Commit Graph

21505 Commits

Author SHA1 Message Date
Tom Lane f52c5d6749 Forbid marking an identity column as nullable.
GENERATED ALWAYS AS IDENTITY implies NOT NULL, but the code failed
to complain if you overrode that with "GENERATED ALWAYS AS IDENTITY
NULL".  One might think the old behavior was a feature, but it was
inconsistent because the outcome varied depending on the order of
the clauses, so it seems to have been just an oversight.

Per bug #16913 from Pavel Boev.  Back-patch to v10 where identity
columns were introduced.

Vik Fearing (minor tweaks by me)

Discussion: https://postgr.es/m/16913-3b5198410f67d8c6@postgresql.org
2021-03-12 11:08:42 -05:00
Thomas Munro 1b88b8908e Specialize checkpointer sort functions.
When sorting a potentially large number of dirty buffers, the
checkpointer can benefit from a faster sort routine.  One reported
improvement on a large buffer pool system was 1.4s -> 0.6s.

Reviewed-by: Andres Freund <andres@anarazel.de>
Discussion: https://postgr.es/m/CA%2BhUKGJ2-eaDqAum5bxhpMNhvuJmRDZxB_Tow0n-gse%2BHG0Yig%40mail.gmail.com
2021-03-12 23:56:02 +13:00
Amit Kapila 519e4c9ee2 Fix size overflow in calculation introduced by commits d6ad34f3 and bea449c6.
Reported-by: Thomas Munro
Author: Takayuki Tsunakawa
Reviewed-by: Kyotaro Horiguchi
Discussion: https://postgr.es/m/CA+hUKG+oPoFizjABt=GXZWTEHx3oev5rAe2scjW2r6F1rguo5w@mail.gmail.com
2021-03-12 15:42:08 +05:30
Amit Kapila e2cda3c20a Fix use of relcache TriggerDesc field introduced by commit 05c8482f7f.
The commit added code which used a relcache TriggerDesc field across
another cache access, which it shouldn't because the relcache doesn't
guarantee it won't get moved.

Diagnosed-by: Tom Lane
Author: Greg Nancarrow
Reviewed-by: Hou Zhijie, Amit Kapila
Discussion: https://postgr.es/m/2309260.1615485644@sss.pgh.pa.us
2021-03-12 15:14:41 +05:30
Thomas Munro 57dcc2ef33 Poll postmaster less frequently in recovery.
Since commits 9f095299 and f98b8476 we don't poll the postmaster
pipe at all during crash recovery on Linux and FreeBSD, but on other
operating systems we were still doing it for every WAL record.  Do it
less frequently on operating systems where system calls are required, at
the cost of delaying exit a bit after postmaster death.  This avoids
expensive system calls reported to slow down CPU-bound recovery by as
much as 10-30%.

Reviewed-by: Heikki Linnakangas <hlinnaka@iki.fi>
Reviewed-by: Fujii Masao <masao.fujii@oss.nttdata.com>
Reviewed-by: Michael Paquier <michael@paquier.xyz>
Discussion: https://postgr.es/m/CA%2BhUKGK1607VmtrDUHQXrsooU%3Dap4g4R2yaoByWOOA3m8xevUQ%40mail.gmail.com
Discussion: https://postgr.es/m/7261eb39-0369-f2f4-1bb5-62f3b6083b5e@iki.fi
2021-03-12 19:45:42 +13:00
Thomas Munro de829ddf23 Add condition variable for walreceiver shutdown.
Use this new CV to wait for walreceiver shutdown without a sleep/poll
loop, while also benefiting from standard postmaster death handling.

Discussion: https://postgr.es/m/CA%2BhUKGK1607VmtrDUHQXrsooU%3Dap4g4R2yaoByWOOA3m8xevUQ%40mail.gmail.com
2021-03-12 19:45:42 +13:00
Thomas Munro 600f2f50b7 Add condition variable for recovery resume.
Replace a sleep loop with a CV, to get a fast reaction time when
recovery is resumed or the postmaster exits via standard infrastructure.
Unfortunately we still need to wake up every second to perform extra
polling during the recovery pause loop.

Discussion: https://postgr.es/m/CA%2BhUKGK1607VmtrDUHQXrsooU%3Dap4g4R2yaoByWOOA3m8xevUQ%40mail.gmail.com
2021-03-12 19:45:42 +13:00
Fujii Masao b82640df00 Send statistics collected during shutdown checkpoint to the stats collector.
When shutdown is requested, checkpointer performs checkpoint or
restartpoint, and updates the statistics, before it exits. But previously
checkpointer didn't send those statistics to the stats collector.

Shutdown checkpoint and restartpoint are treated as requested ones
instead of scheduled ones, so the number of them are counted in
pg_stat_bgwriter.checkpoints_req column.

