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Re: New database is slower on large select queries.

From: Niall Litchfield <n-litchfield_at_audit-commission.gov.uk>
Date: Tue, 29 Jan 2002 21:52:01 +0000 (UTC)
Message-ID: <a375i1$1l3$1@helle.btinternet.com>


Are you absolutely sure that it is the db and not the application?

"Kyle Singer" <ksinger_at_highspeed.com> wrote in message news:e239071f.0201290859.136cb8b9_at_posting.google.com...
> I'm no Oracle DBA so please be kind.
>
> We are currently using Oracle 8.1.5 on a single CPU Sun machine with
> 512MB RAM.
>
> We are testing 8.1.7 on a 4 CPU Sun machine with 1.5GB RAM. We have
> exp/imp our data onto the new database with success and most of our
> processes and procedures are a lot faster than the old DB.
>
> However, when we perform a query like 'select * from accounts' it is
> very slow. I may have tracked it down to queries with more than 16
> columns that select all data from a table. If I perform a query like:
>
> select accountid, name from accounts
>
> the query is very fast, faster than the old db.
>
> But even if I perform a query like:
>
> select name,name,name,name,name,name,name,name,
> name,name,name,name,name,name,name,name,
> name
> from accounts
>
> it is incredibly slow. Much slower than the old DB.
>
> When comparing the time it takes for a complete 'select * from
> accounts' between databases it takes 9 seconds on the old db and 80
> seconds on the new db.
>
> TOAD's database statistics screen is showing no warnings on the new DB
> and shows quite a few on the old DB.
>
> We've played with a few init parameters like db_block_buffers and
> shared_pool_size with no luck.
>
> The top command on the server indicated only 1% of CPU is used and a
> .1% iowait during the slow query. (I'm not sure that's what I should
> look at)
>
> Any ideas would be greatly appreciated!
>
> Thank you,
> Kyle Singer
> HighSpeed Communications
Received on Tue Jan 29 2002 - 15:52:01 CST

Original text of this message

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