Commit Graph

15252 Commits

Author SHA1 Message Date
Alvaro Herrera
6f5c8a8ec2
Remove bogus restriction from BEFORE UPDATE triggers
In trying to protect the user from inconsistent behavior, commit
487e9861d0 "Enable BEFORE row-level triggers for partitioned tables"
tried to prevent BEFORE UPDATE FOR EACH ROW triggers from moving the row
from one partition to another.  However, it turns out that the
restriction is wrong in two ways: first, it fails spuriously, preventing
valid situations from working, as in bug #16794; and second, they don't
protect from any misbehavior, because tuple routing would cope anyway.

Fix by removing that restriction.

We keep the same restriction on BEFORE INSERT FOR EACH ROW triggers,
though.  It is valid and useful there.  In the future we could remove it
by having tuple reroute work for inserts as it does for updates.

Backpatch to 13.

Author: Álvaro Herrera <alvherre@alvh.no-ip.org>
Reported-by: Phillip Menke <pg@pmenke.de>
Discussion: https://postgr.es/m/16794-350a655580fbb9ae@postgresql.org
2021-01-28 16:56:07 -03:00
Peter Eisentraut
b034ef9b37 Remove gratuitous uses of deprecated SELECT INTO
CREATE TABLE AS has been preferred over SELECT INTO (outside of ecpg
and PL/pgSQL) for a long time.  There were still a few uses of SELECT
INTO in tests and documentation, some old, some more recent.  This
changes them to CREATE TABLE AS.  Some occurrences in the tests remain
where they are specifically testing SELECT INTO parsing or similar.

Discussion: https://www.postgresql.org/message-id/flat/96dc0df3-e13a-a85d-d045-d6e2c85218da%40enterprisedb.com
2021-01-28 14:28:41 +01:00
Peter Geoghegan
e19594c5c0 Reduce the default value of vacuum_cost_page_miss.
When commit f425b605 introduced cost based vacuum delays back in 2004,
the defaults reflected then-current trends in hardware, as well as
certain historical limitations in PostgreSQL.  There have been enormous
improvements in both areas since that time.  The cost limit GUC defaults
finally became much more representative of current trends following
commit cbccac37, which decreased autovacuum_vacuum_cost_delay's default
by 10x for PostgreSQL 12 (it went from 20ms to only 2ms).

The relative costs have shifted too.  This should also be accounted for
by the defaults.  More specifically, the relative importance of avoiding
dirtying pages within VACUUM has greatly increased, primarily due to
main memory capacity scaling and trends in flash storage.  Within
Postgres itself, improvements like sequential access during index
vacuuming (at least in nbtree and GiST indexes) have also been
contributing factors.

To reflect all this, decrease the default of vacuum_cost_page_miss to 2.
Since the default of vacuum_cost_page_dirty remains 20, dirtying a page
is now considered 10x "costlier" than a page miss by default.

Author: Peter Geoghegan <pg@bowt.ie>
Discussion: https://postgr.es/m/CAH2-WzmLPFnkWT8xMjmcsm7YS3+_Qi3iRWAb2+_Bc8UhVyHfuA@mail.gmail.com
2021-01-27 15:11:13 -08:00
Tom Lane
662affcfe9 Doc: improve documentation for UNNEST().
Per a user question, spell out that UNNEST() returns array elements
in storage order; also provide an example to clarify the behavior for
multi-dimensional arrays.

While here, also clarify the SELECT reference page's description of
WITH ORDINALITY.  These details were already given in 7.2.1.4, but
a reference page should not omit details.

Back-patch to v13; there's not room in the table in older versions.

Discussion: https://postgr.es/m/FF1FB31F-0507-4F18-9559-2DE6E07E3B43@gmail.com
2021-01-27 12:50:22 -05:00
Michael Paquier
32bef75829 doc: Remove reference to views for TRUNCATE privilege
The page about privilege rights mentioned that TRUNCATE could be applied
to views or even other relation types.  This is confusing as this
command can be used only on tables and on partitioned tables.

Oversight in afc4a78.

Reported-by: Harisai Hari
Reviewed-by: Laurenz Albe
Discussion: https://postgr.es/m/161157636877.14625.15340884663716426087@wrigleys.postgresql.org
Backpatch-through: 12
2021-01-27 13:40:33 +09:00
Tom Lane
d5a83d79c9 Rethink recently-added SPI interfaces.
SPI_execute_with_receiver and SPI_cursor_parse_open_with_paramlist are
new in v14 (cf. commit 2f48ede08).  Before they can get out the door,
let's change their APIs to follow the practice recently established by
SPI_prepare_extended etc: shove all optional arguments into a struct
that callers are supposed to pre-zero.  The hope is to allow future
addition of more options without either API breakage or a continuing
proliferation of new SPI entry points.  With that in mind, choose
slightly more generic names for them: SPI_execute_extended and
SPI_cursor_parse_open respectively.

