3-68 IBM Informix OnLine Database Server Administrator’s Guide

Monitor Buffer-Pool Activity

Monitor Buffer-Pool Activity
Monitor buffer-pool activity to determine the general availability of buffers
and to isolate the activity that is triggering buffer-pool flushing. (Refer also
topage 3-66 for general buffer statistics.)
Thetbstat -p output contains the following two statistics that describe buffer
availability:
Refer topage 7-92 for further information about the tbstat -p output.

tbstat -F

From the command line, executetbstat -F to obtain a count of the writes
performed by write type. Refer to page2-75 for a definition of each of the
following write types:
Foreground write
LRU write
Idle write
Chunk write
In addition,tbstat -F lists the following page-cleaner information:
Page-cleaner number and shared-memory address
Current state of the page cleaner
Details about the function and activities of the page-cleaner daemon
processes are described onpage 2-34. Refer to page7-87 for further infor-
mation about the tbstat -F output.
ovbuff liststhe number of times that OnLine attempted to exceed the
maximum number of shared buffers,BUFFERS. (The ovbuff
field appears in the third row of output, fourth position.)
bufwaits lists the number of times processes waited for a buffer (any
buffer). (Thebufwaits field appears in the fourth row of
output, first position.)