Commit Graph

19576 Commits

Author SHA1 Message Date
Noah Misch 459c3cdb4a Don't read fields of a misaligned ExpandedObjectHeader or AnyArrayType.
UBSan complains about this.  Instead, cast to a suitable type requiring
only 4-byte alignment.  DatumGetAnyArrayP() already assumes one can cast
between AnyArrayType and ArrayType, so this doesn't introduce a new
assumption.  Back-patch to 9.5, where AnyArrayType was introduced.

Reviewed by Tom Lane.

Discussion: https://postgr.es/m/20190629210334.GA1244217@rfd.leadboat.com
2019-06-30 17:34:17 -07:00
Andrew Gierth da53be23d1 Repair logic for reordering grouping sets optimization.
The logic in reorder_grouping_sets to order grouping set elements to
match a pre-specified sort ordering was defective, resulting in
unnecessary sort nodes (though the query output would still be
correct). Repair, simplifying the code a little, and add a test.

Per report from Richard Guo, though I didn't use their patch. Original
bug seems to have been my fault.

Backpatch back to 9.5 where grouping sets were introduced.

Discussion: https://postgr.es/m/CAN_9JTzyjGcUjiBHxLsgqfk7PkdLGXiM=pwM+=ph2LsWw0WO1A@mail.gmail.com
2019-06-30 23:49:13 +01:00
Peter Eisentraut 2e810508f6 Fix breakage introduced in pg_lsn_in()
Using PG_RETURN_LSN() from non-fmgr pg_lsn_in_internal() happened to
work on some platforms, but should just be a plain "return".
2019-06-30 13:25:33 +02:00
Peter Eisentraut 21f428ebde Don't call data type input functions in GUC check hooks
Instead of calling pg_lsn_in() in check_recovery_target_lsn and
timestamptz_in() in check_recovery_target_time, reorganize the
respective code so that we don't raise any errors in the check hooks.
The previous code tried to use PG_TRY/PG_CATCH to handle errors in a
way that is not safe, so now the code contains no ereport() calls and
can operate safely within the GUC error handling system.

Moreover, since the interpretation of the recovery_target_time string
may depend on the time zone, we cannot do the final processing of that
string until all the GUC processing is done.  Instead,
check_recovery_target_time() now does some parsing for syntax
checking, but the actual conversion to a timestamptz value is done
later in the recovery code that uses it.

Reported-by: Andres Freund <andres@anarazel.de>
Reviewed-by: Michael Paquier <michael@paquier.xyz>
Discussion: https://www.postgresql.org/message-id/flat/20190611061115.njjwkagvxp4qujhp%40alap3.anarazel.de
2019-06-30 10:27:43 +02:00
Peter Eisentraut 666cbae16d Remove explicit error handling for obsolete date/time values
The date/time values 'current', 'invalid', and 'undefined' were
removed a long time ago, but the code still contains explicit error
handling for the transition.  To simplify the code and avoid having to
handle these values everywhere, just remove the recognition of these
tokens altogether now.

Reviewed-by: Michael Paquier <michael@paquier.xyz>
2019-06-30 10:27:35 +02:00
Tom Lane 54100f5c60 Add an enforcement mechanism for global object names in regression tests.
In commit 18555b132 we tentatively established a rule that regression
tests should use names containing "regression" for databases, and names
starting with "regress_" for all other globally-visible object names, so
as to circumscribe the side-effects that "make installcheck" could have
on an existing installation.

This commit adds a simple enforcement mechanism for that rule: if the code
is compiled with ENFORCE_REGRESSION_TEST_NAME_RESTRICTIONS defined, it
will emit a warning (not an error) whenever a database, role, tablespace,
subscription, or replication origin name is created that doesn't obey the
rule.  Running one or more buildfarm members with that symbol defined
should be enough to catch new violations, at least in the regular
regression tests.  Most TAP tests wouldn't notice such warnings, but
that's actually fine because TAP tests don't execute against an existing
server anyway.

Since it's already the case that running src/test/modules/ tests in
installcheck mode is deprecated, we can use that as a home for tests
that seem unsafe to run against an existing server, such as tests that
might have side-effects on existing roles.  Document that (though this
commit doesn't in itself make it any less safe than before).

