| Plan-table [message #154485] |
Sun, 08 January 2006 23:18  |
IA
Messages: 91
Registered: March 2004
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Member |
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Hi Everyone
I have the final plan output, but would like to understand some keys statistics.
Please see attached document below, it is in MS WORD format, but I renamed it plan.sh for upload purposes.
I would like to understand the stats
1. COST=620K (24). Does this mean average CPU cost is 24%, or is this percentile for the SELECT STATEMENT step only?
2. Time = 02:04:05. Is this the time estimated to be taken by this step only. OR, to get an estimate as to how long the query will take, I should sum all rows in the TIME column of the explain plan?
Thanks
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Attachment: plan.sh
(Size: 19.50KB, Downloaded 1380 times)
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| Re: Plan-table [message #154789 is a reply to message #154485] |
Tue, 10 January 2006 10:50  |
smartin
Messages: 1803
Registered: March 2005
Location: Jacksonville, Florida
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Senior Member |
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This is a strange plan.
Should be cumulative, but for that line. So you don't have to add the cost and time lines. The select statement is for the entire query, so the numbers at the top are the total. Some steps don't add much or anything to the cost estimates, kinda like they are "for free". So the lines above already take into account the estimates from ealier, nested steps.
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