewed-by: Heikki Linnakangas <hlinnaka@iki.fi>
Discussion: https://postgr.es/m/CA+hUKGJkOiOCa+mag4BF+zHo7qo=o9CFheB8=g6uT5TUm2gkvA@mail.gmail.com
These two macros wouldn't work if used in an inline function definition
in a header seen by g++, because __builtin_types_compatible_p is only
available in C. Redirect to standard C++ const_cast (which also
adds/removes volatile despite its name).
Per cpluspluscheck failure in a development branch.
Suggested-by: Peter Eisentraut <peter@eisentraut.org>
Discussion: https://postgr.es/m/CA%2BhUKGK3OXFjkOyZiw-DgL2bUqk9by1uGuCnViJX786W%2BfyDSw%40mail.gmail.com
OpenSSL will sometimes return SSL_ERROR_SYSCALL without having set
errno; this is apparently a reflection of recv(2)'s habit of not
setting errno when reporting EOF. Ensure that we treat such cases
the same as read EOF. Previously, we'd frequently report them like
"could not accept SSL connection: Success" which is confusing, or
worse report them with an unrelated errno left over from some
previous syscall.
To fix, ensure that errno is zeroed immediately before the call,
and report its value only when it's not zero afterwards; otherwise
report EOF.
For consistency, I've applied the same coding pattern in libpq's
pqsecure_raw_read(). Bare recv(2) shouldn't really return -1 without
setting errno, but in case it does we might as well cope.
Per report from Andres Freund. Back-patch to all supported versions.
Discussion: https://postgr.es/m/20231208181451.deqnflwxqoehhxpe@awork3.anarazel.de
This removes the production json_encoding_clause_opt, instead merging
it into json_format_clause. Also remove the auxiliary
makeJsonEncoding() function.
Reviewed-by: Amit Langote <amitlangote09@gmail.com>
Discussion: https://postgr.es/m/202312071841.u2gueb5dsrbk%40alvherre.pgsql
This GUC was intended as a debugging help in the 9.0 area when hot
standby and streaming replication were being developped, able to offer
more information at LOG level rather than DEBUGn. There are more tools
available these days that are able to offer rather equivalent
information, like pg_waldump introduced in 9.3. It is not obvious how
this facility is useful these days, so let's remove it.
Author: Bharath Rupireddy
Discussion: https://postgr.es/m/ZXEXEAUVFrvpquSd@paquier.xyz
The apply worker needs to update the state of the subscription tables to
'READY' during the synchronization phase which requires locking the
corresponding subscription. The apply worker also waits for the
subscription tables to reach the 'SYNCDONE' state after holding the locks
on the subscription and the wait is done using WaitLatch. The 'SYNCDONE'
state is changed by tablesync workers again by locking the corresponding
subscription. Both the state updates use AccessShareLock mode to lock the
subscription, so they can't block each other. However, a backend can
simultaneously try to acquire a lock on the same subscription using
AccessExclusiveLock mode to alter the subscription. Now, the backend's
wait on a lock can sneak in between the apply worker and table sync worker
causing deadlock.
In other words, apply_worker waits for tablesync worker which waits for
backend, and backend waits for apply worker. This is not detected by the
deadlock detector because apply worker uses WaitLatch.
The fix is to release existing locks in apply worker before it starts to
wait for tablesync worker to change the state.
Reported-by: Tomas Vondra
Author: Shlok Kyal
Reviewed-by: Amit Kapila, Peter Smith
Backpatch-through: 12
Discussion: https://postgr.es/m/d291bb50-12c4-e8af-2af2-7bb9bb4d8e3e@enterprisedb.com
Remove comments that supposed that holding a pin was a useful interlock
for _bt_walk_left(). There are times when _bt_walk_left() doesn't hold
either a lock or a pin on any page, so clearly this can't be true.
_bt_walk_left() is even prepared to deal with concurrent deletion of
both the original page and any pages to its left.
Oversight in commit 2ed5b87f96.
This commit does the following:
* In datum_to_json_internal(), the call to IsValidJsonNumber() is
replaced with simplified validation code. This avoids an extra
call to strlen() in this path, and it avoids validating the
entire string (which is okay since we know we're dealing with a
numeric data type's output).
* In datum_to_json_internal(), the call to escape_json() in the
JSONTYPE_NUMERIC path is replaced with code that just surrounds
the string with quotes. In passing, some other nearby calls to
appendStringInfo() have been replaced with similar code to avoid
unnecessary calls to vsnprintf().
* In composite_to_json(), the length of the separator is now
determined at compile time to avoid unnecessary calls to
strlen().
