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PWAIT_MD_RELATION_CACHE and MD_LAZYCACHE_RWLOCK wait types


PWAIT_MD_RELATION_CACHE and MD_LAZYCACHE_RWLOCK wait types

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shollen
shollen
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I'm hoping someone can give me some more information on either of these two wait types PWAIT_MD_RELATION_CACHE and MD_LAZYCACHE_RWLOCK. We started seeing these happen on queries that were accessing a table with 1,000 records, most of the waits were over a couple minutes. No blocking was occurring at the time, and other queries against the database were able to complete successfully.

From doing a bit of research I was able to find this description on MSDN for PWAIT_MD_RELATION_CACHE: "Occurs during internal synchronization in metadata on table or index." This made me believe the issues was revolving around a large insert, update or delete that was occurring during that time, or manipulation of an index on the table. No records had been inserted or updated in the last 3 days, the indices were last rebuild 2 days prior to the issue.

I've been unable to find anything in relation to MD_LAZYCACHE_RWLOCK.

We are currently running Microsoft SQL Server 11.0.2100.60.

Any help or ideas would be appreciated.
rk 75674
rk 75674
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I had the same problem today.
The reason was probably, that the SQL-Server Process had taken all the available RAM. After limiting Maximum Server Memory and restart the problem was gone.
Hope it helps, Ralf Kuhlendahl
raulito.matias
raulito.matias
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I have the same problem with our production servers since last year and raised them to microsoft already. I'm very positive that the next release of CU will solve the problem for SQL 2012. :-)
raulito.matias
raulito.matias
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CU9 has been released:

http://support.microsoft.com/kb/2926712
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