Author: Masahiro Ikeda
Reviewed-by: Fujii Masao
Discussion: https://postgr.es/m/0509ad67b585a5b86a83d445dfa75392@oss.nttdata.com
2021-03-12 14:23:00 +09:00
Fujii Masao 33394ee6f2 Force to send remaining WAL stats to the stats collector at walwriter exit.
In walwriter's main loop, WAL stats message is only sent if enough time
has passed since last one was sent to reach PGSTAT_STAT_INTERVAL msecs.
This is necessary to avoid overloading to the stats collector. But this
can cause recent WAL stats to be unsent when walwriter exits.

To ensure that all the WAL stats are sent, this commit makes walwriter
force to send remaining WAL stats to the collector when it exits because
of shutdown request. Note that those remaining WAL stats can still be
unsent when walwriter exits with non-zero exit code (e.g., FATAL error).
This is OK because that walwriter exit leads to server crash and
subsequent recovery discards all the stats. So there is no need to send
remaining stats in that case.

Author: Masahiro Ikeda
Reviewed-by: Fujii Masao
Discussion: https://postgr.es/m/0509ad67b585a5b86a83d445dfa75392@oss.nttdata.com
2021-03-12 13:29:59 +09:00
Thomas Munro 43c6662496 Minor modernization for README.barrier.
Itanium is very uncommon and being discontinued.  ARM is everywhere.
Prefer ARM as an example of an architecture with weak memory ordering.
2021-03-12 15:36:16 +13:00
Peter Geoghegan 7bb97211a5 Save a few cycles during nbtree VACUUM.
Avoid calling RelationGetNumberOfBlocks() unnecessarily in the common
case where there are no deleted but not yet recycled pages to recycle
during a cleanup-only nbtree VACUUM operation.

Follow-up to commit e5d8a999, which (among other things) taught the
"skip full scan" nbtree VACUUM mechanism to only trigger a full index
scan when the absolute number of deleted pages in the index is
considered excessive.
2021-03-11 14:18:23 -08:00
Peter Geoghegan effdd3f3b6 Add back vacuum_cleanup_index_scale_factor parameter.
Commit 9f3665fb removed the vacuum_cleanup_index_scale_factor storage
parameter.  However, that creates dump/reload hazards when moving across
major versions.

Add back the vacuum_cleanup_index_scale_factor parameter (though not the
GUC of the same name) purely to avoid problems when using tools like
pg_upgrade.  The parameter remains disabled and undocumented.

No backpatch to Postgres 13, since vacuum_cleanup_index_scale_factor was
only disabled by REL_13_STABLE's version of master branch commit
9f3665fb in the first place -- the parameter already looks like this on
REL_13_STABLE.

Discussion: https://postgr.es/m/YEm/a3Ko3nKnBuVq@paquier.xyz
2021-03-11 12:42:46 -08:00
Robert Haas 32fd2b57d7 Be clear about whether a recovery pause has taken effect.
Previously, the code and documentation seem to have essentially
assumed than a call to pg_wal_replay_pause() would take place
immediately, but that's not the case, because we only check for a
pause in certain places. This means that a tool that uses this
function and then wants to do something else afterward that is
dependent on the pause having taken effect doesn't know how long it
needs to wait to be sure that no more WAL is going to be replayed.

To avoid that, add a new function pg_get_wal_replay_pause_state()
which returns either 'not paused', 'paused requested', or 'paused'.
After calling pg_wal_replay_pause() the status will immediate change
from 'not paused' to 'pause requested'; when the startup process
has noticed this, the status will change to 'pause'.  For backward
compatibility, pg_is_wal_replay_paused() still exists and returns
the same thing as before: true if a pause has been requested,
whether or not it has taken effect yet; and false if not.
The documentation is updated to clarify.

To improve the changes that a pause request is quickly confirmed
effective, adjust things so that WaitForWALToBecomeAvailable will
swiftly reach a call to recoveryPausesHere() when a pause request
is made.

Dilip Kumar, reviewed by Simon Riggs, Kyotaro Horiguchi, Yugo Nagata,
Masahiko Sawada, and Bharath Rupireddy.

Discussion: http://postgr.es/m/CAFiTN-vcLLWEm8Zr%3DYK83rgYrT9pbC8VJCfa1kY9vL3AUPfu6g%40mail.gmail.com
2021-03-11 15:07:03 -05:00
Peter Geoghegan 5f8727f5a6 VACUUM ANALYZE: Always update pg_class.reltuples.
vacuumlazy.c sometimes fails to update pg_class entries for each index
(to ensure that pg_class.reltuples is current), even though analyze.c
assumed that that must have happened during VACUUM ANALYZE.  There are
at least a couple of reasons for this.  For example, vacuumlazy.c could
fail to update pg_class when the index AM indicated that its statistics
are merely an estimate, per the contract for amvacuumcleanup() routines
established by commit e57345975c back in 2006.

Stop assuming that pg_class must have been updated with accurate
statistics within VACUUM ANALYZE -- update pg_class for indexes at the
same time as the table relation in all cases.  That way VACUUM ANALYZE
will never fail to keep pg_class.reltuples reasonably accurate.

