A few questionable partitioning designs have been cropping up lately
around the mailing lists. Generally, these cases have been partitioning
using too many partitions which have caused performance or OOM problems for
the users.
Since we have very little else to guide users into good design, here we
add a new section to the partitioning documentation with some best
practise guidelines for good design.
Reviewed-by: Justin Pryzby, Amit Langote, Alvaro Herrera
Discussion: https://postgr.es/m/CAKJS1f-2rx+E9mG3xrCVHupefMjAp1+tpczQa9SEOZWyU7fjEA@mail.gmail.com
Backpatch-through: 10
json_to_record(), when an output column is declared as type json or jsonb,
should emit the corresponding field of the input JSON object. But it got
this slightly wrong when the field is just a string literal: it failed to
escape the contents of the string. That typically resulted in syntax
errors if the string contained any double quotes or backslashes.
jsonb_to_record() handles such cases correctly, but I added corresponding
test cases for it too, to prevent future backsliding.
Improve the documentation, as it provided only a very hand-wavy
description of the conversion rules used by these functions.
Per bug report from Robert Vollmert. Back-patch to v10 where the
error was introduced (by commit cf35346e8).
Note that PG 9.4 - 9.6 also get this case wrong, but differently so:
they feed the de-escaped contents of the string literal to json[b]_in.
That behavior is less obviously wrong, so possibly it's being depended on
in the field, so I won't risk trying to make the older branches behave
like the newer ones.
Discussion: https://postgr.es/m/D6921B37-BD8E-4664-8D5F-DB3525765DCD@vllmrt.net
Removing shared memory and semaphores in response to server start
failure often masks the real problem, a live process associated with the
data directory; see commit 5a907404b5.
Since 9.6, it's rarely necessary to kill subprocesses manually. (When
it is necessary, that commit's HINT will say as much, in all supported
versions.)
Continuous operation cannot be achieved without applying this technique,
so it needs to be properly described.
Author: Álvaro Herrera
Reported-by: Tom Lane
Discussion: https://postgr.es/m/8756.1556302759@sss.pgh.pa.us
Support of CHECK OPTION for updatable views has been added in 9.4, but
the documentation of information_schema never got the call even if the
information displayed is correct.
Author: Gilles Darold
Discussion: https://postgr.es/m/75d07704-6c74-4f26-656a-10045c01a17e@darold.net
Backpatch-through: 9.4
This makes the tool consistent with the option set of oid2name, which
has been historically using -f for filenodes, and has more recently
gained long options and --filenode via 1aaf532.
Reported-by: Peter Eisentraut
Author: Fabien Coelho
Discussion: https://postgr.es/m/97045260-fb9e-e145-a950-cf7d28c4eaea@2ndquadrant.com
This got forgotten in f56f8f which has added foreign key support for
partitioned tables. In passing, add a mention about caveats applying to
tables partitioned using inheritance regarding indexes and foreign keys.
Author: Paul A Jungwirth
Reviewed-by: Amit Langote, Michael Paquier
Discussion: https://postgr.es/m/CA+renyUuSmYgmZjKc_DfUNVZ0uttF91-FwhDVW3F7WEPj0jL5w@mail.gmail.com
Commit 41b54ba78e allowed not only VACUUM but also ANALYZE options
to take a boolean argument. But it forgot to update the documentation
for ANALYZE. This commit adds the descriptions about those ANALYZE
boolean options into the documentation.
This patch also updates tab-completion for ANALYZE boolean options.
Reported-by: Kyotaro Horiguchi
Author: Fujii Masao
Reviewed-by: Masahiko Sawada, Michael Paquier
Discussion: https://postgr.es/m/CAHGQGwHTUt-kuwgiwe8f0AvTnB+ySqJWh95jvmh-qcoKW9YA9g@mail.gmail.com
Define the meanings of the POSIX-spec character classes in line,
rather than referring to the ctype(3) man page. That man page
doesn't even exist on many modern systems, and if it does exist
it probably says the wrong things about non-ASCII characters.
Also document our non-POSIX-spec "ascii" character class.
