Parallel_execution_message

From: Wolfson Larry - lwolfs <lawrence.wolfson_at_acxiom.com>
Date: Mon, 11 Oct 2004 20:15:52 -0500
Message-ID: <433A07749711884D8032B6A0AB11526203CE25D5@conmsx07.corp.acxiom.net>

Does anyone have the skinny on this? I ran into one of our DBAs from another office and he was telling me about huge improvements in sorts, using this.

I found the stuff below et. al., but I didn't a clear picture of how you decide how big it should be and what all it affects.

I did see some HP example on 10G with it set to 16K.

	TIA
	Larry


Jeff Marsh
	Optimizing Parallel Query in Oracle 8i

http://www.evdbt.com/PX%202003.pps

http://www.phptr.com/articles/article.asp?p=169538&seqNum=6

>From 10G DataGuard:

Set PARALLEL_EXECUTION_MESSAGE_SIZE = 4096

When using parallel media recovery or parallel standby recovery, increasing the PARALLEL_EXECUTION_MESSAGE_SIZE database parameter to 4K (4096) can improve parallel recovery by as much as 20 percent. Set this parameter on both the primary and standby databases in preparation for switchover operations. Increasing this parameter requires more memory from the shared pool by each parallel execution slave process.

The PARALLEL_EXECUTION_MESSAGE_SIZE parameter is also used by parallel query operations and should be tested with any parallel query operations to ensure there is sufficient memory on the system. A large number of parallel query slaves on a 32-bit installation may reach memory limits and prohibit increasing the PARALLEL_EXECUTION_MESSAGE_SIZE from the default 2K (2048) to 4K.

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Received on Mon Oct 11 2004 - 20:11:21 CDT

Parallel_execution_message_size