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writelog wait_type sys.dm_os_wait_stats reasonable number Expand / Collapse
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Posted Monday, May 5, 2014 10:12 AM
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I found a simple query on the web to evaluate my waitstats for log writes.

SELECT wait_time_ms
FROM sys.dm_os_wait_stats
WHERE wait_type = 'WRITELOG'

I am not having a performance issue but I noticed the results for the above query were in the millions of mili seconds.

What is a reasonable number for writelog waitstats and am I missing something obvious?

thanks

David



Post #1567593
Posted Monday, May 5, 2014 11:32 AM


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You have to keep in mind that this value is an accumulation since the last server restart, so if your server has been up for months a wait time in the millions isn't that much. I've got a server that's been up since December and the WRITELOG wait is over 6 million but that is only about 0.06% of the time the server has been up. You'd be better off looking at the % of total waits that WRITELOG is using.

Also a reasonable number for your system may not be a reasonable number for someone else's. You need a baseline and then you can find what is not reasonable (normal). If my logs are on SSD's and your's are on 7500RPM spinning disks, your number is not what I should be getting.




Jack Corbett

Applications Developer

Don't let the good be the enemy of the best. -- Paul Fleming

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