The only downside of this approach (compared to the old approach) is
that it might inaccurately set pg_class.reltuples for indexes whose heap
relation ends up with the same inaccurate value anyway.  This doesn't
seem too bad.  We already consistently called vac_update_relstats() (to
update pg_class) for the heap/table relation twice during any VACUUM
ANALYZE -- once in vacuumlazy.c, and once in analyze.c.  We now make
sure that we call vac_update_relstats() at least once (though often
twice) for each index.

This is follow up work to commit 9f3665fb, which dealt with issues in
btvacuumcleanup().  Technically this fixes an unrelated issue, though.
btvacuumcleanup() no longer provides an accurate num_index_tuples value
following commit 9f3665fb (when there was no btbulkdelete() call during
the VACUUM operation in question), but hashvacuumcleanup() has worked in
the same way for many years now.

Author: Peter Geoghegan <pg@bowt.ie>
Reviewed-By: Masahiko Sawada <sawada.mshk@gmail.com>
Discussion: https://postgr.es/m/CAH2-WzknxdComjhqo4SUxVFk_Q1171GJO2ZgHZ1Y6pion6u8rA@mail.gmail.com
Backpatch: 13-, just like commit 9f3665fb.
2021-03-10 17:07:57 -08:00
Peter Geoghegan 9f3665fbfc Don't consider newly inserted tuples in nbtree VACUUM.
Remove the entire idea of "stale stats" within nbtree VACUUM (stop
caring about stats involving the number of inserted tuples).  Also
remove the vacuum_cleanup_index_scale_factor GUC/param on the master
branch (though just disable them on postgres 13).

The vacuum_cleanup_index_scale_factor/stats interface made the nbtree AM
partially responsible for deciding when pg_class.reltuples stats needed
to be updated.  This seems contrary to the spirit of the index AM API,
though -- it is not actually necessary for an index AM's bulk delete and
cleanup callbacks to provide accurate stats when it happens to be
inconvenient.  The core code owns that.  (Index AMs have the authority
to perform or not perform certain kinds of deferred cleanup based on
their own considerations, such as page deletion and recycling, but that
has little to do with pg_class.reltuples/num_index_tuples.)

This issue was fairly harmless until the introduction of the
autovacuum_vacuum_insert_threshold feature by commit b07642db, which had
an undesirable interaction with the vacuum_cleanup_index_scale_factor
mechanism: it made insert-driven autovacuums perform full index scans,
even though there is no real benefit to doing so.  This has been tied to
a regression with an append-only insert benchmark [1].

Also have remaining cases that perform a full scan of an index during a
cleanup-only nbtree VACUUM indicate that the final tuple count is only
an estimate.  This prevents vacuumlazy.c from setting the index's
pg_class.reltuples in those cases (it will now only update pg_class when
vacuumlazy.c had TIDs for nbtree to bulk delete).  This arguably fixes
an oversight in deduplication-related bugfix commit 48e12913.

[1] https://smalldatum.blogspot.com/2021/01/insert-benchmark-postgres-is-still.html

Author: Peter Geoghegan <pg@bowt.ie>
Reviewed-By: Masahiko Sawada <sawada.mshk@gmail.com>
Discussion: https://postgr.es/m/CAD21AoA4WHthN5uU6+WScZ7+J_RcEjmcuH94qcoUPuB42ShXzg@mail.gmail.com
Backpatch: 13-, where autovacuum_vacuum_insert_threshold was added.
2021-03-10 16:27:01 -08:00
Bruce Momjian 845ac7f847 C comments: improve description of GiST NSN and GistBuildLSN
GiST indexes are complex, so adding more details in the code might help
someone.

Discussion: https://postgr.es/m/20210302164021.GA364@momjian.us
2021-03-10 17:03:10 -05:00
Thomas Munro d87251048a Replace buffer I/O locks with condition variables.
1.  Backends waiting for buffer I/O are now interruptible.

2.  If something goes wrong in a backend that is currently performing
I/O, waiting backends no longer wake up until that backend reaches
AbortBufferIO() and broadcasts on the CV.  Previously, any waiters would
wake up (because the I/O lock was automatically released) and then
busy-loop until AbortBufferIO() cleared BM_IO_IN_PROGRESS.

3.  LWLockMinimallyPadded is removed, as it would now be unused.

Author: Robert Haas <robertmhaas@gmail.com>
Reviewed-by: Thomas Munro <thomas.munro@gmail.com>
Reviewed-by: Julien Rouhaud <rjuju123@gmail.com>
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> (earlier version, 2016)
Discussion: https://postgr.es/m/CA%2BhUKGJ8nBFrjLuCTuqKN0pd2PQOwj9b_jnsiGFFMDvUxahj_A%40mail.gmail.com
Discussion: https://postgr.es/m/CA+Tgmoaj2aPti0yho7FeEf2qt-JgQPRWb0gci_o1Hfr=C56Xng@mail.gmail.com
2021-03-11 10:36:17 +13:00
Tom Lane c3ffe34863 Avoid creating duplicate cached plans for inherited FK constraints.
When a foreign key constraint is applied to a partitioned table, each
leaf partition inherits a similar FK constraint.  We were processing all
of those constraints independently, meaning that in large partitioning
trees we'd build up large collections of cached FK-checking query plans.
However, in all cases but one, the generated queries are actually
identical for all members of the inheritance tree (because, in most
cases, the query only mentions the topmost table of the other side of
the FK relationship).  So we can share a single cached plan among all
the partitions, saving memory, not to mention time to build and maintain
the cached plans.

