Is it possible the alter index rebuild make the application too slow? After this command do we need to do analyze index? I guess
all stat for CBO will gone after this command? what's happened?
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Is it possible the alter index rebuild make the application too slow? After this command do we need to do analyze index? I guess
all stat for CBO will gone after this command? what's happened?
Rebuild index should make app run better, if anything. This would be because the rebuild re-organizes the index....removed deleted leafs, etc. It probably wouldn't hurt to analyze after a rebuild, but I don't think it's a must.
Analyzing index will infact improve the performance and I do analyze of some of the schemas in my database every day .
My options are :
estimate , 15%
I use DBMS_UTILITY.ANALYZE_SCHEME
rebuilding indexes is not a daily activity , but analyzing should be a daily one in order to provide a right feed to CBO to improve performance.
Thanks,
Madhu
Depends on how often the characteristics of your data changes.Quote:
Originally posted by mrvajrala
but analyzing should be a daily one in order to provide a right feed to CBO to improve performance.
I was once at a site where they had about 3 years of historical data. They loaded several million rows a day, but that didn't change the characteristics of the data. They computed statistics once every 6 months.
Guys, what's happened in my case was after I rebuild the index the application get slow significantly ( from other floors folks called me immediately and I paniced !! ) then I search google and find out someboy said do analyze tabel ... for all indexes and I did that and BOOM ... application get back to normal speed , no more complains I recieved. NOWHERE in Oracle Doc this is mention. Do you know why?? i really paniced!