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Tom Lane f912d7dec2 Fix reindexing of pg_class indexes some more.
Commits 3dbb317d3 et al failed under CLOBBER_CACHE_ALWAYS testing.
Investigation showed that to reindex pg_class_oid_index, we must
suppress accesses to the index (via SetReindexProcessing) before we call
RelationSetNewRelfilenode, or at least before we do CommandCounterIncrement
therein; otherwise, relcache reloads happening within the CCI may try to
fetch pg_class rows using the index's new relfilenode value, which is as
yet an empty file.

Of course, the point of 3dbb317d3 was that that ordering didn't work
either, because then RelationSetNewRelfilenode's own update of the index's
pg_class row cannot access the index, should it need to.

There are various ways we might have got around that, but Andres Freund
came up with a brilliant solution: for a mapped index, we can really just
skip the pg_class update altogether.  The only fields it was actually
changing were relpages etc, but it was just setting them to zeroes which
is useless make-work.  (Correct new values will be installed at the end
of index build.)  All pg_class indexes are mapped and probably always will
be, so this eliminates the problem by removing work rather than adding it,
always a pleasant outcome.  Having taught RelationSetNewRelfilenode to do
it that way, we can revert the code reordering in reindex_index.  (But
I left the moved setup code where it was; there seems no reason why it
has to run without use of the old index.  If you're trying to fix a
busted pg_class index, you'll have had to disable system index use
altogether to get this far.)

Moreover, this means we don't need RelationSetIndexList at all, because
reindex_relation's hacking to make "REINDEX TABLE pg_class" work is
likewise now unnecessary.  We'll leave that code in place in the back
branches, but a follow-on patch will remove it in HEAD.

In passing, do some minor cleanup for commit 5c1560606 (in HEAD only),
notably removing a duplicate newrnode assignment.

Patch by me, using a core idea due to Andres Freund.  Back-patch to all
supported branches, as 3dbb317d3 was.

Discussion: https://postgr.es/m/28926.1556664156@sss.pgh.pa.us
2019-05-02 19:11:28 -04:00
config Update config.guess and config.sub 2019-04-27 14:25:00 +02:00
contrib Fix potential assertion failure when reindexing a pg_class index. 2019-04-29 19:42:08 -07:00
doc doc: clarify behavior of pg_upgrade's clone mode 2019-05-01 09:09:28 -04:00
src Fix reindexing of pg_class indexes some more. 2019-05-02 19:11:28 -04:00
.dir-locals.el Make Emacs perl-mode indent more like perltidy. 2019-01-13 11:32:31 -08:00
.gitattributes doc: Add some images 2019-03-27 23:10:23 +01:00
.gitignore Support for optimizing and emitting code in LLVM JIT provider. 2018-03-22 11:05:22 -07:00
COPYRIGHT Update copyright for 2019 2019-01-02 12:44:25 -05:00
GNUmakefile.in Process EXTRA_INSTALL serially, during the first temp-install. 2018-12-31 13:54:38 -08:00
HISTORY Change documentation references to PG website to use https: not http: 2017-05-20 21:50:47 -04:00
Makefile Fix non-GNU makefiles for AIX make. 2017-11-30 00:57:22 -08:00
README Change documentation references to PG website to use https: not http: 2017-05-20 21:50:47 -04:00
README.git Change documentation references to PG website to use https: not http: 2017-05-20 21:50:47 -04:00
aclocal.m4 Fix configure's AC_CHECK_DECLS tests to work correctly with clang. 2018-11-19 12:01:47 -05:00
configure Reorder configure tests for accept() in Windows 2019-03-04 14:42:12 -05:00
configure.in Fix PERMIT_DECLARATION_AFTER_STATEMENT initialization. 2019-02-16 13:12:28 -08:00

README

PostgreSQL Database Management System
=====================================

This directory contains the source code distribution of the PostgreSQL
database management system.

PostgreSQL is an advanced object-relational database management system
that supports an extended subset of the SQL standard, including
transactions, foreign keys, subqueries, triggers, user-defined types
and functions.  This distribution also contains C language bindings.

PostgreSQL has many language interfaces, many of which are listed here:

	https://www.postgresql.org/download

See the file INSTALL for instructions on how to build and install
PostgreSQL.  That file also lists supported operating systems and
hardware platforms and contains information regarding any other
software packages that are required to build or run the PostgreSQL
system.  Copyright and license information can be found in the
file COPYRIGHT.  A comprehensive documentation set is included in this
distribution; it can be read as described in the installation
instructions.

The latest version of this software may be obtained at
https://www.postgresql.org/download/.  For more information look at our
web site located at https://www.postgresql.org/.