| From: | Bruce Momjian <bruce(at)momjian(dot)us> |
|---|---|
| To: | Amit Langote <amitlangote09(at)gmail(dot)com> |
| Cc: | Simon Riggs <simon(at)2ndquadrant(dot)com>, Robert Haas <robertmhaas(at)gmail(dot)com>, Josh Berkus <josh(at)agliodbs(dot)com>, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, Magnus Hagander <magnus(at)hagander(dot)net>, Andrew Dunstan <andrew(at)dunslane(dot)net>, Claudio Freire <klaussfreire(at)gmail(dot)com>, Merlin Moncure <mmoncure(at)gmail(dot)com>, PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | Re: proposal: Set effective_cache_size to greater of .conf value, shared_buffers |
| Date: | 2014-05-15 16:35:59 |
| Message-ID: | 20140515163559.GC25053@momjian.us |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-hackers |
On Thu, May 15, 2014 at 11:36:51PM +0900, Amit Langote wrote:
> > No, all memory allocat is per-process, except for shared memory. We
> > probably need a way to record our large local memory allocations in
> > PGPROC that other backends can see; same for effective cache size
> > assumptions we make.
> >
>
> I see. I thought there would be some centralised way to traverse, say,
> a linked list of contexts that individual backends create or something
> like that. But, I suppose it would not be straightforward to make any
> of that work for what we are after here.
The problem is locking overhead between sessions. Right now we avoid
all of that, and I think if we just put the value in PGPROC, it will be
good enough with limited locking required.
--
Bruce Momjian <bruce(at)momjian(dot)us> http://momjian.us
EnterpriseDB http://enterprisedb.com
+ Everyone has their own god. +
| From | Date | Subject | |
|---|---|---|---|
| Next Message | Tom Lane | 2014-05-15 16:39:03 | Re: Unportability of setvbuf() |
| Previous Message | Alvaro Herrera | 2014-05-15 15:48:01 | Re: Unportability of setvbuf() |