On my machine, this speeds up a benchmark for the proposed COPY TO
(FORMAT json) command with many integers by upwards of 20%. There
are likely other code paths that could be given a similar
treatment, but that is left as a future exercise.
Reviewed-by: Jeff Davis, Tom Lane, David Rowley, John Naylor
Discussion: https://postgr.es/m/20231207231251.GB3359478%40nathanxps13
Teach _bt_binsrch (and related helper routines like _bt_search and
_bt_compare) about the initial positioning requirements of backward
scans. Routines like _bt_binsrch already know all about "nextkey"
searches, so it seems natural to teach them about "goback"/backward
searches, too. These concepts are closely related, and are much easier
to understand when discussed together.
Now that certain implementation details are hidden from _bt_first, it's
straightforward to add a new optimization: backward scans using the <
strategy now avoid extra leaf page accesses in certain "boundary cases".
Consider the following example, which uses the tenk1 table (and its
tenk1_hundred index) from the standard regression tests:
SELECT * FROM tenk1 WHERE hundred < 12 ORDER BY hundred DESC LIMIT 1;
Before this commit, nbtree would scan two leaf pages, even though it was
only really necessary to scan one leaf page. We'll now descend straight
to the leaf page containing a (12, -inf) high key instead. The scan
will locate matching non-pivot tuples with "hundred" values starting
from the value 11. The scan won't waste a page access on the right
sibling leaf page, which cannot possibly contain any matching tuples.
You can think of the optimization added by this commit as disabling an
optimization (the _bt_compare "!pivotsearch" behavior that was added to
Postgres 12 in commit dd299df8) for a small subset of cases where it was
always counterproductive.
Equivalently, you can think of the new optimization as extending the
"pivotsearch" behavior that page deletion by VACUUM has long required
(since the aforementioned Postgres 12 commit went in) to other, similar
cases. Obviously, this isn't strictly necessary for these new cases
(unlike VACUUM, _bt_first is prepared to move the scan to the left once
on the leaf level), but the underlying principle is the same.
Author: Peter Geoghegan <pg@bowt.ie>
Reviewed-By: Matthias van de Meent <boekewurm+postgres@gmail.com>
Discussion: https://postgr.es/m/CAH2-Wz=XPzM8HzaLPq278Vms420mVSHfgs9wi5tjFKHcapZCEw@mail.gmail.com
Allow using multiple worker processes to build BRIN index, which until
now was supported only for BTREE indexes. For large tables this often
results in significant speedup when the build is CPU-bound.
The work is split in a simple way - each worker builds BRIN summaries on
a subset of the table, determined by the regular parallel scan used to
read the data, and feeds them into a shared tuplesort which sorts them
by blkno (start of the range). The leader then reads this sorted stream
of ranges, merges duplicates (which may happen if the parallel scan does
not align with BRIN pages_per_range), and adds the resulting ranges into
the index.
The number of duplicate results produced by workers (requiring merging
in the leader process) should be fairly small, thanks to how parallel
scans assign chunks to workers. The likelihood of duplicate results may
increase for higher pages_per_range values, but then there are fewer
page ranges in total. In any case, we expect the merging to be much
cheaper than summarization, so this should be a win.
Most of the parallelism infrastructure is a simplified copy of the code
used by BTREE indexes, omitting the parts irrelevant for BRIN indexes
(e.g. uniqueness checks).
This also introduces a new index AM flag amcanbuildparallel, determining
whether to attempt to start parallel workers for the index build.
Original patch by me, with reviews and substantial reworks by Matthias
van de Meent, certainly enough to make him a co-author.
Author: Tomas Vondra, Matthias van de Meent
Reviewed-by: Matthias van de Meent
Discussion: https://postgr.es/m/c2ee7d69-ce17-43f2-d1a0-9811edbda6e6%40enterprisedb.com
When building BRIN indexes, the brinbuildCallback only advances to the
next page range when seeing a tuple that doesn't belong to the current
one. This means that the index may end up missing ranges at the end of
the table, if those pages do not contain any indexable tuples.
We tend not to have completely empty pages at the end of a relation, but
this also applies to partial indexes, where the tuples may simply not
match the index predicate. This results in inefficient scans using the
affected BRIN index - without the summaries, the page ranges have to be
read and processed, which consumes I/O and possibly also CPU time.
The existing code already added empty ranges for earlier parts of the
table, this commit makes sure we add them for the ranges at the end of
the table too.
Patch by Matthias van de Meent, with review/improvements by me.