Keisuke Kuroda and Amit Langote

Discussion: https://postgr.es/m/cab4b85d-9292-967d-adf2-be0d803c3e23@nttcom.co.jp_1
2021-03-10 14:22:31 -05:00
Peter Eisentraut bbaf315309 Add bound check before bsearch() for performance
In the current lazy vacuum implementation, some index AMs such as
btree indexes call lazy_tid_reaped() for each index tuple during
ambulkdelete to check if the index tuple points to the (collected)
garbage tuple.  In that function, we simply call bsearch(), but we
should be able to know the result without bsearch() if the index tuple
points to the heap tuple that is out of range of the collected garbage
tuples.  Therefore, add a simple bound check before resorting to
bsearch().  Testing has shown that this can give significant
performance benefits.

Author: Masahiko Sawada <masahiko.sawada@2ndquadrant.com>
Discussion: https://www.postgresql.org/message-id/flat/CA+fd4k76j8jKzJzcx8UqEugvayaMSnQz0iLUt_XgBp-_-bd22A@mail.gmail.com
2021-03-10 15:19:37 +01:00
Peter Eisentraut 1657b37d7c Small debug message tweak
This makes the wording of the delete case match the update case.
2021-03-10 08:16:38 +01:00
Amit Kapila e4e87a32cc Fix valgrind issue in commit 05c8482f7f.
Initialize other newly added variables in max_parallel_hazard_context via
is_parallel_safe() because we don't check the parallel-safety of target
relations in that function.

Reported-by: Tom Lane as per buildfarm
Author: Amit Kapila
Discussion: https://postgr.es/m/2060179.1615347455@sss.pgh.pa.us
2021-03-10 10:06:39 +05:30
Amit Kapila 05c8482f7f Enable parallel SELECT for "INSERT INTO ... SELECT ...".
Parallel SELECT can't be utilized for INSERT in the following cases:
- INSERT statement uses the ON CONFLICT DO UPDATE clause
- Target table has a parallel-unsafe: trigger, index expression or
  predicate, column default expression or check constraint
- Target table has a parallel-unsafe domain constraint on any column
- Target table is a partitioned table with a parallel-unsafe partition key
  expression or support function

The planner is updated to perform additional parallel-safety checks for
the cases listed above, for determining whether it is safe to run INSERT
in parallel-mode with an underlying parallel SELECT. The planner will
consider using parallel SELECT for "INSERT INTO ... SELECT ...", provided
nothing unsafe is found from the additional parallel-safety checks, or
from the existing parallel-safety checks for SELECT.

While checking parallel-safety, we need to check it for all the partitions
on the table which can be costly especially when we decide not to use a
parallel plan. So, in a separate patch, we will introduce a GUC and or a
reloption to enable/disable parallelism for Insert statements.

Prior to entering parallel-mode for the execution of INSERT with parallel
SELECT, a TransactionId is acquired and assigned to the current
transaction state. This is necessary to prevent the INSERT from attempting
to assign the TransactionId whilst in parallel-mode, which is not allowed.
This approach has a disadvantage in that if the underlying SELECT does not
return any rows, then the TransactionId is not used, however that
shouldn't happen in practice in many cases.

Author: Greg Nancarrow, Amit Langote, Amit Kapila
Reviewed-by: Amit Langote, Hou Zhijie, Takayuki Tsunakawa, Antonin Houska, Bharath Rupireddy, Dilip Kumar, Vignesh C, Zhihong Yu, Amit Kapila
Tested-by: Tang, Haiying
Discussion: https://postgr.es/m/CAJcOf-cXnB5cnMKqWEp2E2z7Mvcd04iLVmV=qpFJrR3AcrTS3g@mail.gmail.com
Discussion: https://postgr.es/m/CAJcOf-fAdj=nDKMsRhQzndm-O13NY4dL6xGcEvdX5Xvbbi0V7g@mail.gmail.com
2021-03-10 07:38:58 +05:30
Fujii Masao ff99918c62 Track total amounts of times spent writing and syncing WAL data to disk.
This commit adds new GUC track_wal_io_timing. When this is enabled,
the total amounts of time XLogWrite writes and issue_xlog_fsync syncs
WAL data to disk are counted in pg_stat_wal. This information would be
useful to check how much WAL write and sync affect the performance.

