pgsql: Fix relfilenodemap.c's handling of cache invalidations.

Fix relfilenodemap.c's handling of cache invalidations.

The old code entered a new hash table entry first, then scanned
pg_class to determine what value to fill in, and then populated the
entry. This fails to work properly if a cache invalidation happens
as a result of opening pg_class. Repair.

Along the way, get rid of the idea of blowing away the entire hash
table as a method of processing invalidations. Instead, just delete
all the entries one by one. This is probably not quite as cheap but
it's simpler, and shouldn't happen often.

Andres Freund

Branch
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master

Details
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http://git.postgresql.org/pg/commitdiff/c46c803f8ad4ba80472b280703983ecf8021099e

Modified Files
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src/backend/utils/cache/relfilenodemap.c | 189 ++++++++++++++++--------------
1 file changed, 100 insertions(+), 89 deletions(-)