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Re: Cache hit rate

From: Joel Garry <joelga_at_pebble.org>
Date: Mon, 18 May 1998 19:30:20 GMT
Message-ID: <slrn6m135t.p8i.joelga@pebble.org>


On Mon, 18 May 1998 15:59:44 GMT, larionov_at_yahoo.com <larionov_at_yahoo.com> wrote:
>Sorry if this question(s) sounds silly!
>
>I want to improve the cache hit rate.
>Would it help If I decrease multiblock_read_count?
>
>On my system I have a bunch of random updates,
>where just one row is search-updated in a 5GB table.
>Of ourse I don't need to read 32 blocks to update
>just one row, so high multiblock_read_count is just a waste of
>SGA! Am I wrong?

This multiblock is for full table scans, so there is no effect on random updates (unless you don't have any indices, in which case you have worse problems... :)

Since you probably have some other tables that do get scanned, your cache hit rate would probably decrease by decreasing the count.

>
>Also, can I set the multiblock_read_count just for one table
>and leave untouched for other tables?

Only if it is the only table in your instance.

>What degree of paralellism on this table would be preferable?

See your Concepts manual.

>
>Thank you!
>
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Received on Mon May 18 1998 - 14:30:20 CDT

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