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Old 03-07-08, 07:09
rahul_s80 rahul_s80 is offline
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Page cleaners Tuning

we are having some 4 hrs constant load performance tests going on where the final readings comes some what like these

db2 9.1.3
windows
------------

Buffer pool data writes = 21341
Asynchronous pool data page writes = 15711
Buffer pool index writes = 5134841
Asynchronous pool index page writes = 152345

LSN Gap cleaner triggers = 10899
Dirty page steal cleaner triggers = 574
Dirty page threshold cleaner triggers = 99589

-------------

sum of all Bufferpool ~ 2GB
softmax 1000
logfilsz 12000
CHNGPGS_THRESH 25
NUM_IOCLEANERS AUTOMATIC
-------------


even though the % steal is quite low but isn't in our case the page cleaners
are getting fired too aggresively.
can someone please recommend some better cfg

regards
Rahul
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Old 03-07-08, 07:42
azs0309 azs0309 is offline
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increase ur CHNGPGS_THRESH in increment of 5 and test..may be 30-40 would be a good range
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Old 03-07-08, 07:48
rahul_s80 rahul_s80 is offline
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thanks,
but dont you think synch write is happening too often than asynch writes.
i am really bothered because of that. wont delaying cleaning would increase it further ?
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Old 03-07-08, 08:23
azs0309 azs0309 is offline
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check how many page cleaners are active at a time, so u would get an idea..then if u see more steal cleaner triggers..try to increase it...its just a thought..test it thoroughly...
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Old 03-11-08, 16:26
db2rocks db2rocks is offline
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Set DB2_USE_ALTERNATE_PAGE_CLEANING registry variable on..That will help you
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Old 03-12-08, 01:14
Marcus_A Marcus_A is offline
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Quote:
Originally Posted by db2rocks
Set DB2_USE_ALTERNATE_PAGE_CLEANING registry variable on..That will help you
This will cause the page cleaners to fire more agressively.

Regarding the original post, I think you are worrying about a problem that does not exist.
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