July 31, 2014 at 1:22 am
Hello.
Is it possible that in 2012 there are more compilations than 2008?
I detected with traces and the DMV sys.dm_os_performance_counters that recompilations are more and less the same, but the number of compilations is much bigger than 2008 using the same application.
How the most of the eventsubclass in the recompilations are by statistics changed, is it possible that in 2012 the number of compilations is bigger than 2008 also by statistic changed?
Thanks.
July 31, 2014 at 4:36 am
Statistics changes will lead to a recompilation, not a compilation, as plans in cache are invalidated and they are recompiled due to the statistics updates.
I haven't compared just compile statistics between the servers, so I'm not sure. But if you're not seeing excessive recompiles, I wouldn't sweat it.
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July 31, 2014 at 5:07 am
Thanks for your answer.
Really, it doesn't seem that there is a negative impact in the throughput, but i don't sure because the DMV doesn't lie... or yes?
July 31, 2014 at 7:01 am
The DMV is going to readout what it gets from the performance counters, yes. Are there changes in behavior between 2008 and 2012? Yes. Will those changes possibly be evidenced by a change in compiles? Probably, but again, not something I've specifically tested or researched. Does a difference in just the compile count, and nothing else, between 2012 and 2008 mean there's something to worry about? I'd say no.
"The credit belongs to the man who is actually in the arena, whose face is marred by dust and sweat and blood"
- Theodore Roosevelt
Author of:
SQL Server Execution Plans
SQL Server Query Performance Tuning
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