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Old 02-21-06, 19:22
NageshP NageshP is offline
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Question UDB - Export Utility Performance

Our system is on UDB 8.1 and we are using this command to export the data to a file....

time db2 "export to <file_name> of del modified by coldel@ select * from <table_name> where clause with ur"

while this runs, we monitored the file size change. File size increase stopped after 7min. But the utility reponded after 20min. Any idea what was the export utility doing for 13minutes after the file is created with records in the first 7min.

Apprepiate ur replies..

Thanks,
Nagesh
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Old 02-21-06, 21:47
sathyaram_s sathyaram_s is offline
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Are you doing a join of two tables ? Or is it a single table query as your example shows ?

In the former case, it may be that in the first 7 minutes, it had selected x number of records while still performing joins ... It wouldn't have been able to find a matching row for the next 13 mins .. (Poor performance, but theoretically possible)

In the latter case, it is not a 'normal' thing

Cheers
Sathyaram
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Old 02-21-06, 22:26
NageshP NageshP is offline
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hmm, good thought. It is a single table query though.

where clause is on a field which is indexed. Don't know if the utility is doing table scan instead of using the index. Is there a way we can check the access path of the export utility?

-- Nagesh
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Old 02-22-06, 03:02
sathyaram_s sathyaram_s is offline
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Use the usual explain tools on the select stmt .

Sathyaram
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