Page Life Expectancy

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Page Life Expectancy

sunny.tjk

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October 11, 2013 at 2:46 pm

#281336

Using a script, I got a number for PLE. How do I conclude that this PLE is optimum for my instance?

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George M Parker SSCertifiable Points: 5412 More actions · Answer 1

Please check out the bottom of Jonathan Kehayias's blog page below:

http://www.sqlskills.com/blogs/jonathan/finding-what-queries-in-the-plan-cache-use-a-specific-index/

To know whether your value is good or bad, you have to know what "normal" is. That means that you need to have a baseline value (or steady state as Jonathan refers to it) for PLE and then monitor for situations where it dips below that baseline value.

Gail Shaw SSC Guru Points: 1004504 More actions · Answer 2

George M Parker (10/11/2013)
To know whether your value is good or bad, you have to know what "normal" is. That means that you need to have a baseline value (or steady state as Jonathan refers to it) for PLE and then monitor for situations where it dips below that baseline value.

This.

There are very few counters where there's a hard number that's good or bad. Numbers are normal or not normal for your instance.

Gail Shaw
Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability

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Grant Fritchey SSC Guru Points: 398679 More actions · Answer 3

And remember, in addition to what everyone else has already correctly said about it, page life expectancy can change due to things that are not issues. It's pretty normal, for example, to see the page life expectancy fall to zero during weekly or nightly data loads and then rebuild during the day. So you have to watch this metric over time.

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Lynn Pettis SSC Guru Points: 442467 More actions · Answer 4

George M Parker (10/11/2013)
Please check out the bottom of Jonathan Kehayias's blog page below:
http://www.sqlskills.com/blogs/jonathan/finding-what-queries-in-the-plan-cache-use-a-specific-index/
To know whether your value is good or bad, you have to know what "normal" is. That means that you need to have a baseline value (or steady state as Jonathan refers to it) for PLE and then monitor for situations where it dips below that baseline value.

Let's make it easier for others to get to this blog:

http://www.sqlskills.com/blogs/jonathan/finding-what-queries-in-the-plan-cache-use-a-specific-index/

George M Parker SSCertifiable Points: 5412 More actions · Answer 5

George M Parker

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October 13, 2013 at 7:45 am

#1658119

Thanks Lynn!

dbassassin Ten Centuries Points: 1350 More actions · Answer 6

GilaMonster (10/11/2013)
George M Parker (10/11/2013)
To know whether your value is good or bad, you have to know what "normal" is. That means that you need to have a baseline value (or steady state as Jonathan refers to it) for PLE and then monitor for situations where it dips below that baseline value.
This.
There are very few counters where there's a hard number that's good or bad. Numbers are normal or not normal for your instance.

I second "that" I personally enjoy using Red Gate SQL Monitor and then using their baseline comparisons. The key is definitely watching when PLE falls and knowing what processes occur during this time.

Why is it that people who can't take advice always insist on giving it? - James Bond, Casino Royale