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Resetting DMVs


Resetting DMVs

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Steve Jones
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Comments posted to this topic are about the item Resetting DMVs

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Stewart "Arturius" Campbell
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I agree wholeheartedly with this post.
Trying to troubleshoot a crashed SQL Server instance, without DMV data, is an extremely difficult task.

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Well said. Index usage stats are particularly revealing.

I'm in the process of deprecating and consolidating systems and key weapon in the arsenal is being able to proove categorically that the data has not been read in any way other than by system processes.

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Gary Varga
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I agree. Also, default to save and make it configurable as those databases which may require it to be off are exactly the ones with a professional DBA to evaluate the choice.

Gaz

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Simon D Richards
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This would work, especially if there is a default retention time for the data, any data beyond that would be cleared out by a garbage collector, and any databases that need extra special trouble shooting can be extended, for analysis.

This would also save all the un-managed systems that exist out there from becoming bloated with months of unused dmv data.
Jeff Moden
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That got me thinking. Why is this data removed? I'm sure some of the data is stored in memory and automatically reset, but is this the best way to handle this data? Wouldn't it be better to persist this data and allow the DBA to reset values when they were ready?


BWAA-HAA!!! I really have to laugh at this one. Welcome to the nature of "Agile" programming. :-P If enough people bitch about it, maybe they'll make it so 2 or 3 revs from now. Hmmm... ironically, that would put it out around 2020, the year of "perfect vision". Hehe

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Stephen_W_Dodd
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Couldn't you accomplish the same thing with extended events?
TravisDBA
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Because these DMV's are directly tied into the Performance Dashboards that people use everyday in order to get an updated POINT IN TIME look at their SQL Server and their databases. Secondly, these DMV's just don't have enough cache available for historical performance, that's why. Even if the cache was large enough, as you stated there would probably be performance issues that would result from doing that anyway. However, you can set up a "DMV repository" by just creating specific jobs to warehouse all DMV results in a specific repository at particular intervals that could be stored in msdb or somewhere else like a DBA Utility database for example. Here is a link that will give you a good starting point for doing just that:

http://www.sqlserverpath.org/2012/03/31/better-dba-dashboards-using-dmv-monitors-14/

:-D

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aleksey2001
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Microsoft will implement it eventually. Just like Oracle did few years ago. Oracle has a separate AWR repository to store this type of information. Just wait =)
SQLRNNR
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Jeff Moden (3/13/2013)
That got me thinking. Why is this data removed? I'm sure some of the data is stored in memory and automatically reset, but is this the best way to handle this data? Wouldn't it be better to persist this data and allow the DBA to reset values when they were ready?


BWAA-HAA!!! I really have to laugh at this one. Welcome to the nature of "Agile" programming. :-P If enough people bitch about it, maybe they'll make it so 2 or 3 revs from now. Hmmm... ironically, that would put it out around 2020, the year of "perfect vision". Hehe


+1



Jason AKA CirqueDeSQLeil
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