deterministic behavior in embedded mode

[timbo]

We are using H2 in embedded mode on constrained hardware with read/write files. The data model is straightforward, the datasets are moderate in size, and the queries not particularly complex. 

The problem is that from time to time a query takes much longer to execute, like 20-100x longer. I expect some internal H2 housekeeping may be causing this (index rebuilding, defrag, compaction or other). Any ideas what tunings we might consider to limit this type of non-deterministic behavior? We have played with transaction log and cache sizing with little effect.

[Thomas Mueller]

Hi,

You could use the profiling tool to find out what the problem is. H2 doesn't normally do any special housekeeping, except for auto-analyze (you can disable this). But profiling will help you find out what the problem is.

Regards,

Thomas

 

On Tuesday, July 31, 2012, timbo wrote:

We are using H2 in embedded mode on constrained hardware with read/write files. The data model is straightforward, the datasets are moderate in size, and the queries not particularly complex. 

The problem is that from time to time a query takes much longer to execute, like 20-100x longer. I expect some internal H2 housekeeping may be causing this (index rebuilding, defrag, compaction or other). Any ideas what tunings we might consider to limit this type of non-deterministic behavior? We have played with transaction log and cache sizing with little effect.

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