Discussion: https://postgr.es/m/CAFj8pRCLPdDAETvR7Po7gC5y_ibkn_-bOzbeJb39WHms01194Q@mail.gmail.com
2021-01-26 16:37:12 -05:00
Fujii Masao
411ae64997 postgres_fdw: Add functions to discard cached connections.
This commit introduces two new functions postgres_fdw_disconnect()
and postgres_fdw_disconnect_all(). The former function discards
the cached connections to the specified foreign server. The latter discards
all the cached connections. If the connection is used in the current
transaction, it's not closed and a warning message is emitted.

For example, these functions are useful when users want to explicitly
close the foreign server connections that are no longer necessary and
then to prevent them from eating up the foreign servers connections
capacity.

Author: Bharath Rupireddy, tweaked a bit by Fujii Masao
Reviewed-by: Alexey Kondratov, Zhijie Hou, Zhihong Yu, Fujii Masao
Discussion: https://postgr.es/m/CALj2ACVvrp5=AVp2PupEm+nAC8S4buqR3fJMmaCoc7ftT0aD2A@mail.gmail.com
2021-01-26 15:35:54 +09:00
Tom Lane
ee895a655c Improve performance of repeated CALLs within plpgsql procedures.
This patch essentially is cleaning up technical debt left behind
by the original implementation of plpgsql procedures, particularly
commit d92bc83c4.  That patch (or more precisely, follow-on patches
fixing its worst bugs) forced us to re-plan CALL and DO statements
each time through, if we're in a non-atomic context.  That wasn't
for any fundamental reason, but just because use of a saved plan
requires having a ResourceOwner to hold a reference count for the
plan, and we had no suitable resowner at hand, nor would the
available APIs support using one if we did.  While it's not that
expensive to create a "plan" for CALL/DO, the cycles do add up
in repeated executions.

This patch therefore makes the following API changes:

* GetCachedPlan/ReleaseCachedPlan are modified to let the caller
specify which resowner to use to pin the plan, rather than forcing
use of CurrentResourceOwner.

* spi.c gains a "SPI_execute_plan_extended" entry point that lets
callers say which resowner to use to pin the plan.  This borrows the
idea of an options struct from the recently added SPI_prepare_extended,
hopefully allowing future options to be added without more API breaks.
This supersedes SPI_execute_plan_with_paramlist (which I've marked
deprecated) as well as SPI_execute_plan_with_receiver (which is new
in v14, so I just took it out altogether).

* I also took the opportunity to remove the crude hack of letting
plpgsql reach into SPI private data structures to mark SPI plans as
"no_snapshot".  It's better to treat that as an option of
SPI_prepare_extended.

Now, when running a non-atomic procedure or DO block that contains
any CALL or DO commands, plpgsql creates a ResourceOwner that
will be used to pin the plans of the CALL/DO commands.  (In an
atomic context, we just use CurrentResourceOwner, as before.)
Having done this, we can just save CALL/DO plans normally,
whether or not they are used across transaction boundaries.
This seems to be good for something like 2X speedup of a CALL
of a trivial procedure with a few simple argument expressions.
By restricting the creation of an extra ResourceOwner like this,
there's essentially zero penalty in cases that can't benefit.

Pavel Stehule, with some further hacking by me

Discussion: https://postgr.es/m/CAFj8pRCLPdDAETvR7Po7gC5y_ibkn_-bOzbeJb39WHms01194Q@mail.gmail.com
2021-01-25 22:28:29 -05:00
Robert Haas
d18e75664a Remove CheckpointLock.
Up until now, we've held this lock when performing a checkpoint or
restartpoint, but commit 076a055acf back
in 2004 and commit 7e48b77b1c from 2009,
taken together, have removed all need for this. In the present code,
there's only ever one process entitled to attempt a checkpoint: either
the checkpointer, during normal operation, or the postmaster, during
single-user operation. So, we don't need the lock.

One possible concern in making this change is that it means that
a substantial amount of code where HOLD_INTERRUPTS() was previously
in effect due to the preceding LWLockAcquire() will now be
running without that. This could mean that ProcessInterrupts()
gets called in places from which it didn't before. However, this
seems unlikely to do very much, because the checkpointer doesn't
have any signal mapped to die(), so it's not clear how,
for example, ProcDiePending = true could happen in the first
place. Similarly with ClientConnectionLost and recovery conflicts.

Also, if there are any such problems, we might want to fix them
rather than reverting this, since running lots of code with
interrupt handling suspended is generally bad.

Patch by me, per an inquiry by Amul Sul. Review by Tom Lane
and Michael Paquier.

Discussion: http://postgr.es/m/CAAJ_b97XnBBfYeSREDJorFsyoD1sHgqnNuCi=02mNQBUMnA=FA@mail.gmail.com
2021-01-25 12:34:38 -05:00
Tom Lane
951862eda5 Doc: improve documentation of pg_proc.protrftypes.
Add a "references" link pointing to pg_type, as we have for other arrays
of type OIDs.  Wordsmith the explanation a bit.

