Re: Delete followed by Select Count(1) - SLOW

[JOE TESTA]

HWM, oracle will search up to the high water mark when doing a count, like you proposed, so if you're gonna delete all of the rows anyways, save time(now and later) by doing the truncate.   joe >>> [EMAIL PROTECTED] 08/16/01 05:32PM >>> I have a user that deleted all of the rows in a table (i.e. 100,000), waited for it to complete, and then ran a SELECT COUNT(1) FROM <table>. It took a few minutes for '0 rows' to be returned to the prompt. The table has ~60 extents (128k ea.). Granted, the number of extents is excessive but it's a development instance and this table is an exception. Is Oracle scanning through all of the blocks, since the space wasn't released, and this is the cause of the latency? The curious thing is that I told this user to use TRUNCATE instead and we talked about using the drop/reuse storage clauses. He performed a TRUNCATE...REUSE STORAGE and the same select and it was night and day in terms of performance. If the allocated space isn't being released in this case also, why is there such a performance difference between the two? -w __________________________________________________ Do You Yahoo!? Make international calls for as low as $.04/minute with Yahoo! Messenger http://phonecard.yahoo.com/ -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Walter K   INET: [EMAIL PROTECTED] Fat City Network Services    -- (858) 538-5051  FAX: (858) 538-5051 San Diego, California        -- Public Internet access / Mailing Lists -------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from).  You may also send the HELP command for other information (like subscribing).