On 23/11/11 15:16, Carl (CBM) wrote: > One more DB performance report/question. I am seeing some UPDATE > queries that only change one row but take much, much longer than they > ought to. Is anyone else seeing this? > > For example, the following type of query is getting killed from time to > time in the p_enwp10 database on sql-s1. The query killers says it ran > for over 400 seconds before being killed. The update is on a primary > key, and I don't see any way to optimize it. At the time this is > running the database connection is inside a transaction (AutoCommit = 0) > if that matters. > > UPDATE tmpcategories > SET c_category = 'A-Class_Water_supply_and_sanitation_articles', > c_ranking = '425', c_replacement = 'A-Class' > WHERE c_project = 'Water_supply_and_sanitation' and c_rating= 'A-Class' > and c_type = 'quality' > > - Carl
I guess you could make the query sorter by splitting it adding a LIMIT clause, then rexecing while the affected rows = limit. (Assuming you don't need the UPDATE to be atomic) _______________________________________________ Toolserver-l mailing list ([email protected]) https://lists.wikimedia.org/mailman/listinfo/toolserver-l Posting guidelines for this list: https://wiki.toolserver.org/view/Mailing_list_etiquette