Update regress.sgml to define these restrictions more clearly, and
to clean up assorted lack-of-up-to-date-ness in its descriptions of
the available regression tests.

Discussion: https://postgr.es/m/16638.1468620817@sss.pgh.pa.us
2019-06-29 11:34:00 -04:00
Tom Lane a1e61badf9 Disallow user-created replication origins named "pg_xxx".
Since we generate such names internally, it seems like a good idea
to have a policy of disallowing them for user use, as we do for many
other object types.  Otherwise attempts to use them will randomly
fail due to collisions with internally-generated names.

Discussion: https://postgr.es/m/3606.1561747369@sss.pgh.pa.us
2019-06-29 10:30:08 -04:00
Michael Paquier c0faa72750 Remove unnecessary header from be-secure-gssapi.c
libpq/libpq-be.h is included by libpq/libpq.h so there is no need to
explicitly include it separately.

Author: Daniel Gustafsson
Reviewed-by: Julien Rouhaud
Discussion: https://postgr.es/m/A4852E46-9ED1-4861-A23B-22A83E34A084@yesql.se
2019-06-29 11:17:37 +09:00
Alvaro Herrera 23cccb17fe Fix for dropped columns in a partitioned table's default partition
We forgot to map column numbers to/from the default partition for
various operations, leading to valid cases failing with spurious
errors, such as
ERROR:  attribute N of type some_partition has been dropped

It was also possible that the search for conflicting rows in the default
partition when attaching another partition would fail to detect some.
Secondarily, it was also possible that such a search should be skipped
(because the constraint was implied) but wasn't.

Fix all this by mapping column numbers when necessary.

Reported by: Daniel Wilches
Author: Amit Langote
Discussion: https://postgr.es/m/15873-8c61945d6b3ef87c@postgresql.org
2019-06-28 14:51:08 -04:00
Thomas Munro 74b7cc8c02 Fix misleading comment in nodeIndexonlyscan.c.
The stated reason for acquiring predicate locks on heap pages hasn't
existed since commit c01262a8, so fix the comment.  Perhaps in a later
release we'll also be able to change the code to use tuple locks.

Back-patch all the way.

Reviewed-by: Ashwin Agrawal
Discussion: https://postgr.es/m/CAEepm%3D2GK3FVdnt5V3d%2Bh9njWipCv_fNL%3DwjxyUhzsF%3D0PcbNg%40mail.gmail.com
2019-06-28 17:13:08 +12:00
Tomas Vondra 69fd82fedd Update reference to sampling algorithm in analyze.c
Commit 83e176ec1 moved row sampling functions from analyze.c to
utils/misc/sampling.c, but failed to update comment referring to
the sampling algorithm from Jeff Vitter's paper. Correct the
comment by pointing to utils/misc/sampling.c.

Author: Etsuro Fujita
Discussion: https://postgr.es/m/CAPmGK154gp%2BQd%3DcorQOv%2BPmbyVyZBjp_%2Bhb766UJeD1e_ie6XQ%40mail.gmail.com
2019-06-27 18:01:54 +02:00
Alvaro Herrera 050098b14e Fix use-after-free introduced in 55ed3defc9
Evidenced by failure under RELCACHE_FORCE_RELEASE (buildfarm member
prion).

Author: Amit Langote
Discussion: https://postgr.es/m/CA+HiwqGV=k_Eh4jBiQw66ivvdG+EUkrEYeHTYL1SvDj_YOYV0g@mail.gmail.com
2019-06-27 11:57:10 -04:00
Peter Eisentraut f2f0082ef5 Update comment
Function was renamed/replaced in
c2fe139c20 but the header comment was
not updated.
2019-06-27 15:57:14 +02:00
Alvaro Herrera 55ed3defc9 Fix partitioned index creation with foreign partitions
When a partitioned tables contains foreign tables as partitions, it is
not possible to implement unique or primary key indexes -- but when
regular indexes are created, there is no reason to do anything other
than ignoring such partitions.  We were raising errors upon encountering
the foreign partitions, which is unfriendly and doesn't protect against
any actual problems.

Relax this restriction so that index creation is allowed on partitioned
tables containing foreign partitions, becoming a no-op on them.  (We may
later want to redefine this so that the FDW is told to create the
indexes on the foreign side.)  This applies to CREATE INDEX, as well as
ALTER TABLE / ATTACH PARTITION and CREATE TABLE / PARTITION OF.

