Re: Performance problems

Sounds like a truly evil bug I squashed in our 5.01 (or was it 5.05, whatever...) system a couple of years ago - check for negative numbers in the NPUSED column of systables. Makes the optimizer come up with some awful plans, which manifest themselves in lousy performance. It made our deadly slow server take off and fly, it was a real handicap. It happens I think when you do mass mods to a table with stored procedures (or triggers presumably) then update stats or somesuch. A table reorg/recreate (a la dbexport / dbimport) makes the problem go away for a while. It'll be back though. I'll bet if you Explain the slow SQL, you'll see a really bad plan generated by the optimizer. It's like making the optimizer work after a lobotomy. That's really getting to be an old version of online, any chance of upgrading to like 5.08ish(should be free...) or 7.x (won't be free)? Greg Doron Rippel wrote: .> .> Hi, .> .> We have the same database system on multiple machines at hundreds of .> customer sites. It is based on Online 5.01. .> .> At several sites, a severe performance problem has developed. At some .> sites, this slowed down SELECTs. At some - UPDATEs involving a specific .> trigger became very slow (and this was at the trigger condition .> evaluation stage, which was false, so that the trigger action was .> actually never activated). .> .> The database tables were not fragmented, no indexes were missing or .> corrupted at these customer sites. tbcheck -cIn and -cDn revealed no .> problems in regular tables or in sys tables. Dropping and re-creating .> the indexes did not help. .> .> At some other customer sites, with much larger databases of the same .> structure and same application - there were no complaints at all .> .> The only thing that solved this strange problem was dbexporting, .> dropping the database and then dbimporting it back. This increased the .> transaction speed 10-15 times. .> .> Any guess what's going on? Maybe some obscure sys tables corruption that .> dbimport re-builds? .> .> Doron Rippel .> doron@usa.net