Re: Informix hogging CPU

In article <wrafh3md69.fsf@tglobe3.tollpost.no>, =?iso- 8859-1?q?=D8yvind_Gjerstad?= <ogj@tglobe3.tollpost.no> writes >"Mike Matthews" <mmatt@halcyon.com> writes: > >> I am running Informix Online Server version 7.1 on D250, one cpu, HPUX >> 10.10. When Informix gets hit with an SQL statement doing a few joins an a >> 35,000 record database, the system just crawls while the statement >> executes (takes about 5 minutes). No one can login and if you are logged >> in, you get a response to hitting ENTER about 40 seconds after hitting it. >> TOP shows oninit processes running with a priority of -16 and oninit >> processes using about 90% of the CPU. I don't see any obvious errors in >> the ONCONFIG file. Has anyone seen anything like this and is there any way >> of configuring Informix to use less CPU? > a) Run the query with in dbaccess with SET EXPLAIN ON; before it an look at the sqexplain.out file produced Any "SEQUENTIAL SCAN" list or DYnamic Hash Join on a large table means an index is missing on that table. b) Check your UNIX kernel parameters that the number of semaphores and semaphore sets is > 400. c) Make sure the query is running with PDQPRIORITY=0 (or 1) no higher. -- David Williams