Also, point out here that this behavior is controlled by collation or
LC_CTYPE, since the existing text explaining that is pretty far away.
Per gripe from Geert Lobbestael. Given the lack of prior complaints,
I'm not excited about back-patching this.
Discussion: https://postgr.es/m/155837022049.1359.2948065118562813468@wrigleys.postgresql.org
It appears that some variants of .** jsonpath accessor are undocumented. In
particular undocumented variants are:
.**{level}
.**{lower_level to upper_level}
.**{lower_level to last}
This commit adds missing documentation for them.
SQL's regular-expression substring() function is defined to have a
pattern argument that's separated into three subpatterns by escape-
double-quote markers; the function result is the part of the input
matching the second subpattern. The standard makes it clear that
if there is ambiguity about how to match the input to the subpatterns,
the first and third subpatterns should be taken to match the smallest
possible amount of text (i.e., they're "non greedy", in the terms of
our regex code). We were not doing it that way: the first subpattern
would eat the largest possible amount of text, causing the function
result to be shorter than what the spec requires.
Fix that by attaching explicit greediness quantifiers to the
subpatterns. (This depends on the regex fix in commit 8a29ed053;
before that, this didn't reliably change the regex engine's behavior.)
Also, by adding parentheses around each subpattern, we ensure that
"|" (OR) in the subpatterns behave sanely. Previously, "|" in the
first or third subpatterns didn't work.
This patch also makes the function throw error if you write more than
two escape-double-quote markers, and do something sane if you write
just one, and document that behavior. Previously, an odd number of
markers led to a confusing complaint about unbalanced parentheses,
while extra pairs of markers were just ignored. (Note that the spec
requires exactly two markers, but we've historically allowed there
to be none, and this patch preserves the old behavior for that case.)
In passing, adjust some substring() test cases that didn't really
prove what they said they were testing for: they used patterns
that didn't match the data string, so that the output would be
NULL whether or not the function was really strict.
Although this is certainly a bug fix, changing the behavior in back
branches seems undesirable: applications could perhaps be depending on
the old behavior, since it's not obviously wrong unless you read the
spec very closely. Hence, no back-patch.
Discussion: https://postgr.es/m/5bb27a41-350d-37bf-901e-9d26f5592dd0@charter.net
Per previous convention (see
ace397e9d2), drop SQL:2008 and only keep
the latest two standards and SQL-92.
Note: SQL:2016-2 lists a large number of non-reserved keywords that
are really just information_schema column names related to new
features. Those kinds of thing have not previously been listed as
keywords, and this was apparently done here by mistake, since these
keywords have been removed again in post-2016 working drafts. So in
order to avoid bloating the keywords table unnecessarily, I have
omitted these erroneous keywords here.
An upcoming HEAD-only patch will standardize the terminology around
ItemIdData variables/line pointers, ending the practice of referring to
them as "item pointers". Make the "Database Page Layout" docs
consistent with the new policy. The term "item identifier" is already
used in the same section, so stick with that.
Discussion: https://postgr.es/m/CAH2-Wz=c=MZQjUzde3o9+2PLAPuHTpVZPPdYxN=E4ndQ2--8ew@mail.gmail.com
Backpatch: All supported branches.
Previously it's documented that use of replication functions is
restricted to superusers. This is true for the functions which
use replication origin, but not for pg_logicl_emit_message() and
functions which use replication slot. For example, not only
superusers but also users with REPLICATION privilege is allowed
to use the functions for replication slot. This commit fixes
the documentation for the privileges required for those replication
functions.
Back-patch to 9.4 (all supported versions).
Author: Matsumura Ryo
Discussion: https://postgr.es/m/03040DFF97E6E54E88D3BFEE5F5480F74ABA6E16@G01JPEXMBYT04
Word "singleton" is hard for user understanding, especially taking into account
there is only one place it's used in the docs and there is even no definition.
Use more evident wording instead.
