When tuning queries, ignore the fact that explain plan shows a cost. The optimizer finds the lowest cost it can. If you mess with hints you will almost certainly get a higher cost. I've tuned queries that ran for hours with a cost of less than 10 -- the tuned versions had costs in the hundred-billions and ran in seconds.
Secondly, you can alter session your hash_area_size up and noone will be the wiser. Kevin -----Original Message----- Sent: Wednesday, September 17, 2003 12:25 PM To: Multiple recipients of list ORACLE-L i explain planned it and it was much worse than not exists. my understanding is hash_aj is faster when the table in the sub-query returns results that are significantly less than the one in the outer table. ill try it, but i think exists is faster. we dont want to do an index scan here and my hash_area_size isnt real big. > > From: "Richard Ji" <[EMAIL PROTECTED]> > Date: 2003/09/17 Wed PM 12:04:56 EDT > To: Multiple recipients of list ORACLE-L <[EMAIL PROTECTED]> > Subject: RE: tuning a massive delete > > Try anti hash join. > > -----Original Message----- > Sent: Wednesday, September 17, 2003 11:45 AM > To: Multiple recipients of list ORACLE-L > > > i have a table with 27 million records that is about 1.2 GB in size. I have a 'staging table' with 18 million records. 16 million records have a 'delete' flag. I have indexed the column in staging with a delete flag. both tables have indexed primary keys. Is the following my fastest option or would an 'IN' be faster? Im concerned because this has been running for a while and have alot of consistent gets but no 'writes' yet which tells me its still building the join. Our sort_area_size is rather small and Im not allowed to change it which tells me we are swapping to the temp tablespace. > > anyway to speed this up? or is this the fastest we got? > > > create table ani_prx_new parallel (degree 5) nologging > as select * > from ani_prx b > where not exists (select 1 from bo_owner_stage.ani_prx a where ba_reccode = 'V' and a.cusip = b.cusip > and a.fund_no = b.fund_no and a.add_cymd = b.add_cymd) > > -- > Please see the official ORACLE-L FAQ: http://www.orafaq.net > -- > Author: <[EMAIL PROTECTED] > INET: [EMAIL PROTECTED] > > Fat City Network Services -- 858-538-5051 http://www.fatcity.com > San Diego, California -- Mailing list and web hosting services > --------------------------------------------------------------------- > 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). > -- > Please see the official ORACLE-L FAQ: http://www.orafaq.net > -- > Author: Richard Ji > INET: [EMAIL PROTECTED] > > Fat City Network Services -- 858-538-5051 http://www.fatcity.com > San Diego, California -- Mailing list and web hosting services > --------------------------------------------------------------------- > 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). > -- Please see the official ORACLE-L FAQ: http://www.orafaq.net -- Author: <[EMAIL PROTECTED] INET: [EMAIL PROTECTED] Fat City Network Services -- 858-538-5051 http://www.fatcity.com San Diego, California -- Mailing list and web hosting services --------------------------------------------------------------------- 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). -- Please see the official ORACLE-L FAQ: http://www.orafaq.net -- Author: Kevin Toepke INET: [EMAIL PROTECTED] Fat City Network Services -- 858-538-5051 http://www.fatcity.com San Diego, California -- Mailing list and web hosting services --------------------------------------------------------------------- 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).
