Thread: pgsql: Remove the limit on the number of entries allowed in catcaches,
pgsql: Remove the limit on the number of entries allowed in catcaches,
From
tgl@postgresql.org (Tom Lane)
Date:
Log Message: ----------- Remove the limit on the number of entries allowed in catcaches, and remove the infrastructure needed to enforce the limit, ie, the global LRU list of cache entries. On small-to-middling databases this wins because maintaining the LRU list is a waste of time. On large databases this wins because it's better to keep more cache entries (we assume such users can afford to use some more per-backend memory than was contemplated in the Berkeley-era catcache design). This provides a noticeable improvement in the speed of psql \d on a 10000-table database, though it doesn't make it instantaneous. While at it, use per-catcache settings for the number of hash buckets per catcache, rather than the former one-size-fits-all value. It's a bit silly to be using the same number of hash buckets for, eg, pg_am and pg_attribute. The specific values I used might need some tuning, but they seem to be in the right ballpark based on CATCACHE_STATS results from the standard regression tests. Modified Files: -------------- pgsql/src/backend/utils/cache: catcache.c (r1.128 -> r1.129) (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/utils/cache/catcache.c.diff?r1=1.128&r2=1.129) syscache.c (r1.103 -> r1.104) (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/utils/cache/syscache.c.diff?r1=1.103&r2=1.104) pgsql/src/include/utils: catcache.h (r1.58 -> r1.59) (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/include/utils/catcache.h.diff?r1=1.58&r2=1.59)