Joel Jacobson, additional editing by me

Discussion: https://postgr.es/m/d1cc628c-3953-4209-957b-29427acc38c8@www.fastmail.com
2021-01-25 11:20:17 -05:00
Tom Lane
7e57255f61 Doc: clean up contrib/pageinspect's GIST function documentation.
I came to fix the overwidth-PDF-page warnings seen in the buildfarm,
but stayed long enough to copy-edit some nearby text.
2021-01-23 22:40:46 -05:00
Tom Lane
183bbd1b6d Doc: update example connection-failure messages in the documentation.
Now that the dust has more or less settled on 52a10224e and follow-ons,
make sure the examples in the documentation are up-to-date.
2021-01-23 15:50:51 -05:00
Tom Lane
50bebc1ae1 Doc: improve directions for building on macOS.
In light of recent discussions, we should instruct people to
install Apple's command line tools; installing Xcode is secondary.

Also, fix sample command for finding out the default sysroot,
as we now know that the command originally recommended can give
a result that doesn't match your OS version.

Also document the workaround to use if you really don't want
configure to select a sysroot at all.

Discussion: https://postgr.es/m/20210119111625.20435-1-james.hilliard1@gmail.com
2021-01-22 18:58:25 -05:00
Tom Lane
58cd8dca3d Avoid redundantly prefixing PQerrorMessage for a connection failure.
libpq's error messages for connection failures pretty well stand on
their own, especially since commits 52a10224e/27a48e5a1.  Prefixing
them with 'could not connect to database "foo"' or the like is just
redundant, and perhaps even misleading if the specific database name
isn't relevant to the failure.  (When it is, we trust that the
backend's error message will include the DB name.)  Indeed, psql
hasn't used any such prefix in a long time.  So, make all our other
programs and documentation examples agree with psql's practice.

Discussion: https://postgr.es/m/1094524.1611266589@sss.pgh.pa.us
2021-01-22 16:52:31 -05:00
Tom Lane
7cd9765f9b Re-allow DISTINCT in pl/pgsql expressions.
I'd omitted this from the grammar in commit c9d529848, figuring that
it wasn't worth supporting.  However we already have one complaint,
so it seems that judgment was wrong.  It doesn't require a huge
amount of code, so add it back.  (I'm still drawing the line at
UNION/INTERSECT/EXCEPT though: those'd require an unreasonable
amount of grammar refactoring, and the single-result-row restriction
makes them near useless anyway.)

Also rethink the documentation: this behavior is a property of
all pl/pgsql expressions, not just assignments.

Discussion: https://postgr.es/m/20210122134106.e94c5cd7@mail.verfriemelt.org
2021-01-22 16:26:22 -05:00
Tom Lane
ab66645628 Doc: remove misleading claim in documentation of PQreset().
This text claimed that the reconnection would occur "to the same
server", but there is no such guarantee in the code, nor would
insisting on that be an improvement.

Back-patch to v10 where multi-host connection strings were added.

Discussion: https://postgr.es/m/1095901.1611268376@sss.pgh.pa.us
2021-01-22 11:29:43 -05:00
Magnus Hagander
0a9ae44288 Remove reference to ftp servers from documentation
It's been a long time since we used ftp, but there was a single
reference left in the docs.

Author: Daniel Gustafsson <daniel@yesql.se>
Discussion: https://postgr.es/m/6880D602-7286-46EC-8A03-14E3248FEC7A@yesql.se
2021-01-22 12:49:53 +01:00
Heikki Linnakangas
29ad6595ef doc: Copy-edit the "Overview of PostgreSQL Internals" chapter
Rephrase a few sentences to be more concise.

Refer to the postmaster process as "postmaster", not "postgres". This
originally said "postmaster process", but was changed to "postgres
process" in commit 5266f221a2, when we merged the "postmaster" and
"postgres" commands, and "postmaster" became just a symlink. That was a
case of overzealous search & replace, because the process is still called
"postmaster".

Author: Erik Rijkers and Jürgen Purtz
Discussion: https://www.postgresql.org/message-id/aa31f359-1168-ded5-53d0-0ed228bfe097%40iki.fi
2021-01-22 11:10:42 +02:00
Tomas Vondra
b663a41363 Implement support for bulk inserts in postgres_fdw
Extends the FDW API to allow batching inserts into foreign tables. That
is usually much more efficient than inserting individual rows, due to
high latency for each round-trip to the foreign server.

It was possible to implement something similar in the regular FDW API,
but it was inconvenient and there were issues with reporting the number
of actually inserted rows etc. This extends the FDW API with two new
functions:

* GetForeignModifyBatchSize - allows the FDW picking optimal batch size

* ExecForeignBatchInsert - inserts a batch of rows at once

Currently, only INSERT queries support batching. Support for DELETE and
UPDATE may be added in the future.

This also implements batching for postgres_fdw. The batch size may be
specified using "batch_size" option both at the server and table level.

The initial patch version was written by me, but it was rewritten and
improved in many ways by Takayuki Tsunakawa.

