Hi John,
Is your Informix on cooked devices ?
Are you using ver 12.10 and above ?
Do you notice sequential scans on system catalog tables (like sysdistrib etc) ?
Do those tables appear top of the sequential counts ?
We have noticed similar CPU (degraded) efficiency on our high OLTP DB.
Also noticed that system catalog tables were doing lot of sequential counts
We implemented the following:
a) update statistics high on offending system catalog tables
b) zero profile counts (onstat -z)
c) run find sequential scans query again
It should now
not show system catalog tables and your CPU efficiency will improve.
Additional Note:
If you are using AWS EC2 instances, you can definitely see a big drop in the graph for "EBS: Average I/O across all volumes"
PS: There is no 'official' documentation from IBM/HCL about updating system catalog tables. Please be aware of this and any side effects.
HTH
Regards
Mallik
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Mallik Damaraju
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Original Message:
Sent: Wed November 17, 2021 08:31 AM
From: John Smith
Subject: CPU efficiency
Virtual machine
regards
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John Smith
Original Message:
Sent: Wed November 17, 2021 08:00 AM
From: Jon Ritson
Subject: CPU efficiency
Is this on a REAL machine or a Virtual machine?
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Jon Ritson
Original Message:
Sent: Wed November 17, 2021 03:33 AM
From: John Smith
Subject: CPU efficiency
Hello
seen with onstat -g glo on a heavy OLTP server , CPU efficiency is about 40% ?
do i need to change some parameters (VPCLASS CPU ...other ?)
Thanks
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John Smith
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#Informix