> > On Oct 15, 2018, at 12:04 PM, Ghiurea, Isabella <Isabella.Ghiurea@xxxxxxxxxxxxxx> wrote: > > I am running PGSQL 10.4 on Cent OS Pg instance has ' effective_cache_size' parameter not enabled I would like to learn what will the optimizer behavior be in this case ? > ( default is set to 4GB , I was thinking PG 's optimizer will try to use all available OS RAM when trying to estimate a query, is this the case) That's merely a hint to the optimizer as to how much file data is likely to be cached by the OS--it doesn't directly affect any PG allocations, rather it might influence PG's choice of steps to carry out a query, which of course could indirectly change the RAM that PG would use. -- Scott Ribe scott_ribe@xxxxxxxxxxxxxxxx https://www.linkedin.com/in/scottribe/