Enabling track_wal_io_timing will make the server query the operating
system for the current time every time WAL is written or synced,
which may cause significant overhead on some platforms. To avoid such
additional overhead in the server with track_io_timing enabled,
this commit introduces track_wal_io_timing as a separate parameter from
track_io_timing.

Note that WAL write and sync activity by walreceiver has not been tracked yet.

This commit makes the server also track the numbers of times XLogWrite
writes and issue_xlog_fsync syncs WAL data to disk, in pg_stat_wal,
regardless of the setting of track_wal_io_timing. This counters can be
used to calculate the WAL write and sync time per request, for example.

Bump PGSTAT_FILE_FORMAT_ID.

Bump catalog version.

Author: Masahiro Ikeda
Reviewed-By: Japin Li, Hayato Kuroda, Masahiko Sawada, David Johnston, Fujii Masao
Discussion: https://postgr.es/m/0509ad67b585a5b86a83d445dfa75392@oss.nttdata.com
2021-03-09 16:52:06 +09:00
Michael Paquier 9d2d457009 Add support for more progress reporting in COPY
The command (TO or FROM), its type (file, pipe, program or callback),
and the number of tuples excluded by a WHERE clause in COPY FROM are
added to the progress reporting already available.

The column "lines_processed" is renamed to "tuples_processed" to
disambiguate the meaning of this column in the cases of CSV and BINARY
COPY and to be more consistent with the other catalog progress views.

Bump catalog version, again.

Author: Matthias van de Meent
Reviewed-by: Michael Paquier, Justin Pryzby, Bharath Rupireddy, Josef
Šimánek, Tomas Vondra
Discussion: https://postgr.es/m/CAEze2WiOcgdH4aQA8NtZq-4dgvnJzp8PohdeKchPkhMY-jWZXA@mail.gmail.com
2021-03-09 14:21:03 +09:00
Michael Paquier f9264d1524 Remove support for SSL compression
PostgreSQL disabled compression as of e3bdb2d and the documentation
recommends against using it since.  Additionally, SSL compression has
been disabled in OpenSSL since version 1.1.0, and was disabled in many
distributions long before that.  The most recent TLS version, TLSv1.3,
disallows compression at the protocol level.

This commit removes the feature itself, removing support for the libpq
parameter sslcompression (parameter still listed for compatibility
reasons with existing connection strings, just ignored), and removes
the equivalent field in pg_stat_ssl and de facto PgBackendSSLStatus.

Note that, on top of removing the ability to activate compression by
configuration, compression is actively disabled in both frontend and
backend to avoid overrides from local configurations.

A TAP test is added for deprecated SSL parameters to check after
backwards compatibility.

Bump catalog version.

Author: Daniel Gustafsson
Reviewed-by: Peter Eisentraut, Magnus Hagander, Michael Paquier
Discussion:  https://postgr.es/m/7E384D48-11C5-441B-9EC3-F7DB1F8518F6@yesql.se
2021-03-09 11:16:47 +09:00
Tom Lane d4545dc19b Complain if a function-in-FROM returns a set when it shouldn't.
Throw a "function protocol violation" error if a function in FROM
tries to return a set though it wasn't marked proretset.  Although
such cases work at the moment, it doesn't seem like something we
want to guarantee will keep working.  Besides, there are other
negative consequences of not setting the proretset flag, such as
potentially bad plans.

No back-patch, since if there is any third-party code violating
this expectation, people wouldn't appreciate us breaking it in
a minor release.

Discussion: https://postgr.es/m/1636062.1615141782@sss.pgh.pa.us
2021-03-08 18:54:55 -05:00
Tom Lane 5c06abb9b9 Validate the OID argument of pg_import_system_collations().
"SELECT pg_import_system_collations(0)" caused an assertion failure.
With a random nonzero argument --- or indeed with zero, in non-assert
builds --- it would happily make pg_collation entries with garbage
values of collnamespace.  These are harmless as far as I can tell
(unless maybe the OID happens to become used for a schema, later on?).
In any case this isn't a security issue, since the function is
superuser-only.  But it seems like a gotcha for unwary DBAs, so let's
add a check that the given OID belongs to some schema.

Back-patch to v10 where this function was introduced.
2021-03-08 18:21:51 -05:00
Tom Lane 6c20bdb2a2 Further tweak memory management for regex DFAs.
Coverity is still unhappy after commit 190c79884, and after looking
closer I think it might be onto something.  The callers of newdfa()
typically drop out if v->err has been set nonzero, which newdfa()
is faithfully doing if it fails.  However, what if v->err was already
nonzero before we entered newdfa()?  Then newdfa() could succeed and
the caller would promptly leak its result.

I don't think this scenario can actually happen, but the predicate
"v->err is always zero when newdfa() is called" seems difficult to be
entirely sure of; there's a good deal of code that potentially could
get that wrong.

It seems better to adjust the callers to directly check for a null
result instead of relying on ISERR() tests.  This is slightly cheaper
than the previous coding anyway.

