postgresql/src
Tom Lane 10564ee02c Fix code for re-finding scan position in a multicolumn GIN index.
collectMatchBitmap() needs to re-find the index tuple it was previously
looking at, after transiently dropping lock on the index page it's on.
The tuple should still exist and be at its prior position or somewhere
to the right of that, since ginvacuum never removes tuples but
concurrent insertions could add one.  However, there was a thinko in
that logic, to the effect of expecting any inserted tuples to have the
same index "attnum" as what we'd been scanning.  Since there's no
physical separation of tuples with different attnums, it's not terribly
hard to devise scenarios where this fails, leading to transient "lost
saved point in index" errors.  (While I've duplicated this with manual
testing, it seems impossible to make a reproducible test case with our
available testing technology.)

Fix by just continuing the scan when the attnum doesn't match.

While here, improve the error message used if we do fail, so that it
matches the wording used in btree for a similar case.

collectMatchBitmap()'s posting-tree code path was previously not
exercised at all by our regression tests.  While I can't make
a regression test that exhibits the bug, I can at least improve
the code coverage here, so do that.  The test case I made for this
is an extension of one added by 4b754d6c1, so it only works in
HEAD and v13; didn't seem worth trying hard to back-patch it.

Per bug #16595 from Jesse Kinkead.  This has been broken since
multicolumn capability was added to GIN (commit 27cb66fdf),
so back-patch to all supported branches.

Discussion: https://postgr.es/m/16595-633118be8eef9ce2@postgresql.org
2020-08-27 17:36:13 -04:00
..
backend Fix code for re-finding scan position in a multicolumn GIN index. 2020-08-27 17:36:13 -04:00
bin Avoid non-constant format string argument to fprintf(). 2020-08-18 13:13:09 +03:00
common Replace remaining StrNCpy() by strlcpy() 2020-08-10 23:20:37 +02:00
fe_utils Move connect.h from fe_utils to src/include/common. 2020-08-10 09:22:54 -07:00
include Add additional information in the vacuum error context. 2020-08-26 09:40:52 +05:30
interfaces Replace remaining StrNCpy() by strlcpy() 2020-08-10 23:20:37 +02:00
makefiles Remove libpq.rc, use win32ver.rc for libpq 2020-01-15 15:06:12 +01:00
pl Fix -Wcast-function-type warnings 2020-07-14 19:55:25 +02:00
port Remove optimization for RAND_poll() failing. 2020-07-25 14:50:59 -07:00
template Fix compiler warning for ppoll() on Cygwin 2019-12-22 23:20:00 +01:00
test Fix code for re-finding scan position in a multicolumn GIN index. 2020-08-27 17:36:13 -04:00
timezone Ensure that distributed timezone abbreviation files are plain ASCII. 2020-07-17 11:03:55 -04:00
tools snapshot scalability: Move subxact info to ProcGlobal, remove PGXACT. 2020-08-14 15:33:35 -07:00
tutorial Update copyrights for 2020 2020-01-01 12:21:45 -05:00
.gitignore Convert cvsignore to gitignore, and add .gitignore for build targets. 2010-09-22 12:57:04 +02:00
DEVELOPERS
Makefile Fix partial-build problems introduced by having more generated headers. 2018-04-09 16:42:10 -04:00
Makefile.global.in Update Unicode data to Unicode 13.0.0 and CLDR 37 2020-04-24 09:52:59 +02:00
Makefile.shlib Add PostgreSQL home page to --help output 2020-02-28 13:12:21 +01:00
nls-global.mk NLS: Fix backend gettext triggers 2019-09-23 09:04:20 +02:00