Re: larger shared buffers slows down cluster

Andrew Dunstan <andrew@dunslane.net> writes:
> Now running:
>     cluster bar using bar_abcde;
> appears to be very sensitive to the shared buffers setting. In an amazon 
> very large memory instance (64GB) and PostgreSQL 9.1.4, I observed the 
> following timings:

>      Shared Buffers   Time
>        48Gb           2058ms
>         8Gb            372ms
>         1gb             67ms

DropRelFileNodeBuffers, perhaps?  See recent commits to reduce the cost
of that for large shared_buffers, notably
e8d029a30b5a5fb74b848a8697b1dfa3f66d9697 and
ece01aae479227d9836294b287d872c5a6146a11
        regards, tom lane