Author: Takayuki Tsunakawa
Reviewed-by: Tomas Vondra, Amit Langote
Discussion: https://postgr.es/m/20200628151002.7x5laxwpgvkyiu3q@development
2021-01-20 23:57:27 +01:00
Tomas Vondra
ad600bba04 psql \dX: list extended statistics objects
The new command lists extended statistics objects. All past releases
with extended statistics are supported.

This is a simplified version of commit 891a1d0bca, which had to be
reverted due to not considering pg_statistic_ext_data is not accessible
by regular users. Fields requiring access to this catalog were removed.
It's possible to add them, but it'll require changes to core.

Author: Tatsuro Yamada
Reviewed-by: Julien Rouhaud, Alvaro Herrera, Tomas Vondra, Noriyoshi Shinoda
Discussion: https://postgr.es/m/c027a541-5856-75a5-0868-341301e1624b%40nttcom.co.jp_1
2021-01-20 22:57:21 +01:00
Thomas Munro
679744cf1b Fix sample output of EXPLAIN ANALYZE.
Since commit f0f13a3a08, we estimate
ModifyTable paths without a RETURNING clause differently.  Update an
example from the manual that showed the old behavior.

Author: Takayuki Tsunakawa <tsunakawa.takay@fujitsu.com>
Reviewed-by: Laurenz Albe <laurenz.albe@cybertec.at>
Discussion: https://postgr.es/m/TYAPR01MB29905674F41693BBA9DA28CAFEA20%40TYAPR01MB2990.jpnprd01.prod.outlook.com
2021-01-20 22:38:24 +13:00
Peter Eisentraut
f18aa1b203 pageinspect: Change block number arguments to bigint
Block numbers are 32-bit unsigned integers.  Therefore, the smallest
SQL integer type that they can fit in is bigint.  However, in the
pageinspect module, most input and output parameters dealing with
block numbers were declared as int.  The behavior with block numbers
larger than a signed 32-bit integer was therefore dubious.  Change
these arguments to type bigint and add some more explicit error
checking on the block range.

(Other contrib modules appear to do this correctly already.)

Since we are changing argument types of existing functions, in order
to not misbehave if the binary is updated before the extension is
updated, we need to create new C symbols for the entry points, similar
to how it's done in other extensions as well.

Reported-by: Ashutosh Bapat <ashutosh.bapat.oss@gmail.com>
Reviewed-by: Alvaro Herrera <alvherre@alvh.no-ip.org>
Reviewed-by: Michael Paquier <michael@paquier.xyz>
Discussion: https://www.postgresql.org/message-id/flat/d8f6bdd536df403b9b33816e9f7e0b9d@G08CNEXMBPEKD05.g08.fujitsu.local
2021-01-19 11:03:38 +01:00
Fujii Masao
ee79a548e7 doc: Add note about the server name of postgres_fdw_get_connections() returns.
Previously the document didn't mention the case where
postgres_fdw_get_connections() returns NULL in server_name column.
Users might be confused about why NULL was returned.

This commit adds the note that, in postgres_fdw_get_connections(),
the server name of an invalid connection will be NULL if the server is dropped.

Suggested-by: Zhijie Hou
Author: Bharath Rupireddy
Reviewed-by: Zhijie Hou, Fujii Masao
Discussion: https://postgr.es/m/e7ddd14e96444fce88e47a709c196537@G08CNEXMBPEKD05.g08.fujitsu.local
2021-01-19 15:04:58 +09:00
Bruce Momjian
9e7dbe3369 doc: adjust alignment of doc file list for "pg_waldump.sgml"
Backpatch-through: 10
2021-01-18 18:48:25 -05:00
Tom Lane
a6cf3df4eb Add bytea equivalents of ltrim() and rtrim().
We had bytea btrim() already, but for some reason not the other two.

Joel Jacobson

Discussion: https://postgr.es/m/d10cd5cd-a901-42f1-b832-763ac6f7ff3a@www.fastmail.com
2021-01-18 15:11:32 -05:00
Peter Eisentraut
15251c0a60 Pause recovery for insufficient parameter settings
When certain parameters are changed on a physical replication primary,
this is communicated to standbys using the XLOG_PARAMETER_CHANGE WAL
record.  The standby then checks whether its own settings are at least
as big as the ones on the primary.  If not, the standby shuts down
with a fatal error.

This patch changes this behavior for hot standbys to pause recovery at
that point instead.  That allows read traffic on the standby to
continue while database administrators figure out next steps.  When
recovery is unpaused, the server shuts down (as before).  The idea is
to fix the parameters while recovery is paused and then restart when
there is a maintenance window.

Reviewed-by: Sergei Kornilov <sk@zsrv.org>
Discussion: https://www.postgresql.org/message-id/flat/4ad69a4c-cc9b-0dfe-0352-8b1b0cd36c7b@2ndquadrant.com
2021-01-18 09:04:04 +01:00
Fujii Masao
708d165ddb postgres_fdw: Add function to list cached connections to foreign servers.
This commit adds function postgres_fdw_get_connections() to return
the foreign server names of all the open connections that postgres_fdw
established from the local session to the foreign servers. This function
also returns whether each connection is valid or not.

