Re: lchwaits, read aheads

Manoj wrote: > > All, > > Are there any guidelines for the below ? > > ixda-RA idx-RA da-RA RA-pgsused lchwaits > 4398 29 27805 32188 55 This shows that the Informix read-ahead logic has prefetched 4398 index leaves, 29 index nodes, and 27805 data pages for a total of 32232 pages. You have actually used 32188 of those prefetched pages for a Read-Ahead utilization rate of 99.86%. Pretty impressive. It shows that you might benefit from increasing the Read-Ahead parameters in the ONCONFIG file slightly. The latchwaits shows how often processes are having to block (spinwaits are not counted here) because they cannot get access to a shared memory resource. Unless the statistics were cleared in the last minute or less (tbstat -z) 55 lchwaits is great. I just cleared stats on one of our servers and about ten minutes later we had 208 lchwaits with 432491 isamtot operations (just so you can judge). Art S. Kagel