Backpatch to 11, where indexes on partitioned tables were introduced.

Discussion: https://postgr.es/m/15724-d5a58fa9472eef4f@postgresql.org
Author: Álvaro Herrera
Reviewed-by: Amit Langote
2019-06-26 18:38:51 -04:00
Michael Paquier ce59b75d44 Add toast-level reloption for vacuum_index_cleanup
a96c41f has introduced the option for heap, but it still lacked the
variant to control the behavior for toast relations.

While on it, refactor the tests so as they stress more scenarios with
the various values that vacuum_index_cleanup can use.  It would be
useful to couple those tests with pageinspect to check that pages are
actually cleaned up, but this is left for later.

Author: Masahiko Sawada, Michael Paquier
Reviewed-by: Peter Geoghegan
Discussion: https://postgr.es/m/CAD21AoCqs8iN04RX=i1KtLSaX5RrTEM04b7NHYps4+rqtpWNEg@mail.gmail.com
2019-06-25 09:09:27 +09:00
Tom Lane ccfcc8fdbd Purely-cosmetic adjustments in tablecmds.c.
Move ATExecAlterColumnGenericOptions away from where it was unthinkingly
dropped, in the middle of a lot of ALTER COLUMN TYPE code.  I don't have
any high principles about where to put it instead, so let's just put it
after ALTER COLUMN TYPE and before ALTER OWNER, matching existing
decisions about how to order related code stanzas.

Also add the minimal function header comment that the original author
was too cool to bother with.

Along the way, upgrade header comments for nearby ALTER COLUMN TYPE
functions.

Discussion: https://postgr.es/m/14787.1561403130@sss.pgh.pa.us
2019-06-24 17:19:37 -04:00
Tom Lane f946a40914 Further fix ALTER COLUMN TYPE's handling of indexes and index constraints.
This patch reverts all the code changes of commit e76de8861, which turns
out to have been seriously misguided.  We can't wait till later to compute
the definition string for an index; we must capture that before applying
the data type change for any column it depends on, else ruleutils.c will
deliverr wrong/misleading results.  (This fine point was documented
nowhere, of course.)

I'd also managed to forget that ATExecAlterColumnType executes once per
ALTER COLUMN TYPE clause, not once per statement; which resulted in the
code being basically completely broken for any case in which multiple ALTER
COLUMN TYPE clauses are applied to a table having non-constraint indexes
that must be rebuilt.  Through very bad luck, none of the existing test
cases nor the ones added by e76de8861 caught that, but of course it was
soon found in the field.

The previous patch also had an implicit assumption that if a constraint's
index had a dependency on a table column, so would the constraint --- but
that isn't actually true, so it didn't fix such cases.

Instead of trying to delete unneeded index dependencies later, do the
is-there-a-constraint lookup immediately on seeing an index dependency,
and switch to remembering the constraint if so.  In the unusual case of
multiple column dependencies for a constraint index, this will result in
duplicate constraint lookups, but that's not that horrible compared to all
the other work that happens here.  Besides, such cases did not work at all
before, so it's hard to argue that they're performance-critical for anyone.

Per bug #15865 from Keith Fiske.  As before, back-patch to all supported
branches.

Discussion: https://postgr.es/m/15865-17940eacc8f8b081@postgresql.org
2019-06-24 16:43:21 -04:00
Peter Eisentraut 12e037e209 Upgrade internal error message to external
As part of REINDEX CONCURRENTLY, this formerly internal-only error
message becomes potentially user-visible (see regression tests), so
change from errmsg_internal() to errmsg(), and update comment.
2019-06-24 10:39:12 +02:00
Noah Misch 9a81c9fa3f Don't call PG_RETURN_BOOL() in a function not returning Datum.
This code is new in v12, and the defect probably was not user-visible.
2019-06-23 12:02:19 -07:00
Dean Rasheed d7f8d26d9f Add security checks to the multivariate MCV estimation code.
The multivariate MCV estimation code may run user-defined operators on
the values in the MCV list, which means that those operators may
potentially leak the values from the MCV list. Guard against leaking
data to unprivileged users by checking that the user has SELECT
privileges on the table or all of the columns referred to by the
statistics.