This function is useful when checking all the open foreign server connections.
If we found some connection to drop, from the result of function, probably
we can explicitly close them by the function that upcoming commit will add.

This commit bumps the version of postgres_fdw to 1.1 since it adds
new function.

Author: Bharath Rupireddy, tweaked by Fujii Masao
Reviewed-by: Zhijie Hou, Alexey Kondratov, Zhihong Yu, Fujii Masao
Discussion: https://postgr.es/m/2d5cb0b3-a6e8-9bbb-953f-879f47128faa@oss.nttdata.com
2021-01-18 15:11:08 +09:00
Magnus Hagander
cf621d9d84 Add documentation chapter about checksums
Data checksums did not have a longer discussion in the docs,
this adds a short section with an overview.

Extracted from the larger patch for on-line enabling of checksums, which
has many more authors and reviewers.

Author: Daniel Gustafsson
Reviewed-By: Magnus Hagander, Michael Banck (and others through the big patch)
Discussion: https://postgr.es/m/5ff49fa4.1c69fb81.658f3.04ac@mx.google.com
2021-01-17 15:31:23 +01:00
Tomas Vondra
1db0d173a2 Revert "psql \dX: list extended statistics objects"
Reverts 891a1d0bca, because the new  psql command \dX only worked for
users users who can read pg_statistic_ext_data catalog, and most regular
users lack that privilege (the catalog may contain sensitive user data).

Reported-by: Noriyoshi Shinoda
Discussion: https://postgr.es/m/c027a541-5856-75a5-0868-341301e1624b%40nttcom.co.jp_1
2021-01-17 15:11:14 +01:00
Magnus Hagander
e09155bd62 Add --no-instructions parameter to initdb
Specifying this parameter removes the informational messages about how
to start the server. This is intended for use by wrappers in different
packaging systems, where those instructions would most likely be wrong
anyway, but the other output from initdb would still be useful (and thus
just redirecting everything to /dev/null would be bad).

Author: Magnus Hagander
Reviewed-By: Peter Eisentraut
Discusion: https://postgr.es/m/CABUevEzo4t5bmTXF0_B9WzmuWpVbMpkNZZiGvzV8NZa-=fPqeQ@mail.gmail.com
2021-01-17 14:34:41 +01:00
Magnus Hagander
960869da08 Add pg_stat_database counters for sessions and session time
This add counters for number of sessions, the different kind of session
termination types, and timers for how much time is spent in active vs
idle in a database to pg_stat_database.

Internally this also renames the parameter "force" to disconnect. This
was the only use-case for the parameter before, so repurposing it to
this mroe narrow usecase makes things cleaner than inventing something
new.

Author: Laurenz Albe
Reviewed-By: Magnus Hagander, Soumyadeep Chakraborty, Masahiro Ikeda
Discussion: https://postgr.es/m/b07e1f9953701b90c66ed368656f2aef40cac4fb.camel@cybertec.at
2021-01-17 13:52:31 +01:00
Tomas Vondra
891a1d0bca psql \dX: list extended statistics objects
The new command lists extended statistics objects, possibly with their
sizes. All past releases with extended statistics are supported.

Author: Tatsuro Yamada
Reviewed-by: Julien Rouhaud, Alvaro Herrera, Tomas Vondra
Discussion: https://postgr.es/m/c027a541-5856-75a5-0868-341301e1624b%40nttcom.co.jp_1
2021-01-17 00:16:45 +01:00
Jeff Davis
a32d98351e Documenation fixups for replication protocol.
There is no CopyResponse message; it should be CopyOutResponse.

Also, if there is no WAL to stream, the server does not immediately
send a CommandComplete; it's a historical timeline, so it will send a
response tuple first.

Discussion: https://postgr.es/m/0a2c985ebcaa1acd385350aeba561b6509187394.camel@j-davis.com
2021-01-16 14:40:12 -08:00
Alvaro Herrera
ebfe2dbd6b
Prevent drop of tablespaces used by partitioned relations
When a tablespace is used in a partitioned relation (per commits
ca4103025d in pg12 for tables and 33e6c34c32 in pg11 for indexes),
it is possible to drop the tablespace, potentially causing various
problems.  One such was reported in bug #16577, where a rewriting ALTER
TABLE causes a server crash.

Protect against this by using pg_shdepend to keep track of tablespaces
when used for relations that don't keep physical files; we now abort a
tablespace if we see that the tablespace is referenced from any
partitioned relations.

Backpatch this to 11, where this problem has been latent all along.  We
don't try to create pg_shdepend entries for existing partitioned
indexes/tables, but any ones that are modified going forward will be
protected.

Note slight behavior change: when trying to drop a tablespace that
contains both regular tables as well as partitioned ones, you'd
previously get ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE and now you'll
get ERRCODE_DEPENDENT_OBJECTS_STILL_EXIST.  Arguably, the latter is more
correct.

