Re: 7.x performance issue on DEC Alpha

tolly brumbelow <tolly.brumbelow@bridge.bst.bls.com> writes: > Are you running the same application on both Alpha 1 and Alpha 2 ? >Have you checked to see if swapping is taking place on the unix side? >(if so you may have the buffers set to high) >Are you running update stats on Alpha 2 on a regular basis? >What does your onconfig file look like? >Check to make sure the temp dbspaces have the temp flag turned on? >(onstat -d and look for the T flag on the tempdbspaces) >Are the users accessing the database the same? >Run the queries with set explain on to see what path they are taking. >Make sure your update stats follows the guidelines in the performance We are running the same application on both Alpha 1 and Alpha 2. There is very little swapping going on unix side. Update stats is run regularly on Alpha 1 and since users on Alpha 2 access the database residing on Alpha 1 no update stats are done on Alpha 2. Temp dbspace have the temp flag turned on.. Users on both systems are accessing the database on Alpha 1 WE had installed a probe to collect the queries during the day and have run them so see what path they are taking and have already made adjustments to all the important queries and we are doing update stats based on the manual and as per Informix's consultant's advice. Some of the important onconfig parameters are : Locks 12000 Buffers 8000 Initial Shared Memory segment 300,000 additional shared mem 80,000 MULTIPROCESSOR 1 SINGLE_CPU_VP 0Number of CPU VPs 1 to start with and then one is added dynamically Kernel AIO Informix AIO VP is currently set to 4 but we plan to reduce it to 1 or 2 over this weekend OPTCOMPIND 2 onstat -g sch shows that the second CPU vp has 50% of it's cycle in Busy wait.... and if I reduce the CPU vps to one same queries start to take long time although sqexplain shows the same execution path..To me it looks like as if informix is generating major contention for all it's queries. A query which would take 2-3 seconds with 2 CPU vps will start to take 40-50 seconds with 1 CPU VP even through it is follownig index path... If you would like I can post the actual onconfig file and the outputs of onstat -g sch , iop, glo etc... - Rakesh