Additionally, if there are any securityQuals on the RTE (either due to
RLS policies on the table, or accessing the table via a security
barrier view), not all rows may be visible to the current user, even
if they have table or column privileges. Thus we further insist that
the operator be leakproof in this case.

Dean Rasheed, reviewed by Tomas Vondra.

Discussion: https://postgr.es/m/CAEZATCUhT9rt7Ui=Vdx4N==VV5XOK5dsXfnGgVOz_JhAicB=ZA@mail.gmail.com
2019-06-23 18:50:08 +01:00
Thomas Munro 89ff7c08ee Remove unnecessary comment.
Author: Vik Fearing
Discussion: https://postgr.es/m/150d3e9f-c7ec-3fb3-4fdb-def47c4144af%402ndquadrant.com
2019-06-23 22:19:59 +12:00
Thomas Munro 25b93a2967 Remove obsolete comments about sempahores from proc.c.
Commit 6753333f switched from a semaphore-based wait to a latch-based
wait for ProcSleep()/ProcWakeup(), but left behind some stray references
to semaphores.

Back-patch to 9.5.

Reviewed-by: Daniel Gustafsson, Michael Paquier
Discussion: https://postgr.es/m/CA+hUKGLs5H6zhmgTijZ1OaJvC1sG0=AFXc1aHuce32tKiQrdEA@mail.gmail.com
2019-06-21 10:57:07 +12:00
Michael Paquier 20e1cc898d Rework some error strings for REINDEX CONCURRENTLY with system catalogs
This makes the whole user experience more consistent when bumping into
failures, and more in line with the rewording done via 508300e.

Author: Michael Paquier
Reviewed-by: Álvaro Herrera
Discussion: https://postgr.es/m/20190514153252.GA22168@alvherre.pgsql
2019-06-20 13:28:12 +09:00
Alexander Korotkov 261a5c1928 Support 'q' flag in jsonpath 'like_regex' predicate
SQL/JSON standard defines that jsonpath 'like_regex' predicate should support
the same set of flags as XQuery/XPath.  It appears that implementation of 'q'
flag was missed.  This commit fixes that.

Discussion: https://postgr.es/m/CAPpHfdtyfPsxLYiTjp5Ov8T5xGsB5t3CwE5%2B3PS%3DLLwA%2BxTJog%40mail.gmail.com
Author: Nikita Glukhov, Alexander Korotkov
2019-06-19 22:41:57 +03:00
Peter Eisentraut d8594d123c Update list of combining characters
The list of combining characters to ignore for calculating the display
width of a string (used for example by psql) was wildly outdated and
incorrect.

Discussion: https://www.postgresql.org/message-id/flat/bbb19114-af1e-513b-08a9-61272794bd5c%402ndquadrant.com
2019-06-19 21:35:41 +02:00
Magnus Hagander 66013fe730 Fix typo
Author: Daniel Gustafsson
2019-06-19 14:59:26 +02:00
Michael Paquier 3c28fd2281 Fix description of WAL record XLOG_BTREE_META_CLEANUP
This record uses one metadata buffer and registers some data associated
to the buffer, but when parsing the record for its description a direct
access to the record data was done, but there is none.  This leads
usually to an incorrect description, but can also cause crashes like in
pg_waldump.  Instead, fix things so as the parsing uses the data
associated to the metadata block.

This is an oversight from 3d92796, so backpatch down to 11.

Author: Michael Paquier
Description: https://postgr.es/m/20190617013059.GA3153@paquier.xyz
Backpatch-through: 11
2019-06-19 11:02:19 +09:00
Andres Freund 23224563d9 Fix memory corruption/crash in ANALYZE.
This fixes an embarrassing oversight I (Andres) made in 737a292b,
namely missing two place where liverows/deadrows were used when
converting those variables to pointers, leading to incrementing the
pointer, rather than the value.

It's not that actually that easy to trigger a crash: One needs tuples
deleted by the current transaction, followed by a tuple deleted in
another session, all in one page. Which is presumably why this hasn't
been noticed before.