Discussion: https://postgr.es/m/23737.1556550645%40sss.pgh.pa.us
This commit adds new parameter to VACUUM command, TRUNCATE,
which specifies that VACUUM should attempt to truncate off
any empty pages at the end of the table and allow the disk space
for the truncated pages to be returned to the operating system.
This parameter, if specified, overrides the vacuum_truncate
reloption. If neither the reloption nor the VACUUM option is
used, the default is true, as before.
Author: Fujii Masao
Reviewed-by: Julien Rouhaud, Masahiko Sawada
Discussion: https://postgr.es/m/CAD21AoD+qtrSDL=GSma4Wd3kLYLeRC0hPna-YAdkDeV4z156vg@mail.gmail.com
The SQL keywords table in the documentation had until now been
generated by some ad hoc scripting outside the source tree once for
each major release. This changes it to an automated process.
We have the PostgreSQL keywords available in a parseable format in
parser/kwlist.h. For the relevant SQL standard versions, keep the
keyword lists in new text files. A new script
generate-keywords-table.pl pulls it all together and produces a
DocBook table.
The final output in the documentation should be identical after this
change.
Discussion: https://www.postgresql.org/message-id/flat/07daeadd-8c82-0d95-5e19-e350502cb749%402ndquadrant.com
This feature was using a process local map to track the first few blocks
in the relation. The map was reset each time we get the block with enough
freespace. It was discussed that it would be better to track this map on
a per-relation basis in relcache and then invalidate the same whenever
vacuum frees up some space in the page or when FSM is created. The new
design would be better both in terms of API design and performance.
List of commits reverted, in reverse chronological order:
06c8a5090e Improve code comments in b0eaa4c51b.
13e8643bfc During pg_upgrade, conditionally skip transfer of FSMs.
6f918159a9 Add more tests for FSM.
9c32e4c350 Clear the local map when not used.
29d108cdec Update the documentation for FSM behavior..
08ecdfe7e5 Make FSM test portable.
b0eaa4c51b Avoid creation of the free space map for small heap relations.
Discussion: https://postgr.es/m/20190416180452.3pm6uegx54iitbt5@alap3.anarazel.de
The interaction of these parameters was a bit confused/confusing,
and in fact v11 entirely misses the opportunity to apply partition
constraints when a partition is accessed directly (rather than
indirectly from its parent).
In HEAD, establish the principle that enable_partition_pruning controls
partition pruning and nothing else. When accessing a partition via its
parent, we do partition pruning (if enabled by enable_partition_pruning)
and then there is no need to consider partition constraints in the
constraint_exclusion logic. When accessing a partition directly, its
partition constraints are applied by the constraint_exclusion logic,
only if constraint_exclusion = on.
In v11, we can't have such a clean division of these GUCs' effects,
partly because we don't want to break compatibility too much in a
released branch, and partly because the clean coding requires
inheritance_planner to have applied partition pruning to a partitioned
target table, which it doesn't in v11. However, we can tweak things
enough to cover the missed case, which seems like a good idea since
it's potentially a performance regression from v10. This patch keeps
v11's previous behavior in which enable_partition_pruning overrides
constraint_exclusion for an inherited target table, though.
In HEAD, also teach relation_excluded_by_constraints that it's okay to use
inheritable constraints when trying to prune a traditional inheritance
tree. This might not be thought worthy of effort given that that feature
is semi-deprecated now, but we have enough infrastructure that it only
takes a couple more lines of code to do it correctly.
Amit Langote and Tom Lane
Discussion: https://postgr.es/m/9813f079-f16b-61c8-9ab7-4363cab28d80@lab.ntt.co.jp
Discussion: https://postgr.es/m/29069.1555970894@sss.pgh.pa.us
This fixes a couple of grammar mistakes, typos and inconsistencies in
the documentation. Particularly, the configuration parsing allows only
"kB" to mean kilobyte but there were references in the docs to "KB".
Some instances of the latter are still in the code comments. Some
parameter values were mentioned with "Minus-one", and using directly
"-1" with proper markups is more helpful to the reader.
Some of these have been pointed out by Justin, and some others are
things I bumped into.