It is possible to add protecting pg_shdepend entries for existing
tables/indexes, by doing
  ALTER TABLE ONLY some_partitioned_table SET TABLESPACE pg_default;
  ALTER TABLE ONLY some_partitioned_table SET TABLESPACE original_tablespace;
for each partitioned table/index that is not in the database default
tablespace.  Because these partitioned objects do not have storage, no
file needs to be actually moved, so it shouldn't take more time than
what's required to acquire locks.

This query can be used to search for such relations:
SELECT ... FROM pg_class WHERE relkind IN ('p', 'I') AND reltablespace <> 0

Reported-by: Alexander Lakhin <exclusion@gmail.com>
Discussion: https://postgr.es/m/16577-881633a9f9894fd5@postgresql.org
Author: Álvaro Herrera <alvherre@alvh.no-ip.org>
Reviewed-by: Michael Paquier <michael@paquier.xyz>
2021-01-14 15:32:14 -03:00
Alvaro Herrera
93c39f987e
Call out vacuum considerations in create index docs
Backpatch to pg12, which is as far as it goes without conflicts.

Author: James Coleman <jtc331@gmail.com>
Reviewed-by: "David G. Johnston" <david.g.johnston@gmail.com>
Discussion: https://postgr.es/m/CAAaqYe9oEfbz7AxXq7OX+FFVi5w5p1e_Of8ON8ZnKO9QqBfmjg@mail.gmail.com
2021-01-13 17:55:41 -03:00
Tom Lane
c21ea4d53e Disallow a digit as the first character of a variable name in pgbench.
The point of this restriction is to avoid trying to substitute variables
into timestamp literal values, which may contain strings like '12:34'.

There is a good deal more that should be done to reduce pgbench's
tendency to substitute where it shouldn't.  But this is sufficient to
solve the case complained of by Jaime Soler, and it's simple enough
to back-patch.

Back-patch to v11; before commit 9d36a3866, pgbench had a slightly
different definition of what a variable name is, and anyway it seems
unwise to change long-stable branches for this.

Fabien Coelho

Discussion: https://postgr.es/m/alpine.DEB.2.22.394.2006291740420.805678@pseudo
2021-01-13 14:52:59 -05:00
Tom Lane
06ed235ade Doc: clarify behavior of back-half options in pg_dump.
Options that change how the archive data is converted to SQL text
are ignored when dumping to archive formats.  The documentation
previously said "not meaningful", which is not helpful.

Discussion: https://postgr.es/m/161052021249.12228.9598689907884726185@wrigleys.postgresql.org
2021-01-13 13:30:04 -05:00
Peter Geoghegan
d168b66682 Enhance nbtree index tuple deletion.
Teach nbtree and heapam to cooperate in order to eagerly remove
duplicate tuples representing dead MVCC versions.  This is "bottom-up
deletion".  Each bottom-up deletion pass is triggered lazily in response
to a flood of versions on an nbtree leaf page.  This usually involves a
"logically unchanged index" hint (these are produced by the executor
mechanism added by commit 9dc718bd).

The immediate goal of bottom-up index deletion is to avoid "unnecessary"
page splits caused entirely by version duplicates.  It naturally has an
even more useful effect, though: it acts as a backstop against
accumulating an excessive number of index tuple versions for any given
_logical row_.  Bottom-up index deletion complements what we might now
call "top-down index deletion": index vacuuming performed by VACUUM.
Bottom-up index deletion responds to the immediate local needs of
queries, while leaving it up to autovacuum to perform infrequent clean
sweeps of the index.  The overall effect is to avoid certain
pathological performance issues related to "version churn" from UPDATEs.

The previous tableam interface used by index AMs to perform tuple
deletion (the table_compute_xid_horizon_for_tuples() function) has been
replaced with a new interface that supports certain new requirements.
Many (perhaps all) of the capabilities added to nbtree by this commit
could also be extended to other index AMs.  That is left as work for a
later commit.

Extend deletion of LP_DEAD-marked index tuples in nbtree by adding logic
to consider extra index tuples (that are not LP_DEAD-marked) for
deletion in passing.  This increases the number of index tuples deleted
significantly in many cases.  The LP_DEAD deletion process (which is now
called "simple deletion" to clearly distinguish it from bottom-up
deletion) won't usually need to visit any extra table blocks to check
these extra tuples.  We have to visit the same table blocks anyway to
generate a latestRemovedXid value (at least in the common case where the
index deletion operation's WAL record needs such a value).

Testing has shown that the "extra tuples" simple deletion enhancement
increases the number of index tuples deleted with almost any workload
that has LP_DEAD bits set in leaf pages.  That is, it almost never fails
to delete at least a few extra index tuples.  It helps most of all in
cases that happen to naturally have a lot of delete-safe tuples.  It's
not uncommon for an individual deletion operation to end up deleting an
order of magnitude more index tuples compared to the old naive approach
(e.g., custom instrumentation of the patch shows that this happens
fairly often when the regression tests are run).

