| From: | Xiaoning Ding <dingxn(at)cse(dot)ohio-state(dot)edu> |
|---|---|
| To: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
| Cc: | "Joshua D(dot) Drake" <jd(at)commandprompt(dot)com>, Scott Marlowe <smarlowe(at)g2switchworks(dot)com>, pgsql-performance(at)postgresql(dot)org |
| Subject: | Re: scalablility problem |
| Date: | 2007-03-31 17:08:25 |
| Message-ID: | 460E9589.6070103@cse.ohio-state.edu |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-performance |
Tom Lane wrote:
> "Joshua D. Drake" <jd(at)commandprompt(dot)com> writes:
>>> I use RHEL 4. I can not understand how the scalability related with
>>> shared memory?
>
>> It isn't RHEL4 and shared memory. It is PostgreSQL and shared memory.
>> Things have changed with PostgreSQL since 7.3 (7.3 is really god awful
>> old) that allow it to more effectively access shared memory and thus
>> provide better performance.
>
> Some specifics:
>
> * bufmgr algorithms redesigned to allow larger number of shared buffers
> to be used effectively
>
> * bufmgr redesigned to not have a single lock for management of all
> shared buffers; likewise for lockmgr
>
> * lots of marginal tweaks such as paying attention to cache line
> alignment of "hot" shared data structures
>
> I'm probably forgetting some things but I think the bufmgr and lockmgr
> changes were the biggest improvements in this area.
>
> regards, tom lane
That is very helpful. Thanks!
Xiaoning
>
>
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