Author: Matthias van de Meent
Reviewed-by: Tomas Vondra
Discussion: https://postgr.es/m/CAEze2WiMsPZg%3DxkvSF_jt4%3D69k6K7gz5B8V2wY3gCGZ%2B1BzCbQ%40mail.gmail.com
Commit 252dcb3239 introduced initdb template caching to speed up
tests by re-using initdb output. The initdb command didn't however
use the --no-clean option to preserve generated data in case initdb
crashes unlike pg_regress which does do this. This adds the option
to initdb to aid debugging.
While changing the commandline, switch to using long options for
initdb to make the code more self-documenting.
Author: Matthias van de Meent <boekewurm+postgres@gmail.com>
Discussion: https://postgr.es/m/CAEze2WhSTjfK_M+Ea4GSQp8odrEOaQS8HyORd1TJUEiyXaB+rw@mail.gmail.com
This works today, and it's valuable to ensure it doesn't get broken
if/when we get around to refactoring the implementation.
Author: Nikolay Shaplov <dhyan@nataraj.su>
Discussion: https://postgr.es/m/4563991.km65PDbjlG@thinkpad-pgpro
While checking if a record could fit in the circular WAL decoding
buffer, the coding from commit 3f1ce973 used arithmetic that could
overflow. 64 bit systems were unaffected for various technical reasons,
which probably explains the lack of problem reports. Likewise for 32
bit systems running known 32 bit kernels. The systems at risk of
problems appear to be 32 bit processes running on 64 bit kernels, with
unlucky placement in memory.
Per complaint from GCC -fsanitize=undefined -m32, while testing
variations of 039_end_of_wal.pl.
Back-patch to 15.
Reviewed-by: Nathan Bossart <nathandbossart@gmail.com>
Reviewed-by: Robert Haas <robertmhaas@gmail.com>
Discussion: https://postgr.es/m/CA%2BhUKGKH0oRPOX7DhiQ_b51sM8HqcPp2J3WA-Oen%3DdXog%2BAGGQ%40mail.gmail.com
During a pg_upgrade test using an old dump, all references to the old
regress shared library path (so, dylib or dll) are updated to point to
the library path used by the new build, to ensure a consistent
comparison between the old and new dumps.
The test previously relied on a hardcoded value of "src/test/regress/"
to build the new path value, which would point to an incorrect location
for the meson and vpath builds. This is replaced by REGRESS_SHLIB, able
to point to the correct location of the regress shared library.
Author: Alexander Lakhin
Discussion: https://postgr.es/m/a628d8ad-a08a-2eab-4ca9-641bc82d3193@gmail.com
Backpatch-through: 15
tts_virtual_copyslot() contained an Assert that checked that the srcslot
contained <= attributes than the dstslot. This seems to be backwards as
if the srcslot contained fewer attributes then the dstslot could be left
with stale Datum values from the previously stored tuple. It might make
more sense to allow the source to contain additional attributes and only
copy the leading ones that also exist in the destination, however, that's
not what we're doing here.
Here we just remove the Assert from tts_virtual_copyslot() and add an
Assert to ExecCopySlot() to verify the attribute counts match. There
does not seem to be any places where the destination contains fewer
attributes, so instead of going to the trouble of making the code
properly handle this, let's just ensure the attribute counts match. If
this Assert fails then that will indicate that we do have cases that
require us to handle the srcslot with more attributes than the dstslot.
It seems better to only write this code if there's a genuine requirement
for it rather than write it now only to leave it untested.
Thanks to Andres Freund for helping with the analysis of this.
Discussion: https://postgr.es/m/CAApHDvpMAvBL0T+TRORquyx1iqFQKMVTXtqNocOw0Pa2uh1heg@mail.gmail.com
An invalid index is skipped when doing REINDEX CONCURRENTLY at table
level, with INDEX_CORRUPTED used as errcode. This is confusing,
because an invalid index could exist after an interruption. The errcode
is switched to OBJECT_NOT_IN_PREREQUISITE_STATE instead, as per a
suggestion from Andres Freund.
While on it, the error messages are reworded, and a hint is added,
telling how to rebuild an invalid index in this case. This has been
suggested by Noah Misch.
Discussion: https://postgr.es/m/20231118230958.4fm3fhk4ypshxopa@awork3.anarazel.de
The commit 29d0a77fa6 labelled binary_upgrade_logical_slot_has_caught_up()
as a non-strict function to allow providing a better error message to callers
in case the passed slot_name is NULL. On further discussion, it seems that
it is not helpful to have a different error message for NULL input in this
function, so this patch marks the function as strict.
This patch also removes the explicit permission check to use replication
slots as this function is invoked only by superusers and instead adds an
Assert.