Reported-By: Steve Singer
Author: Steve Singer
Discussion: https://postgr.es/m/c7988239-d42c-ddc4-41db-171b23b35e4f@ssinger.info
2019-06-18 15:51:04 -07:00
Alvaro Herrera 8b21b416ed Avoid spurious deadlocks when upgrading a tuple lock
This puts back reverted commit de87a084c0, with some bug fixes.

When two (or more) transactions are waiting for transaction T1 to release a
tuple-level lock, and transaction T1 upgrades its lock to a higher level, a
spurious deadlock can be reported among the waiting transactions when T1
finishes.  The simplest example case seems to be:

T1: select id from job where name = 'a' for key share;
Y: select id from job where name = 'a' for update; -- starts waiting for T1
Z: select id from job where name = 'a' for key share;
T1: update job set name = 'b' where id = 1;
Z: update job set name = 'c' where id = 1; -- starts waiting for T1
T1: rollback;

At this point, transaction Y is rolled back on account of a deadlock: Y
holds the heavyweight tuple lock and is waiting for the Xmax to be released,
while Z holds part of the multixact and tries to acquire the heavyweight
lock (per protocol) and goes to sleep; once T1 releases its part of the
multixact, Z is awakened only to be put back to sleep on the heavyweight
lock that Y is holding while sleeping.  Kaboom.

This can be avoided by having Z skip the heavyweight lock acquisition.  As
far as I can see, the biggest downside is that if there are multiple Z
transactions, the order in which they resume after T1 finishes is not
guaranteed.

Backpatch to 9.6.  The patch applies cleanly on 9.5, but the new tests don't
work there (because isolationtester is not smart enough), so I'm not going
to risk it.

Author: Oleksii Kliukin
Discussion: https://postgr.es/m/B9C9D7CD-EB94-4635-91B6-E558ACEC0EC3@hintbits.com
Discussion: https://postgr.es/m/2815.1560521451@sss.pgh.pa.us
2019-06-18 18:23:16 -04:00
Thomas Munro aca127c105 Prevent Parallel Hash Join for JOIN_UNIQUE_INNER.
WHERE EXISTS (...) queries cannot be executed by Parallel Hash Join
with jointype JOIN_UNIQUE_INNER, because there is no way to make a
partial plan totally unique.  The consequence of allowing such plans
was duplicate results from some EXISTS queries.

Back-patch to 11.  Bug #15857.

Author: Thomas Munro
Reviewed-by: Tom Lane
Reported-by: Vladimir Kriukov
Discussion: https://postgr.es/m/15857-d1ba2a64bce0795e%40postgresql.org
2019-06-19 01:25:57 +12:00
Peter Eisentraut 91acff7a53 Translation updates
Source-Git-URL: https://git.postgresql.org/git/pgtranslation/messages.git
Source-Git-Hash: 1a710c413ce4c4cd081843e563cde256bb95f490
2019-06-17 15:30:20 +02:00
Michael Paquier 09ec55b933 Fix buffer overflow when parsing SCRAM verifiers in backend
Any authenticated user can overflow a stack-based buffer by changing the
user's own password to a purpose-crafted value.  This often suffices to
execute arbitrary code as the PostgreSQL operating system account.

This fix is contributed by multiple folks, based on an initial analysis
from Tom Lane.  This issue has been introduced by 68e61ee, so it was
possible to make use of it at authentication time.  It became more
easily to trigger after ccae190 which has made the SCRAM parsing more
strict when changing a password, in the case where the client passes
down a verifier already hashed using SCRAM.  Back-patch to v10 where
SCRAM has been introduced.

Reported-by: Alexander Lakhin
Author: Jonathan Katz, Heikki Linnakangas, Michael Paquier
Security: CVE-2019-10164
Backpatch-through: 10
2019-06-17 21:48:17 +09:00
Michael Paquier 3412030205 Fix more typos and inconsistencies in the tree
Author: Alexander Lakhin
Discussion: https://postgr.es/m/0a5419ea-1452-a4e6-72ff-545b1a5a8076@gmail.com
2019-06-17 16:13:16 +09:00
Alvaro Herrera 9d20b0ec8f Revert "Avoid spurious deadlocks when upgrading a tuple lock"
This reverts commits 3da73d6839 and de87a084c0.