Add a further enhancement that augments simple deletion and bottom-up
deletion in indexes that make use of deduplication: Teach nbtree's
_bt_delitems_delete() function to support granular TID deletion in
posting list tuples.  It is now possible to delete individual TIDs from
posting list tuples provided the TIDs have a tableam block number of a
table block that gets visited as part of the deletion process (visiting
the table block can be triggered directly or indirectly).  Setting the
LP_DEAD bit of a posting list tuple is still an all-or-nothing thing,
but that matters much less now that deletion only needs to start out
with the right _general_ idea about which index tuples are deletable.

Bump XLOG_PAGE_MAGIC because xl_btree_delete changed.

No bump in BTREE_VERSION, since there are no changes to the on-disk
representation of nbtree indexes.  Indexes built on PostgreSQL 12 or
PostgreSQL 13 will automatically benefit from bottom-up index deletion
(i.e. no reindexing required) following a pg_upgrade.  The enhancement
to simple deletion is available with all B-Tree indexes following a
pg_upgrade, no matter what PostgreSQL version the user upgrades from.

Author: Peter Geoghegan <pg@bowt.ie>
Reviewed-By: Heikki Linnakangas <hlinnaka@iki.fi>
Reviewed-By: Victor Yegorov <vyegorov@gmail.com>
Discussion: https://postgr.es/m/CAH2-Wzm+maE3apHB8NOtmM=p-DO65j2V5GzAWCOEEuy3JZgb2g@mail.gmail.com
2021-01-13 09:21:32 -08:00
Peter Geoghegan
9dc718bdf2 Pass down "logically unchanged index" hint.
Add an executor aminsert() hint mechanism that informs index AMs that
the incoming index tuple (the tuple that accompanies the hint) is not
being inserted by execution of an SQL statement that logically modifies
any of the index's key columns.

The hint is received by indexes when an UPDATE takes place that does not
apply an optimization like heapam's HOT (though only for indexes where
all key columns are logically unchanged).  Any index tuple that receives
the hint on insert is expected to be a duplicate of at least one
existing older version that is needed for the same logical row.  Related
versions will typically be stored on the same index page, at least
within index AMs that apply the hint.

Recognizing the difference between MVCC version churn duplicates and
true logical row duplicates at the index AM level can help with cleanup
of garbage index tuples.  Cleanup can intelligently target tuples that
are likely to be garbage, without wasting too many cycles on less
promising tuples/pages (index pages with little or no version churn).

This is infrastructure for an upcoming commit that will teach nbtree to
perform bottom-up index deletion.  No index AM actually applies the hint
just yet.

Author: Peter Geoghegan <pg@bowt.ie>
Reviewed-By: Victor Yegorov <vyegorov@gmail.com>
Discussion: https://postgr.es/m/CAH2-Wz=CEKFa74EScx_hFVshCOn6AA5T-ajFASTdzipdkLTNQQ@mail.gmail.com
2021-01-13 08:11:00 -08:00
Fujii Masao
39b03690b5 Log long wait time on recovery conflict when it's resolved.
This is a follow-up of the work done in commit 0650ff2303. This commit
extends log_recovery_conflict_waits so that a log message is produced
also when recovery conflict has already been resolved after deadlock_timeout
passes, i.e., when the startup process finishes waiting for recovery
conflict after deadlock_timeout. This is useful in investigating how long
recovery conflicts prevented the recovery from applying WAL.

Author: Fujii Masao
Reviewed-by: Kyotaro Horiguchi, Bertrand Drouvot
Discussion: https://postgr.es/m/9a60178c-a853-1440-2cdc-c3af916cff59@amazon.com
2021-01-13 22:59:17 +09:00
Magnus Hagander
e6eeb8d799 Remove incorrect markup
Seems 737d69ffc3 made a copy/paste or automation error resulting in two
extra right-parenthesis.

Reported-By: Michael Vastola
Backpatch-through: 13
Discussion: https://postgr.es/m/161051035421.12224.1741822783166533529@wrigleys.postgresql.org
2021-01-13 11:07:37 +01:00
Heikki Linnakangas
756ab29124 Add functions to 'pageinspect' to inspect GiST indexes.
Author: Andrey Borodin and me
Discussion: https://www.postgresql.org/message-id/3E4F9093-A1B5-4DF8-A292-0B48692E3954%40yandex-team.ru
2021-01-13 10:33:33 +02:00
Tom Lane
cc865c0f31 Doc: fix description of privileges needed for ALTER PUBLICATION.
Adding a table to a publication requires ownership of the table
(in addition to ownership of the publication).  This was mentioned
nowhere.
2021-01-12 12:52:14 -05:00
Bruce Momjian
01334c92fa doc: expand description of how non-SELECT queries are processed
The previous description of how the executor processes non-SELECT
queries was very dense, causing lack of clarity.  This expanded text
spells it out more simply.

