Re: parse_calls/executions ratio

From: Yong Huang <yong321_at_yahoo.com>
Date: Tue, 10 Mar 2009 11:13:24 -0700 (PDT)
Message-ID: <930951.96714.qm_at_web80608.mail.mud.yahoo.com>


> This implies that a statement is being parsed at least once without being executed.

At least in the case of parallel executions, it can happen. I answered this same question at a Chinese Oracle site:

"One important case I want to add to what Tom Kyte says is that if the SQL is run in parallel, the SQL will be parsed multiple times by the query coordinator and all parallel slaves I assume, but this particular SQL itself is only executed by the query coordinator, because after each slave parses it, the slave creates its only SQL with slightly different sql_text (and therefore hash_value and sql_id)."

I posted it at http://www.itpub.net/archiver/tid-1112877.html

Yong Huang       

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Received on Tue Mar 10 2009 - 13:13:24 CDT

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