This code has some tricky corner cases that I'm not sure are correct and
not properly tested anyway, so I'm reverting the whole thing for next
week's releases (reintroducing the deadlock bug that we set to fix).
I'll try again afterwards.

Discussion: https://postgr.es/m/E1hbXKQ-0003g1-0C@gemulon.postgresql.org
2019-06-16 22:24:21 -04:00
Tom Lane 6973b058bc Further fix privileges on pg_statistic_ext[_data].
We don't need to restrict column privileges on pg_statistic_ext;
all of that data is OK to read publicly.  What we *do* need to do,
which was overlooked by 6cbfb784c, is revoke public read access on
pg_statistic_ext_data; otherwise we still have the same security
hole we started with.

Catversion bump to ensure that installations calling themselves
beta2 will have this fix.

Diagnosis/correction by Dean Rasheed and Tomas Vondra, but I'm
going to go ahead and push this fix ASAP so we get more buildfarm
cycles on it.

Discussion: https://postgr.es/m/8833.1560647898@sss.pgh.pa.us
2019-06-16 11:00:23 -04:00
Tomas Vondra fc8cf3df47 Fix privileges on pg_statistic_ext.tableoid
The GRANT in system_views allowed SELECT privileges on various columns in
the pg_statistic_ext catalog, but tableoid was not included in the list.
That made pg_dump fail because it's accessing this column when building
the list of extended statistics to dump.

Discussion: https://postgr.es/m/8833.1560647898%40sss.pgh.pa.us
2019-06-16 12:12:16 +02:00
Tomas Vondra aa087ec64f Add pg_stats_ext view for extended statistics
Regular per-column statistics are stored in pg_statistics catalog, which
is however rather difficult to read, so we also have pg_stats view with
a human-reablable version of the data.

For extended statistic the catalog was fairly easy to read, so we did
not have such human-readable view so far.  Commit 9b6babfa2d however did
split the catalog into two, which makes querying harder.  Furthermore,
we want to show the multi-column MCV list in a way similar to per-column
stats (and not as a bytea value).

This commit introduces pg_stats_ext view, joining the two catalogs and
massaging the data to produce human-readable output similar to pg_stats.
It also considers RLS and access privileges - the data is shown only when
the user has access to all columns the extended statistic is defined on.

Bumped CATVERSION due to adding new system view.

Author: Dean Rasheed, with improvements by me
Reviewed-by: Dean Rasheed, John Naylor
Discussion: https://postgr.es/m/CAEZATCUhT9rt7Ui%3DVdx4N%3D%3DVV5XOK5dsXfnGgVOz_JhAicB%3DZA%40mail.gmail.com
2019-06-16 01:20:39 +02:00
Tomas Vondra 6cbfb784c3 Rework the pg_statistic_ext catalog
Since extended statistic got introduced in PostgreSQL 10, there was a
single catalog pg_statistic_ext storing both the definitions and built
statistic.  That's however problematic when a user is supposed to have
access only to the definitions, but not to user data.

Consider for example pg_dump on a database with RLS enabled - if the
pg_statistic_ext catalog respects RLS (which it should, if it contains
user data), pg_dump would not see any records and the result would not
define any extended statistics.  That would be a surprising behavior.

Until now this was not a pressing issue, because the existing types of
extended statistic (functional dependencies and ndistinct coefficients)
do not include any user data directly.  This changed with introduction
of MCV lists, which do include most common combinations of values.

The easiest way to fix this is to split the pg_statistic_ext catalog
into two - one for definitions, one for the built statistic values.
The new catalog is called pg_statistic_ext_data, and we're maintaining
a 1:1 relationship with the old catalog - either there are matching
records in both catalogs, or neither of them.

Bumped CATVERSION due to changing system catalog definitions.

