On 2014-04-28 10:57:12 -0400, Tom Lane wrote: > Andres Freund <and...@2ndquadrant.com> writes: > > On 2014-04-28 10:03:58 -0400, Tom Lane wrote: > >> What I find much more worrisome about Andres' proposals is that he > >> seems to be thinking that there are *no* other changes to the buffer > >> headers on the horizon. > > > Err. I am not thinking that at all. I am pretty sure I never made that > > argument. The reason I want to limit the number of connections is it > > allows *both*, shrinking the size of BufferDescs due to less alignment > > padding *and* stuffing the refcount and flags into one integer. > > Weren't you saying you also wanted to stuff the usage count into that same > integer? That's getting a little too tight for my taste, even if it would > fit today.
That's a possible additional optimization that we could use. But it's certainly not required. Would allow us to use fewer atomic operations... Right now there'd be enough space for a more precise usagecount and more flags. ATM there's 9 bits for flags and 3 bits of usagecount... Greetings, Andres Freund -- Andres Freund http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Training & Services -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