Reported-by: Masahiko Sawada
Author: Hayato Kuroda
Reviewed-by: Vignesh C
Discussion: https://postgr.es/m/CAD21AoDSyiBKkMXBxN_gUayZZUCOgyHnG8Ge8rcPXNP3Tf6B4g@mail.gmail.com
A REINDEX CONCURRENTLY run on a table with no indexes would always pop
the topmost snapshot from the active snapshot stack, making the snapshot
handling inconsistent between the multiple-relation and single-relation
cases. This commit slightly changes the snapshot stack handling so as a
snapshot is popped only ReindexMultipleInternal() in this case after a
relation has been reindexed, fixing a problem where an event trigger
function may need a snapshot but does not have one. This also keeps the
places where PopActiveSnapshot() is called closer to each other.
While on it, this expands the existing tests to cover all the cases that
could be faced with REINDEX commands and such event triggers, for one or
more relations, with or without indexes.
This behavior is inconsistent since 5dc92b844e, but we've never had a
need for an active snapshot at the end of a REINDEX until now.
Thanks also to Jian He for the input.
Reported-by: Alexander Lakhin
Discussion: https://postgr.es/m/cb538743-484c-eb6a-a8c5-359980cd3a17@gmail.com
pg_test_fsync's signal_cleanup() intentionally ignores the write()
result since there's not much we could do about it, but certain
compilers make that harder than it ought to be.
This was missed in commit 52e98d4502.
Reviewed-by: Tristan Partin, Peter Eisentraut
Discussion: https://postgr.es/m/20231206161839.GA2828158%40nathanxps13
This commit removes the restriction that would not apply filters to the
dumps used for comparison in the TAP test of pg_upgrade when using the
same base version for the old and new nodes.
The previous logic would fail on Windows if loading a dump while using
the same set of binaries for the old and new nodes, as the library
dependencies updated in the old dump would append CRLFs to the dump
file as it is treated as a text file. The dump filtering logic replaces
all CRLFs (\r\n) by LFs (\n), which is able to prevent this issue.
When the old and new versions of the binaries are the same,
AdjustUpgrade removes all blank lines, removes version-based comments
generated by pg_dump and replaces CRLFs by LFs.
Reported-by: Alexander Lakhin
Discussion: https://postgr.es/m/60d434b9-53d9-9ea1-819b-efebdcf44e41@gmail.com
Backpatch-through: 15
SEMI-JOIN is deparsed as the EXISTS subquery. It references outer and inner
relations, so it should be evaluated as the condition in the upper-level WHERE
clause. The signatures of deparseFromExprForRel() and deparseRangeTblRef() are
revised so that they can add conditions to the upper level.
PgFdwRelationInfo now has a hidden_subquery_rels field, referencing the relids
used in the inner parts of semi-join. They can't be referred to from upper
relations and should be used internally for equivalence member searches.
The planner can create semi-join, which refers to inner rel vars in its target
list. However, we deparse semi-join as an exists() subquery. So we skip the
case when the target list references to inner rel of semi-join.
Author: Alexander Pyhalov
Reviewed-by: Ashutosh Bapat, Ian Lawrence Barwick, Yuuki Fujii, Tomas Vondra
Discussion: https://postgr.es/m/c9e2a757cf3ac2333714eaf83a9cc184@postgrespro.ru
The old names were too generic, and would have applied to any binary
that made use of JsonManifestParseContext. Rename to make the names
specific to pg_verifybackup, since there are plans afoot to reuse
this infrastructure.
Per suggestion from Álvaro Herrra.
Discussion: http://postgr.es/m/202311131625.o7hzq3oukuyd@alvherre.pgsql
There is no real reason to just run multiple words together when
we can instead punctuate them with marks intended for that purpose.
Per suggestion from Álvaro Herrera.
Discussion: http://postgr.es/m/202311161021.nisg7imt7kyf@alvherre.pgsql
When preparing commit 98e675ed7a I accidentally forgot to run
pgindent, which did produce a diff. Fix by adding the required
whitespace per the koel buildfarm failure.
Commit 5a991ef869 accidentally reversed the order of the tuples
and fields parameters, making the error message incorrectly refer
to 3 tuples with 1 field when IDENTIFY_SYSTEM returns 1 tuple and
3 or 4 fields. Fix by changing the order of the parameters. This
also adds a comment describing why we check for < 3 when postgres
since 9.4 has been sending 4 fields.
Backpatch all the way since the bug is almost a decade old.
Author: Tomonari Katsumata <t.katsumata1122@gmail.com>
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Bug: #18224
Backpatch-through: v12
Thomas Munro