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Need to reduce Engines

Oct 02, 2017 at 09:10 PM


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Former Member

Hi SAP Team

What sybase configurations we will need to look when we want to reduce Engine count?

ex - syb_default_pool Engine count is configured for 16 - we would like to bring it down to 12.

So - i will need to consider what other sybase configurations that would impact after we alter the engine thread count from 16 to 12

ex - we have currently configured "Config Partition" to the same count as the engine


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Can you throw some light on what triggered this ?

- Are current engines being under utilized ?

- Too many spinlocks ?

- Or just push from OS folks ?

DOP and number of parallel worker threads are two other configuration options that come to mind !


Former Member

Thanks Avinash

The driver is we plan to failover our sybase servers so that we can run 2 each on a single physical host . we have a 4 node cluster but they way it was designed it cant run 2 sybase instances on a single physical host ( 24 engines / 124 GB memory )

So we are ok to bring down the engine counts for these ASE servers - but when we do that we just want to make sure we review if any other sybase CFG's we need to modify as well


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1 Answer

Mark A Parsons Oct 03, 2017 at 05:20 PM

Check number of engines at startup to make sure <= 12.

Assuming you're running ASE 15/16 with kernel mode = threaded, you'll probably want to make sure you reduce the size of any thread pools that are > 12 in size (eg, syb_default_pool); see the alter thread pool command.

If you've configured your dataserver for parallel operations based on the number of engines, then you may want to reduce the associated config parameters, though they should still work (with perhaps some contention) with a reduced engine count; some config parameters that come to mind: number of worker processes, max * parallel degree.

Other configs I've rarely seen used ... explicit engine groups and/or execution classes based on engine numbers > 12; see sp_addengine, sp_dropengine, sp_engine, sp_bindexeclass, sp_dropexeclass, sp_showexeclass, sp_unbindexeclass

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Former Member

Thank Mark, yes we are using threaded mode.

In regards to the parallel operations we have them set to 1 - no we are not using them

max parallel degree 1 0 1 1number dynamic

max query parallel degree 1 0 1 1 number dynamic

max scan parallel degree 1 0 1 1 number dynamic

Yes we do not use explicit engine groups and/or execution classes