| From: | Heikki Linnakangas <heikki(at)enterprisedb(dot)com> |
|---|---|
| To: | Praveen Kumar N <praveen_n(at)students(dot)iiit(dot)net> |
| Cc: | PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | Re: system cache and buffer cache |
| Date: | 2006-09-19 13:41:44 |
| Message-ID: | 450FF398.9030409@enterprisedb.com |
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| Lists: | pgsql-hackers |
Praveen Kumar N wrote:
> Hi,
> can anybody explain me what is the difference between system cache
> and buffer cache?
>
> I found that keywords in PostgreSql FAQ
> http://www.postgresql.org/docs/faqs.FAQ_DEV.html#item2.1
System cache is a per-row cache of system catalog tables. It's used to
speed up lookup of things like function names. It's implemented in
src/backend/utils/cache/syscache.c
Buffer cache is the cache managed by the buffer manager, that caches any
blocks from any relation used in the system. All access to relations go
through the buffer cache, using ReadBuffer/ReleaseBuffer (etc.) calls.
It's implemented in src/backend/storage/buffer/bufmgr.c
--
Heikki Linnakangas
EnterpriseDB http://www.enterprisedb.com
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