Lacking evidence that there's any real bug, no back-patch.
2021-03-08 16:32:29 -05:00
Amit Kapila 8a812e5106 Track replication origin progress for rollbacks.
Commit 1eb6d6527a allowed to track replica origin replay progress for 2PC
but it was not complete. It misses to properly track the progress for
rollback prepared especially it missed updating the code for recovery.
Additionally, we need to allow tracking it on subscriber nodes where
wal_level might not be logical.

It is required to track decoding of 2PC which is committed in PG14
(a271a1b50e) and also nobody complained about this till now so not
backpatching it.

Author: Amit Kapila
Reviewed-by: Michael Paquier and Ajin Cherian
Discussion: https://postgr.es/m/CAA4eK1L-kHmMnSdrRW6UhRbCjR7cgh04c+6psY15qzT6ktcd+g@mail.gmail.com
2021-03-08 07:54:03 +05:30
Heikki Linnakangas 3174d69fb9 Remove server and libpq support for old FE/BE protocol version 2.
Protocol version 3 was introduced in PostgreSQL 7.4. There shouldn't be
many clients or servers left out there without version 3 support. But as
a courtesy, I kept just enough of the old protocol support that we can
still send the "unsupported protocol version" error in v2 format, so that
old clients can display the message properly. Likewise, libpq still
understands v2 ErrorResponse messages when establishing a connection.

The impetus to do this now is that I'm working on a patch to COPY
FROM, to always prefetch some data. We cannot do that safely with the
old protocol, because it requires parsing the input one byte at a time
to detect the end-of-copy marker.

Reviewed-by: Tom Lane, Alvaro Herrera, John Naylor
Discussion: https://www.postgresql.org/message-id/9ec25819-0a8a-d51a-17dc-4150bb3cca3b%40iki.fi
2021-03-04 10:45:55 +02:00
Tom Lane 0a687c8f10 Add trim_array() function.
This has been in the SQL spec since 2008.  It's a pretty thin
wrapper around the array slice functionality, but the spec
says we should have it, so here it is.

Vik Fearing, reviewed by Dian Fay

Discussion: https://postgr.es/m/fc92ce17-9655-8ff1-c62a-4dc4c8ccd815@postgresfriends.org
2021-03-03 16:39:57 -05:00
Peter Eisentraut e527a99055 Some copy-editing of GUC descriptions 2021-03-03 07:14:35 +01:00
Thomas Munro 8eda3eba30 Use sort_template.h for qsort_tuple() and qsort_ssup().
Replace the Perl code previously used to generate specialized sort
functions with sort_template.h.

Reviewed-by: Daniel Gustafsson <daniel@yesql.se>
Discussion: https://postgr.es/m/CA%2BhUKGJ2-eaDqAum5bxhpMNhvuJmRDZxB_Tow0n-gse%2BHG0Yig%40mail.gmail.com
2021-03-03 17:02:32 +13:00
Amit Kapila 19890a064e Add option to enable two_phase commits via pg_create_logical_replication_slot.
Commit 0aa8a01d04 extends the output plugin API to allow decoding of
prepared xacts and allowed the user to enable/disable the two-phase option
via pg_logical_slot_get_changes(). This can lead to a problem such that
the first time when it gets changes via pg_logical_slot_get_changes()
without two_phase option enabled it will not get the prepared even though
prepare is after consistent snapshot. Now next time during getting changes,
if the two_phase option is enabled it can skip prepare because by that
time start decoding point has been moved. So the user will only get commit
prepared.

Allow to enable/disable this option at the create slot time and default
will be false. It will break the existing slots which is fine in a major
release.

Author: Ajin Cherian
Reviewed-by: Amit Kapila and Vignesh C
Discussion: https://postgr.es/m/d0f60d60-133d-bf8d-bd70-47784d8fabf3@enterprisedb.com
2021-03-03 07:34:11 +05:30
Peter Geoghegan 5b2f2af3d9 nbtree page deletion: Add leaftopparent assertion.
Add documenting assertion.  This makes it easier to follow how we
maintain the top parent link in target subtree's half-dead/leaf level
page.
2021-03-02 14:06:07 -08:00
Peter Geoghegan 3d8d5787a3 Fix nbtree page deletion error messages.
Adjust some "can't happen" error messages that assumed that the page
deletion target page must be a half-dead page.  This assumption was
wrong in the case of an internal target page.  Simply refer to these
pages as the target page instead.

Internal pages are never marked half-dead.  There is exactly one
half-dead page for each subtree undergoing deletion.  The half-dead page
is also the target subtree's leaf-level page.  This has been the case
since commit efada2b8, which totally overhauled nbtree page deletion.
2021-03-02 13:02:24 -08:00
Tom Lane d16f8c8e41 Mark default_transaction_read_only as GUC_REPORT.
This allows clients to find out the setting at connection time without
having to expend a query round trip to do so; which is helpful when
trying to identify read/write servers.  (One must also look at
in_hot_standby, but that's already GUC_REPORT, cf bf8a662c9.)
Modifying libpq to make use of this will come soon, but I felt it
cleaner to push the server change separately.