Author: Dean Rasheed, with improvements by me
Reviewed-by: Dean Rasheed, John Naylor
Discussion: https://postgr.es/m/CAEZATCUhT9rt7Ui%3DVdx4N%3D%3DVV5XOK5dsXfnGgVOz_JhAicB%3DZA%40mail.gmail.com
2019-06-16 01:20:31 +02:00
Alvaro Herrera 3da73d6839 Silence compiler warning
Introduced in de87a084c0.
2019-06-14 11:33:40 -04:00
Michael Paquier f43608bda2 Fix typos and inconsistencies in code comments
Author: Alexander Lakhin
Discussion: https://postgr.es/m/dec6aae8-2d63-639f-4d50-20e229fb83e3@gmail.com
2019-06-14 09:34:34 +09:00
Tom Lane d25ea01275 Avoid combinatorial explosion in add_child_rel_equivalences().
If an EquivalenceClass member expression includes variables from
multiple appendrels, then instead of producing one substituted
expression per child relation as intended, we'd create additional
child expressions for combinations of children of different appendrels.
This happened because the child expressions generated while considering
the first appendrel were taken as sources during substitution of the
second appendrel, and so on.  The extra expressions are useless, and are
harmless unless there are too many of them --- but if you have several
appendrels with a thousand or so members each, it gets bad fast.

To fix, consider only original (non-em_is_child) EC members as candidates
to be expanded.  This requires the ability to substitute directly from a
top parent relation's Vars to those of an indirect descendant relation,
but we already have that in adjust_appendrel_attrs_multilevel().

Per bug #15847 from Feike Steenbergen.  This is a longstanding misbehavior,
but it's only worth worrying about when there are more appendrel children
than we've historically considered wise to use.  So I'm not going to take
the risk of back-patching this.

Discussion: https://postgr.es/m/15847-ea3734094bf8ae61@postgresql.org
2019-06-13 18:10:20 -04:00
Alvaro Herrera de87a084c0 Avoid spurious deadlocks when upgrading a tuple lock
When two (or more) transactions are waiting for transaction T1 to release a
tuple-level lock, and transaction T1 upgrades its lock to a higher level, a
spurious deadlock can be reported among the waiting transactions when T1
finishes.  The simplest example case seems to be:

T1: select id from job where name = 'a' for key share;
Y: select id from job where name = 'a' for update; -- starts waiting for X
Z: select id from job where name = 'a' for key share;
T1: update job set name = 'b' where id = 1;
Z: update job set name = 'c' where id = 1; -- starts waiting for X
T1: rollback;

At this point, transaction Y is rolled back on account of a deadlock: Y
holds the heavyweight tuple lock and is waiting for the Xmax to be released,
while Z holds part of the multixact and tries to acquire the heavyweight
lock (per protocol) and goes to sleep; once X releases its part of the
multixact, Z is awakened only to be put back to sleep on the heavyweight
lock that Y is holding while sleeping.  Kaboom.

This can be avoided by having Z skip the heavyweight lock acquisition.  As
far as I can see, the biggest downside is that if there are multiple Z
transactions, the order in which they resume after X finishes is not
guaranteed.

Backpatch to 9.6.  The patch applies cleanly on 9.5, but the new tests don't
work there (because isolationtester is not smart enough), so I'm not going
to risk it.

Author: Oleksii Kliukin
Discussion: https://postgr.es/m/B9C9D7CD-EB94-4635-91B6-E558ACEC0EC3@hintbits.com
2019-06-13 17:28:24 -04:00
Tom Lane 3d99a81397 Fix incorrect printing of queries with duplicated join names.
Given a query in which multiple JOIN nodes used the same alias
(which'd necessarily be in different sub-SELECTs), ruleutils.c
would assign the JOIN nodes distinct aliases for clarity ...
but then it forgot to print the modified aliases when dumping
the JOIN nodes themselves.  This results in a dump/reload hazard
for views, because the emitted query is flat-out incorrect:
Vars will be printed with table names that have no referent.

This has been wrong for a long time, so back-patch to all supported
branches.

Philip Dubé

Discussion: https://postgr.es/m/CY4PR2101MB080246F2955FF58A6ED1FEAC98140@CY4PR2101MB0802.namprd21.prod.outlook.com
2019-06-12 19:43:08 -04:00
Tom Lane e76de88615 Fix ALTER COLUMN TYPE failure with a partial exclusion constraint.
ATExecAlterColumnType failed to consider the possibility that an index
that needs to be rebuilt might be a child of a constraint that needs to be
rebuilt.  We missed this so far because usually a constraint index doesn't
have a direct dependency on its table, just on the constraint object.
But if there's a WHERE clause, then dependency analysis of the WHERE
clause results in direct dependencies on the column(s) mentioned in WHERE.
This led to trying to drop and rebuild both the constraint and its
underlying index.

