Log Message:
-----------
Avoid having autovacuum read pgstats data too many times in quick succession.
This is problematic for the autovac launcher when there are many databases,
so we keep data for a full second before reading it again.
Modified Files:
--------------
pgsql/src/backend/postmaster:
autovacuum.c (r1.60 -> r1.61)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/postmaster/autovacuum.c?r1=1.60&r2=1.61)