Reported-by: fotis.koutoupas@gmail.com

Discussion: https://postgr.es/m/160912275508.676.17469511338925622905@wrigleys.postgresql.org

Backpatch-through: 9.5
2021-01-09 12:11:16 -05:00
Tomas Vondra
ebb5457cfa Minor fixes in COPY progress docs
Author: Justin Pryzby
Discussion: https://postgr.es/m/CAFp7Qwr6_FmRM6pCO0x_a0mymOfX_Gg+FEKet4XaTGSW=LitKQ@mail.gmail.com
2021-01-07 17:33:00 +01:00
Fujii Masao
0650ff2303 Add GUC to log long wait times on recovery conflicts.
This commit adds GUC log_recovery_conflict_waits that controls whether
a log message is produced when the startup process is waiting longer than
deadlock_timeout for recovery conflicts. This is useful in determining
if recovery conflicts prevent the recovery from applying WAL.

Note that currently a log message is produced only when recovery conflict
has not been resolved yet even after deadlock_timeout passes, i.e.,
only when the startup process is still waiting for recovery conflict
even after deadlock_timeout.

Author: Bertrand Drouvot, Masahiko Sawada
Reviewed-by: Alvaro Herrera, Kyotaro Horiguchi, Fujii Masao
Discussion: https://postgr.es/m/9a60178c-a853-1440-2cdc-c3af916cff59@amazon.com
2021-01-08 00:47:03 +09:00
Tom Lane
9877374bef Add idle_session_timeout.
This GUC variable works much like idle_in_transaction_session_timeout,
in that it kills sessions that have waited too long for a new client
query.  But it applies when we're not in a transaction, rather than
when we are.

Li Japin, reviewed by David Johnston and Hayato Kuroda, some
fixes by me

Discussion: https://postgr.es/m/763A0689-F189-459E-946F-F0EC4458980B@hotmail.com
2021-01-06 18:28:52 -05:00
Tomas Vondra
8a4f618e7a Report progress of COPY commands
This commit introduces a view pg_stat_progress_copy, reporting progress
of COPY commands.  This allows rough estimates how far a running COPY
progressed, with the caveat that the total number of bytes may not be
available in some cases (e.g. when the input comes from the client).

Author: Josef Šimánek
Reviewed-by: Fujii Masao, Bharath Rupireddy, Vignesh C, Matthias van de Meent
Discussion: https://postgr.es/m/CAFp7QwqMGEi4OyyaLEK9DR0+E+oK3UtA4bEjDVCa4bNkwUY2PQ@mail.gmail.com
Discussion: https://postgr.es/m/CAFp7Qwr6_FmRM6pCO0x_a0mymOfX_Gg+FEKet4XaTGSW=LitKQ@mail.gmail.com
2021-01-06 21:51:06 +01:00
Peter Eisentraut
4656e3d668 Replace CLOBBER_CACHE_ALWAYS with run-time GUC
Forced cache invalidation (CLOBBER_CACHE_ALWAYS) has been impractical
to use for testing in PostgreSQL because it's so slow and because it's
toggled on/off only at build time.  It is helpful when hunting bugs in
any code that uses the sycache/relcache because causes cache
invalidations to be injected whenever it would be possible for an
invalidation to occur, whether or not one was really pending.

Address this by providing run-time control over cache clobber
behaviour using the new debug_invalidate_system_caches_always GUC.
Support is not compiled in at all unless assertions are enabled or
CLOBBER_CACHE_ENABLED is explicitly defined at compile time.  It
defaults to 0 if compiled in, so it has negligible effect on assert
build performance by default.

When support is compiled in, test code can now set
debug_invalidate_system_caches_always=1 locally to a backend to test
specific queries, functions, extensions, etc.  Or tests can toggle it
globally for a specific test case while retaining normal performance
during test setup and teardown.

For backwards compatibility with existing test harnesses and scripts,
debug_invalidate_system_caches_always defaults to 1 if
CLOBBER_CACHE_ALWAYS is defined, and to 3 if CLOBBER_CACHE_RECURSIVE
is defined.

CLOBBER_CACHE_ENABLED is now visible in pg_config_manual.h, as is the
related RECOVER_RELATION_BUILD_MEMORY setting for the relcache.

Author: Craig Ringer <craig.ringer@2ndquadrant.com>
Discussion: https://www.postgresql.org/message-id/flat/CAMsr+YF=+ctXBZj3ywmvKNUjWpxmuTuUKuv-rgbHGX5i5pLstQ@mail.gmail.com
2021-01-06 10:46:44 +01:00
Fujii Masao
25dde58357 doc: Fix description about default behavior of recovery_target_timeline.
The default value of recovery_target_timeline was changed in v12,
but the description about the default behavior of that was not updated.

Back-patch to v12 where the default behavior of recovery_target_timeline
was changed.

Author: Benoit Lobréau
Reviewed-by: Fujii Masao
Discussion: https://postgr.es/m/CAPE8EZ7c3aruEmM24GYkj8y8WmHKD1m9TtPtgCF0nQ3zw4LCkQ@mail.gmail.com
2021-01-06 11:58:23 +09:00