Author: Justin Pryzby, Michael Paquier
Reviewed-by: Tom Lane
Discussion: https://postgr.es/m/20190330224333.GQ5815@telsasoft.com
Recently added guidance on adding SVG images to the documentation
sources lacks advice on making the images responsive when rendered
in a variety of media types and viewports. Add some.
Patch by Jonathan Katz with some editorialization by me.
Author: Jonathan Katz
Discussion: https://postgr.es/m/6358ae6f-7191-a02b-e7b5-68050636ae71@postgresql.org
The documentation includes a section about index maintenance and
reindexing, mentioning a set of steps based on CREATE INDEX CONCURRENTLY
and ALTER TABLE (for constraint dependencies) to emulate REINDEX
CONCURRENTLY. Now that REINDEX CONCURRENTLY is supported, let's just
directly mention it instead.
Reported-by: Peter Geoghegan
Author: Michael Paquier
Reviewed-by: Peter Eisentraut, Tom Lane
Discussion: https://postgr.es/m/CAH2-WzmEL168t6w29aKrKXtpq9-apcmp0HC7K-fKt6ZgLXV6Dg@mail.gmail.com
Commit ca4103025d left a few loose ends. The most important one
(broken pg_dump output) is already fixed by virtue of commit
3b23552ad8, but some things remained:
* When ALTER TABLE rewrites tables, the indexes must remain in the
tablespace they were originally in. This didn't work because
index recreation during ALTER TABLE runs manufactured SQL (yuck),
which runs afoul of default_tablespace in competition with the parent
relation tablespace. To fix, reset default_tablespace to the empty
string temporarily, and add the TABLESPACE clause as appropriate.
* Setting a partitioned rel's tablespace to the database default is
confusing; if it worked, it would direct the partitions to that
tablespace regardless of default_tablespace. But in reality it does
not work, and making it work is a larger project. Therefore, throw
an error when this condition is detected, to alert the unwary.
Add some docs and tests, too.
Author: Álvaro Herrera
Discussion: https://postgr.es/m/CAKJS1f_1c260nOt_vBJ067AZ3JXptXVRohDVMLEBmudX1YEx-A@mail.gmail.com
Commit 3d956d9562 added support for update row movement in postgres_fdw.
This patch fixes the following issues introduced by that commit:
* When a remote partition chosen to insert routed rows into was also an
UPDATE subplan target rel that would be updated later, the UPDATE that
used a direct modification plan modified those routed rows incorrectly
because those routed rows were visible to the later UPDATE command.
The right fix for this would be to have some way in postgres_fdw in
which the later UPDATE command ignores those routed rows, but it seems
hard to do so with the current infrastructure. For now throw an error
in that case.
* When a remote partition chosen to insert routed rows into was also an
UPDATE subplan target rel, fmstate created for the UPDATE that used a
non-direct modification plan was mistakenly overridden by another
fmstate created for inserting those routed rows into the partition.
This caused 1) server crash when the partition would be updated later,
and 2) resource leak when the partition had been already updated. To
avoid that, adjust the treatment of the fmstate for the inserting. As
for #1, since we would also have the incorrectness issue as mentioned
above, error out in that case as well.
Update the docs to mention that postgres_fdw currently does not handle
the case where a remote partition chosen to insert a routed row into is
also an UPDATE subplan target rel that will be updated later.
Author: Amit Langote and Etsuro Fujita
Reviewed-by: Amit Langote
Backpatch-through: 11 where row movement in postgres_fdw was added
Discussion: https://postgr.es/m/21e7eaa4-0d4d-20c2-a1f7-c7e96f4ce440@lab.ntt.co.jp
This commit adds the description that "non-exclusive" pg_start_backup
and pg_stop_backup can be executed even during recovery. Previously
it was wrongly documented that those functions are not allowed to be
executed during recovery.
Back-patch to 9.6 where non-exclusive backup API was added.
Discussion: https://postgr.es/m/CAHGQGwEuAYrEX7Yhmf2MCrTK81HDkkg-JqsOUh8zw6+zYC5zzw@mail.gmail.com