prefecth* parameters how to tune

Posted by Valeriy Bashkatov on 20-Oct-2015 03:35

Hello,

Is there are recommendations for tune prefetch* parameters (-prefetchDelay, -prefetchFactor <n>, -prefetchNumRecs <n>, -prefetchPriority <n>)? How to know whether it is necessary to change their values?

Posted by ChUIMonster on 20-Oct-2015 09:25

I suggest that enabling -prefecthDelay and setting -prefetchFactor 100 are simple and sensible.  I mentioned in the other thread that I have not seen any downside to either.

Packing the messages fuller will work better if you also set -Mm to a non-default value.  -Mm 8192 is a good start.

To monitor the effectiveness look at the number of records per message.  You can get that from the _actServer VST.  Or you can just look at the ProTop "servers" screen.

All Replies

Posted by George Potemkin on 20-Oct-2015 09:13

Some More Database Performance Knobs

North American PUG Challenge

Richard Banville

pugchallenge.org/.../NEPUG_Performance.pptx

Posted by ChUIMonster on 20-Oct-2015 09:25

I suggest that enabling -prefecthDelay and setting -prefetchFactor 100 are simple and sensible.  I mentioned in the other thread that I have not seen any downside to either.

Packing the messages fuller will work better if you also set -Mm to a non-default value.  -Mm 8192 is a good start.

To monitor the effectiveness look at the number of records per message.  You can get that from the _actServer VST.  Or you can just look at the ProTop "servers" screen.

Posted by Valeriy Bashkatov on 21-Oct-2015 02:32

[quote user="George Potemkin"]

Some More Database Performance Knobs

North American PUG Challenge

Richard Banville

pugchallenge.org/.../NEPUG_Performance.pptx

[/quote]

Unfortunately, the slides without author's comments I do not understand (
But thanks anyway, George!

Posted by Valeriy Bashkatov on 21-Oct-2015 02:33

[quote user="ChUIMonster"]

I suggest that enabling -prefecthDelay and setting -prefetchFactor 100 are simple and sensible.  I mentioned in the other thread that I have not seen any downside to either.

Packing the messages fuller will work better if you also set -Mm to a non-default value.  -Mm 8192 is a good start.

To monitor the effectiveness look at the number of records per message.  You can get that from the _actServer VST.  Or you can just look at the ProTop "servers" screen.

[/quote]

Thank you, Tom!

This thread is closed