Re: row cache lock contention parallel insert
From: Randolf Geist <info_at_sqltools-plusplus.org>
Date: Mon, 21 Dec 2009 20:34:46 +0100
Message-Id: <997236621_at_web.de>
> The insert runs against different segments, against 16 to 64
> subpartitions, I understand that we should not observe locking in
> this situation (enq: TM Contention). We are not running several
> inserts such as
>
> insert /*+ append */ into t1 in different sessions
>
> We have
>
> insert /*+ append */ into t1
> insert /*+ append */ into t2
> insert /*+ append */ into t3
> insert /*+ append */ into t4
> insert /*+ append */ into t5
>
> In different sessions
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Date: Mon, 21 Dec 2009 20:34:46 +0100
Message-Id: <997236621_at_web.de>
> The insert runs against different segments, against 16 to 64
> subpartitions, I understand that we should not observe locking in
> this situation (enq: TM Contention). We are not running several
> inserts such as
>
> insert /*+ append */ into t1 in different sessions
>
> We have
>
> insert /*+ append */ into t1
> insert /*+ append */ into t2
> insert /*+ append */ into t3
> insert /*+ append */ into t4
> insert /*+ append */ into t5
>
> In different sessions
OK, thanks, re-reading your initial description I now see the "10" tables which I probably forgot while reading the remaining posts.
Still it is interesting that using the explicit partition pruning syntax changes the outcome of your test case.
Regards,
Randolf
Oracle related stuff blog:
http://oracle-randolf.blogspot.com/
Co-author of the forthcoming "OakTable Expert Oracle Practices" book: http://www.apress.com/book/view/1430226684 http://www.amazon.com/Expert-Oracle-Practices-Database-Administration/dp/1430226684
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