Haribabu Kommi, Greg Nancarrow, Vignesh C; reviewed at various times
by Laurenz Albe, Takayuki Tsunakawa, Peter Smith.

Discussion: https://postgr.es/m/CAF3+xM+8-ztOkaV9gHiJ3wfgENTq97QcjXQt+rbFQ6F7oNzt9A@mail.gmail.com
2021-03-02 13:53:54 -05:00
Tom Lane 4604f83fdf Suppress unnecessary regex subre nodes in a couple more cases.
This extends the changes made in commit cebc1d34e, teaching
parseqatom() to generate fewer or cheaper subre nodes in some edge
cases.  The case of interest here is a quantified atom that is "messy"
only because it has greediness opposite to what preceded it (whereas
captures and backrefs are intrinsically messy).  In this case we don't
need an iteration node, since we don't care where the sub-matches of
the quantifier are; and we might also not need a second concatenation
node.  This seems of only marginal real-world use according to my
testing, but I wanted to get it in before wrapping up this series of
regex performance fixes.

Discussion: https://postgr.es/m/1340281.1613018383@sss.pgh.pa.us
2021-03-02 12:14:14 -05:00
Tom Lane 0c3405cf11 Improve performance of regular expression back-references.
In some cases, at the time that we're doing an NFA-based precheck
of whether a backref subexpression can match at a particular place
in the string, we already know which substring the referenced
subexpression matched.  If so, we might as well forget about the NFA
and just compare the substring; this is faster and it gives an exact
rather than approximate answer.

In general, this optimization can help while we are prechecking within
the second child expression of a concat node, while the capture was
within the first child expression; then the substring was saved during
cdissect() of the first child and will be available to NFA checks done
while cdissect() recurses into the second child.  It can help quite a
lot if the tree looks like

              concat
             /      \
      capture        concat
                    /      \
     expensive stuff        backref

as we will be able to avoid recursively dissecting the "expensive
stuff" before discovering that the backref isn't satisfied with a
particular midpoint that the lower concat node is testing.  This
doesn't help if the concat tree is left-deep, as the capture node
won't get set soon enough (and it's hard to fix that without changing
the engine's match behavior).  Fortunately, right-deep concat trees
are the common case.

Patch by me, reviewed by Joel Jacobson

Discussion: https://postgr.es/m/661609.1614560029@sss.pgh.pa.us
2021-03-02 11:55:12 -05:00
Tom Lane 4aea704a5b Fix semantics of regular expression back-references.
POSIX defines the behavior of back-references thus:

    The back-reference expression '\n' shall match the same (possibly
    empty) string of characters as was matched by a subexpression
    enclosed between "\(" and "\)" preceding the '\n'.

As far as I can see, the back-reference is supposed to consider only
the data characters matched by the referenced subexpression.  However,
because our engine copies the NFA constructed from the referenced
subexpression, it effectively enforces any constraints therein, too.
As an example, '(^.)\1' ought to match 'xx', or any other string
starting with two occurrences of the same character; but in our code
it does not, and indeed can't match anything, because the '^' anchor
constraint is included in the backref's copied NFA.  If POSIX intended
that, you'd think they'd mention it.  Perl for one doesn't act that
way, so it's hard to conclude that this isn't a bug.

Fix by modifying the backref's NFA immediately after it's copied from
the reference, replacing all constraint arcs by EMPTY arcs so that the
constraints are treated as automatically satisfied.  This still allows
us to enforce matching rules that depend only on the data characters;
for example, in '(^\d+).*\1' the NFA matching step will still know
that the backref can only match strings of digits.

Perhaps surprisingly, this change does not affect the results of any
of a rather large corpus of real-world regexes.  Nonetheless, I would
not consider back-patching it, since it's a clear compatibility break.

Patch by me, reviewed by Joel Jacobson

Discussion: https://postgr.es/m/661609.1614560029@sss.pgh.pa.us
2021-03-02 11:34:53 -05:00
Michael Paquier fabde52fab Simplify code to switch pg_class.relrowsecurity in tablecmds.c
The same code pattern was repeated twice to enable or disable ROW LEVEL
SECURITY with an ALTER TABLE command.  This makes the code slightly
cleaner.

Author: Justin Pryzby
Reviewed-by: Zhihong Yu
Discussion: https://postgr.es/m/20210228211854.GC20769@telsasoft.com
2021-03-02 12:30:21 +09:00
Tom Lane ffd3944ab9 Improve reporting for syntax errors in multi-line JSON data.
Point to the specific line where the error was detected; the
previous code tended to include several preceding lines as well.
Avoid re-scanning the entire input to recompute which line that
was.  Simplify the logic a bit.  Add test cases.

