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postgres/src/backend
Tom Lane 3c96f5c647 Fix unsafe order of operations in foreign-table DDL commands.
When updating or deleting a system catalog tuple, it's necessary to acquire
RowExclusiveLock on the catalog before looking up the tuple; otherwise a
concurrent VACUUM FULL on the catalog might move the tuple to a different
TID before we can apply the update.  Coding patterns that find the tuple
via a table scan aren't at risk here, but when obtaining the tuple from a
catalog cache, correct ordering is important; and several routines in
foreigncmds.c got it wrong.  Noted while running the regression tests in
parallel with VACUUM FULL of assorted system catalogs.

For consistency I moved all the heap_open calls to the starts of their
functions, including a couple for which there was no actual bug.

Back-patch to 8.4 where foreigncmds.c was added.
2011-08-14 15:40:41 -04:00
..
2009-01-01 17:24:05 +00:00
2009-01-01 17:24:05 +00:00
2010-09-30 23:31:19 +03:00