If ANALYZE found no repeated non-null entries in its sample, it set the
column's stadistinct value to -1.0, intending to indicate that the entries
are all distinct. But what this value actually means is that the number
of distinct values is 100% of the table's rowcount, and thus it was
overestimating the number of distinct values by however many nulls there
are. This could lead to very poor selectivity estimates, as for example
in a recent report from Andreas Joseph Krogh. We should discount the
stadistinct value by whatever we've estimated the nulls fraction to be.
(That is what will happen if we choose to use a negative stadistinct for
a column that does have repeated entries, so this code path was just
inconsistent.)
In addition to fixing the stadistinct entries stored by several different
ANALYZE code paths, adjust the logic where get_variable_numdistinct()
forces an "all distinct" estimate on the basis of finding a relevant unique
index. Unique indexes don't reject nulls, so there's no reason to assume
that the null fraction doesn't apply.
Back-patch to all supported branches. Back-patching is a bit of a judgment
call, but this problem seems to affect only a few users (else we'd have
identified it long ago), and it's bad enough when it does happen that
destabilizing plan choices in a worse direction seems unlikely.
Patch by me, with documentation wording suggested by Dean Rasheed
Report: <VisenaEmail.26.df42f82acae38a58.156463942b8@tc7-visena>
Discussion: <16143.1470350371@sss.pgh.pa.us>
This is required for the result to be a legal tsvector value.
Noted while fooling with Andreas Seltenreich's ts_delete() crash.
Discussion: <87invhoj6e.fsf@credativ.de>
This reverts the spaces before k/M/G/TB units removed for consistency in
commit ca0c37b56f4a80ad758774e34c86cc4335583d29.
Discussion: 20160802165116.GC32575@momjian.us
The help message for pg_basebackup specifies that the numbers 0 through 9
are accepted as valid values of -Z option. But, previously -Z 0 was rejected
as an invalid compression level.
Per discussion, it's better to make pg_basebackup treat 0 as valid
compression level meaning no compression, like pg_dump.
Back-patch to all supported versions.
Reported-By: Jeff Janes
Reviewed-By: Amit Kapila
Discussion: CAMkU=1x+GwjSayc57v6w87ij6iRGFWt=hVfM0B64b1_bPVKRqg@mail.gmail.com
This text was added by commit ff213239c, and not long thereafter obsoleted
by commit 4adc2f72a (which made the test depend on NBuffers instead); but
nobody noticed the need for an update. Commit 9563d5b5e adds some further
dependency on maintenance_work_mem, but the existing verbiage seems to
cover that with about as much precision as we really want here. Let's
just take it all out rather than leaving ourselves open to more errors of
omission in future. (That solution makes this change back-patchable, too.)
Noted by Peter Geoghegan.
Discussion: <CAM3SWZRVANbj9GA9j40fAwheQCZQtSwqTN1GBTVwRrRbmSf7cg@mail.gmail.com>
The docs failed to explain that LIKE INCLUDING INDEXES would not preserve
the names of indexes and associated constraints. Also, it wasn't mentioned
that EXCLUDE constraints would be copied by this option. The latter
oversight seems enough of a documentation bug to justify back-patching.
In passing, do some minor copy-editing in the same area, and add an entry
for LIKE under "Compatibility", since it's not exactly a faithful
implementation of the standard's feature.
Discussion: <20160728151154.AABE64016B@smtp.hushmail.com>
The description of udt_privileges view contained an incorrect copy-pasted word.
Back-patch to 9.2 where udt_privileges view was added.
Author: Alexander Law
The SQL standard appears to specify that IS [NOT] NULL's tests of field
nullness are non-recursive, ie, we shouldn't consider that a composite
field with value ROW(NULL,NULL) is null for this purpose.
ExecEvalNullTest got this right, but eval_const_expressions did not,
leading to weird inconsistencies depending on whether the expression
was such that the planner could apply constant folding.
