Wolfgang, Mladen, Paul Drake, Gints, and others: many thanks for your replies. First off -- this is a 3rd-party app with canned SQL. The db is intended to be a sort of small datamart that pulls from our prod SAP. I got paged on this at 2:00am last night, and was fighting it until 5:00am, so when I wrote the email this morning before coffee, I can only plead that I wasn't thinking quite clearly, and wrote the email prematurely. I say that because a short while after I wrote the email I finally realized that the data volume was all wrong. The database was tuned for a SAP pull that was has been about between 200K-500K records per night for the past year. Those 18 million row counts are an anomaly. After hunting down the team responsible for this app, I found out that instead of sending us the normal daily processing history, last night's SAP pull sent us all data going back to Feb 2004. Turns out the POC who asked for that amount of data, 1) didn't inform us in advance, and 2) wasn't sure how much data was going to be sent, or the consequences. I see from the replies, however, some areas in where I'm deficient, or can improve in, so for that, I'm grateful. Jeff T. -----Original Message----- From: Wolfgang Breitling [mailto:breitliw@xxxxxxxxxxxxx] Sent: Thursday, January 19, 2006 10:54 AM To: Thomas Jeff Cc: oracle-l@xxxxxxxxxxxxx Subject: Re: SQL Tuning -- large, long-running outer join query That query has no predicates whatsoever, apart from the join predicates and those are outer joins. What that means is that Oracle has to read every row of each of the five tables - at least once. Like Mladen, I wonder what the original business question is which this query is supposed to answer. I have the funny feeling that the developer(s) threw in the outer join "just in case" for good measure, especially on the last two outer joins. For the aql ASIS, I would try to replace the two "nested loop outer" with hash joins as well with full scans of IA_SALES_ORDLNS and OD_SALES_ORDLNS. And make sure you have the highest db_file_multi_block_read_count your OS can handle and potentially use parallel slaves. Thomas Jeff wrote: > We have this purchased app that is generating the following query. It > runs > for 8 hours then crashes due to ORA-1555. I'm reluctant to tinker > with the undo settings or increase the undo tablespace size, as it > appears from longops that this thing would likely run for another 7-8 > hours before > completing. I'm at a loss on how to tune this -- I can't touch the > physical structure, and I don't know enough to see any hints that could > possibly help. > > Any ideas? > > > SELET (boatload of columns) > FROM > TS_SALES_ORDLNS, /* 465,175 rows, 20,930 blocks */ > OD_SALES_ORDLNS, /* 18,733,125 rows, 1,247,303 blocks */ > IA_SALES_ORDLNS, /* 18,631,135 rows, 603,410 blocks */ > TS_SALES_ORDLNS_HD, /* 474,465 rows, 25,819 blocks */ > TS_SALES_ORDLNS_LN /* 472,645 rows, 14,043 blocks */ > WHERE > TS_SALES_ORDLNS.SALES_ORDER_NUM = > TS_SALES_ORDLNS_HD.SALES_ORD_NUM(+) > AND TS_SALES_ORDLNS.SALES_ORDER_ITEM = > TS_SALES_ORDLNS_HD.SALES_ORD_ITEM(+) > AND TS_SALES_ORDLNS.SALES_ORDER_NUM = > TS_SALES_ORDLNS_LN.SALES_ORD_NUM(+) > AND TS_SALES_ORDLNS.SALES_ORDER_ITEM = > TS_SALES_ORDLNS_LN.SALES_ORD_ITEM(+) > AND TS_SALES_ORDLNS.KEY_ID = OD_SALES_ORDLNS.KEY_ID(+) AND > TS_SALES_ORDLNS.KEY_ID =IA_SALES_ORDLNS.KEY_ID(+); > -- Regards Wolfgang Breitling Centrex Consulting Corporation www.centrexcc.com -- //www.freelists.org/webpage/oracle-l