Simon Riggs and Hamid Akhtar, reviewed by Daniel Gustafsson and myself

Discussion: https://postgr.es/m/CANbhV-EPBnXm3MF_TTWBwwqgn1a1Ghmep9VHfqmNBQ8BT0f+_g@mail.gmail.com
2021-03-01 16:44:17 -05:00
Thomas Munro bd69ddfcdb Remove obsolete comment for WaitForProcSignalBarrier().
Commit 814f1d8b removed the behavior described.

Reported-by: Amit Kapila <amit.kapila16@gmail.com>
2021-03-02 09:30:57 +13:00
Thomas Munro f5a5773a9d Allow condition variables to be used in interrupt code.
Adjust the condition variable sleep loop to work correctly when code
reached by its internal CHECK_FOR_INTERRUPTS() call interacts with
another condition variable.

There are no such cases currently, but a proposed patch would do this.

Discussion: https://postgr.es/m/CA+hUKGLdemy2gBm80kz20GTe6hNVwoErE8KwcJk6-U56oStjtg@mail.gmail.com
2021-03-01 17:24:47 +13:00
Thomas Munro 814f1d8bc3 Use condition variables for ProcSignalBarriers.
Instead of a poll/sleep loop, use a condition variable for precise
wake-up whenever a backend's pss_barrierGeneration advances.

Discussion: https://postgr.es/m/CA+hUKGLdemy2gBm80kz20GTe6hNVwoErE8KwcJk6-U56oStjtg@mail.gmail.com
2021-03-01 17:23:43 +13:00
Amit Kapila 8bdb1332eb Avoid repeated decoding of prepared transactions after a restart.
In commit a271a1b50e, we allowed decoding at prepare time and the prepare
was decoded again if there is a restart after decoding it. It was done
that way because we can't distinguish between the cases where we have not
decoded the prepare because it was prior to consistent snapshot or we have
decoded it earlier but restarted. To distinguish between these two cases,
we have introduced an initial_consistent_point at the slot level which is
an LSN at which we found a consistent point at the time of slot creation.
This is also the point where we have exported a snapshot for the initial
copy. So, prepare transaction prior to this point are sent along with
commit prepared.

This commit bumps SNAPBUILD_VERSION because of change in SnapBuild. It
will break existing slots which is fine in a major release.

Author: Ajin Cherian, based on idea by Andres Freund
Reviewed-by: Amit Kapila and Vignesh C
Discussion: https://postgr.es/m/d0f60d60-133d-bf8d-bd70-47784d8fabf3@enterprisedb.com
2021-03-01 09:11:18 +05:30
Thomas Munro 6230912f23 Use FeBeWaitSet for walsender.c.
This avoids the need to set up and tear down a fresh WaitEventSet every
time we need need to wait.  We have to add an explicit exit on
postmaster exit (FeBeWaitSet isn't set up to do that automatically), so
move the code to do that into a new function to avoid repetition.

Reviewed-by: Kyotaro Horiguchi <horikyota.ntt@gmail.com> (earlier version)
Discussion: https://postgr.es/m/CA%2BhUKGJAC4Oqao%3DqforhNey20J8CiG2R%3DoBPqvfR0vOJrFysGw%40mail.gmail.com
2021-03-01 16:19:38 +13:00
Thomas Munro a042ba2ba7 Introduce symbolic names for FeBeWaitSet positions.
Previously we used 0 and 1 to refer to the socket and latch in far flung
parts of the tree, without any explanation.  Also use PGINVALID_SOCKET
rather than -1 in a couple of places that didn't already do that.

Reviewed-by: Kyotaro Horiguchi <horikyota.ntt@gmail.com>
Discussion: https://postgr.es/m/CA%2BhUKGJAC4Oqao%3DqforhNey20J8CiG2R%3DoBPqvfR0vOJrFysGw%40mail.gmail.com
2021-03-01 16:10:16 +13:00
Amit Kapila b4e3dc7fd4 Update the docs and comments for decoding of prepared xacts.
Commit a271a1b50e introduced decoding at prepare time in ReorderBuffer.
This can lead to deadlock for out-of-core logical replication solutions
that uses this feature to build distributed 2PC in case such transactions
lock [user] catalog tables exclusively. They need to inform users to not
have locks on catalog tables (via explicit LOCK command) in such
transactions.

Reported-by: Andres Freund
Discussion: https://postgr.es/m/20210222222847.tpnb6eg3yiykzpky@alap3.anarazel.de
2021-03-01 08:14:33 +05:30
Thomas Munro 6148656a0b Use EVFILT_SIGNAL for kqueue latches.
Cut down on system calls and other overheads by waiting for SIGURG
explicitly with kqueue instead of using a signal handler and self-pipe.
Affects *BSD and macOS systems.

This leaves only the poll implementation with a signal handler and the
traditional self-pipe trick.

Discussion: https://postgr.es/m/CA+hUKGJjxPDpzBE0a3hyUywBvaZuC89yx3jK9RFZgfv_KHU7gg@mail.gmail.com
2021-03-01 14:20:04 +13:00