In v11/HEAD, we successfully drop both the index and the constraint,
and then try to rebuild both, and of course the second rebuild hits a
duplicate-index-name problem.  Before v11, it fails with obscure messages
about a missing relation OID, due to trying to drop the index twice.

This is essentially the same kind of problem noted in commit
20bef2c31: the possible dependency linkages are broader than what
ATExecAlterColumnType was designed for.  It was probably OK when
written, but it's certainly been broken since the introduction of
partial exclusion constraints.  Fix by adding an explicit check
for whether any of the indexes-to-be-rebuilt belong to any of the
constraints-to-be-rebuilt, and ignoring any that do.

In passing, fix a latent bug introduced by commit 8b08f7d48: in
get_constraint_index() we must "continue" not "break" when rejecting
a relation of a wrong relkind.  This is harmless today because we don't
expect that code path to be taken anyway; but if there ever were any
relations to be ignored, the existing coding would have an extremely
undesirable dependency on the order of pg_depend entries.

Also adjust a couple of obsolete comments.

Per bug #15835 from Yaroslav Schekin.  Back-patch to all supported
branches.

Discussion: https://postgr.es/m/15835-32d9b7a76c06a7a9@postgresql.org
2019-06-12 12:29:39 -04:00
Michael Paquier ceac4505d3 Fix handling of COMMENT for domain constraints
For a non-superuser, changing a comment on a domain constraint was
leading to a cache lookup failure as the code tried to perform the
ownership lookup on the constraint OID itself, thinking that it was a
type, but this check needs to happen on the type the domain constraint
relies on.  As the type a domain constraint relies on can be guessed
directly based on the constraint OID, first fetch its type OID and
perform the ownership on it.

This is broken since 7eca575, which has split the handling of comments
for table constraints and domain constraints, so back-patch down to
9.5.

Reported-by: Clemens Ladisch
Author: Daniel Gustafsson, Michael Paquier
Reviewed-by: Álvaro Herrera
Discussion: https://postgr.es/m/15833-808e11904835d26f@postgresql.org
Backpatch-through: 9.5
2019-06-12 11:30:11 +09:00
Tom Lane 6f34fcbbd5 Fix conversion of JSON strings to JSON output columns in json_to_record().
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
2019-06-11 13:33:22 -04:00
Andres Freund fff2a7d7bd Don't access catalogs to validate GUCs when not connected to a DB.
Vignesh found this bug in the check function for
default_table_access_method's check hook, but that was just copied
from older GUCs. Investigation by Michael and me then found the bug in
further places.

When not connected to a database (e.g. in a walsender connection), we
cannot perform (most) GUC checks that need database access. Even when
only shared tables are needed, unless they're
nailed (c.f. RelationCacheInitializePhase2()), they cannot be accessed
without pg_class etc. being present.

Fix by extending the existing IsTransactionState() checks to also
check for MyDatabaseOid.

Reported-By: Vignesh C, Michael Paquier, Andres Freund
Author: Vignesh C, Andres Freund
Discussion: https://postgr.es/m/CALDaNm1KXK9gbZfY-p_peRFm_XrBh1OwQO1Kk6Gig0c0fVZ2uw%40mail.gmail.com
Backpatch: 9.4-
2019-06-10 23:34:50 -07:00
Noah Misch 44982e7d09 Reconcile nodes/*funcs.c with PostgreSQL 12 work.
One would have needed out-of-tree code to observe the defects.  Remove
unreferenced fields instead of completing their support functions.
Since in-tree code can't reach _readIntoClause(), no catversion bump.
2019-06-09 14:00:36 -07:00
Noah Misch 31d250e049 Update stale comments, and fix comment typos. 2019-06-08 10:12:26 -07:00
Amit Kapila 92c4abc736 Fix assorted inconsistencies.
There were a number of issues in the recent commits which include typos,
code and comments mismatch, leftover function declarations.  Fix them.

Reported-by: Alexander Lakhin
Author: Alexander Lakhin, Amit Kapila and Amit Langote
Reviewed-by: Amit Kapila
Discussion: https://postgr.es/m/ef0c0232-0c1d-3a35-63d4-0ebd06e31387@gmail.com
2019-06-08 08:16:38 +05:30