[pgpool-general: 8259] Re: Shared memory cache size formula
ishii at sraoss.co.jp
Mon Jun 27 14:27:25 JST 2022
> Do you know what is the best formula to calculate the cache size when using
> shared memory, in case I want a greater query result size.
> How do I address to the block size and the number of cache entries?
Unless your queries return very large results, usually you don't need
to adjust the cache block size.
For the number of cache entries (num_hash_entries), you should consult
"show pool_cache" command. Here are some advices:
- If cache_hit_ration is good enough (for example over 0.9), then you
do not need to adjst num_hash_entries.
- If cache_hit_ration is not good, try to increase num_hash_entries so
that pgpool can hold more cache entries. However, it is possible
that the cache hit ratio won't be better because your system is
write heavy. In this case you should think more if you really want
to use the cache system.
SRA OSS, Inc. Japan
More information about the pgpool-general