Also, adjust the docs to mention that IS [NOT] DISTINCT FROM NULL can be
used as a substitute test if a simple null check is wanted for a rowtype
argument. That motivated reordering things so that IS [NOT] DISTINCT FROM
is described before IS [NOT] NULL. In HEAD, I went a bit further and added
a table showing all the comparison-related predicates.
Per bug #14235. Back-patch to all supported branches, since it's certainly
undesirable that constant-folding should change the semantics.
Report and patch by Andrew Gierth; assorted wordsmithing and revised
regression test cases by me.
Report: <20160708024746.1410.57282@wrigleys.postgresql.org>
These functions were added in commits fbe5a3fb7 and a104a017f,
but commit 45639a052 removed their only callers. Put the related
code in foreign.c back to the way it was in 9.5, to avoid pointless
cross-version diffs.
Etsuro Fujita
Patch: <d674a3f1-6b63-519c-ef3f-f3188ed6a178@lab.ntt.co.jp>
9.4 added a second description of GET DIAGNOSTICS that was totally
independent of the existing one, resulting in each description lying to the
extent that it claimed the set of status items it described was complete.
Fix that, and do some minor markup improvement.
Also some other small fixes per bug #14258 from Dilian Palauzov.
Discussion: <20160718181437.1414.40802@wrigleys.postgresql.org>
brin-extensibility-inclusion-table was confused in places about the
difference between strategy 4 (RTOverRight) and strategy 5 (RTRight).
Alexander Law
To ensure that "make installcheck" can be used safely against an existing
installation, we need to be careful about what global object names
(database, role, and tablespace names) we use; otherwise we might
accidentally clobber important objects. There's been a weak consensus that
test databases should have names including "regression", and that test role
names should start with "regress_", but we didn't have any particular rule
about tablespace names; and neither of the other rules was followed with
any consistency either.
This commit moves us a long way towards having a hard-and-fast rule that
regression test databases must have names including "regression", and that
test role and tablespace names must start with "regress_". It's not
completely there because I did not touch some test cases in rolenames.sql
that test creation of special role names like "session_user". That will
require some rethinking of exactly what we want to test, whereas the intent
of this patch is just to hit all the cases in which the needed renamings
are cosmetic.
There is no enforcement mechanism in this patch either, but if we don't
add one we can expect that the tests will soon be violating the convention
again. Again, that's not such a cosmetic change and it will require
discussion. (But I did use a quick-hack enforcement patch to find these
cases.)
Discussion: <16638.1468620817@sss.pgh.pa.us>
For some reason this option wasn't discussed at all in client-auth.sgml.
Document it there, and be more explicit about its relationship to the
"cert" authentication method. Per gripe from Srikanth Venkatesh.
I failed to resist the temptation to do some minor wordsmithing in the
same area, too.
Discussion: <20160713110357.1410.30407@wrigleys.postgresql.org>
Clarify that the reason for recommending that pg_temp be put last is to
prevent temporary tables from capturing unqualified table names. Per
discussion with Albe Laurenz.
Discussion: <A737B7A37273E048B164557ADEF4A58B5386C6E1@ntex2010i.host.magwien.gv.at>
Add display of proparallel (parallel-safety) when the server is >= 9.6,
and display of proacl (access privileges) for all server versions.
Minor tweak of column ordering to keep related columns together.
Michael Paquier
Discussion: <CAB7nPqTR3Vu3xKOZOYqSm-+bSZV0kqgeGAXD6w5GLbkbfd5Q6w@mail.gmail.com>
temp_file_limit is a per-process limit, not a per-session limit across
all cooperating parallel processes; change wording accordingly, per a
suggestion from Tom Lane.
Also, document under max_parallel_workers_per_gather the fact that each
process involved in a parallel query may use as many resources as a
separate session. Caveat emptor.
Per a complaint from Peter Geoghegan.
Per discussion on pgsql-hackers, conninfo is better as the column name
because it's more commonly used in PostgreSQL.
Catalog version bumped due to the change of pg_proc.
Author: Michael Paquier
