IDS Forum

onstat -P shows high percentage of other pages

Posted By: Andreas.KUTSCHE@spar.at
Date: Tuesday, 29 March 2005, at 7:26 a.m.

Hello,

we switched recently from IDS.7.31.FD2 to IDS.940.FC5.
We have 16000000 BUFFERS configured (16 Mio).

48 minutes after a database restart onstat -P showed
the following BUFFER usage:
Data 36.83
Btree 22.21
Other 40.96

The 40.96% other were not unused pages (partnum 0), but
most of them belonged to two indices of a large fragmented
table:
partnum total btree data other dirty
12582998 2927190 4926 0 2922264 40
12582999 3374545 57185 0 3317360 211

After 2 hours and 39 minutes the BUFFER usage changed to:
Data 32.63
Btree 44.46
Other 22.91

partnums of a large fragmented table/index:
partnum total btree data other dirty
12582998 330928 3 0 330925 0
12582999 2715629 3 0 2715626 0


After 3 hours Other dropped to 18.55% .

Has anyone seen this behaviour before? What 'other' pages
should that be? The difference between allocated and used
pages for these indices is much less than 3 Mio pages each.

May this point to some issue with the new btree scanners?
At the moment we run 3 scanners with priority low,
threshold 10000 and rangesize 500.

Regards,
Andreas Kutsche

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