Hi Horiguchi-san, Bruce, From: Bruce Momjian [mailto:br...@momjian.us] > I suggest you go with just syscache_prune_min_age, get that into PG 12, > and we can then reevaluate what we need. If you want to hard-code a > minimum cache size where no pruning will happen, maybe based on the system > catalogs or typical load, that is fine.
Please forgive me if I say something silly (I might have got lost.) Are you suggesting to make the cache size limit system-defined and uncontrollable by the user? I think it's necessary for the DBA to be able to control the cache memory amount. Otherwise, if many concurrent connections access many partitions within a not-so-long duration, then the cache eviction can't catch up and ends up in OOM. How about the following questions I asked in my previous mail? -------------------------------------------------- This is a pure question. How can we answer these questions from users? * What value can I set to cache_memory_target when I can use 10 GB for the caches and max_connections = 100? * How much RAM do I need to have for the caches when I set cache_memory_target = 1M? The user tends to estimate memory to avoid OOM. -------------------------------------------------- Regards Takayuki Tsunakawa
