Re: parallel query and latch waits

Which version of Oracle.

What is the

    serial run time
    parallel run time
    total wait time due to latches

Which latches are responsible for most waits ?

--
Jonathan Lewis
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Practical Oracle 8i:  Building Efficient Databases
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Rob Katofiasc wrote in message ...


>I have a table set up with parallel degree 4

>the table is spread out across 4 physical disk mounts.

>

>Everything run great except if I have a subquery

>

>i.e.

>

>select sum(impressions)

>from fact_table --parallel degree 4

>where user_id in (select user_id

>                   from users

>                   where  external_role_type IN('Named User', 'Registered

 User')


>                 )

>

>latch waits are 60% of non-idle wait time (from spotlight)

>What can I do to reduce this latch problem?

>

>If I remove parallel from the fact table I do not have a problem with

 latches?


>

>Thanks Rob