November 11, 2019 at 2:15 pm
Hello,
My database server memory utilisation is growing faster from past 1 week. it remained same for 1 week around 55% and now it is going to 70% and increasing.
Total OS memory is 32GB and I kept cap for sql server memory upto 29GB. Dont know what to do
thanks
iosman
November 11, 2019 at 2:22 pm
29GB out of 32 is about 90%, so what's the problem with it using 70%? SQL Server will grab as much memory as you give it and won't usually give it back - that's the way it works. The more memory it can use, the better it'll perform.
John
November 11, 2019 at 2:48 pm
Yes, don't worry about this. (I would personally cap Max Server Memory at 26 GB on that server, but that's within tolerance.)
November 11, 2019 at 4:15 pm
I have to disagree a bit here. Changing from 55% memory utilization to 70% is almost a 30% increase in required memory.
I'd do a search for one of the many scripts out there that tell you what's using memory and how much. I'd start collecting the output of that in a "DBA table" somewhere on a regular scheduled basis to hopefully find what's actually causing the usage. I'd also start checking the execution plan of at least the worst offenders.
--Jeff Moden
Change is inevitable... Change for the better is not.
November 11, 2019 at 4:27 pm
It depends how much data is in the databases. If I had allowed 29GB max server memory, and I had a 29GB database, I'd be perfectly happy for all the memory to be used. Once you do reach the max server memory, then you need to make sure that pages aren't being churned in and out of memory, plans aren't being prematurely evicted from cache, queries are getting appropriate memory grants, and so on.
John
November 11, 2019 at 4:58 pm
I wouldn't increase the amount of memory you give to SQL Server, 29GB out of 32GB is already quite high. You need to leave enough memory for the operating system and anything else that's running on the machine. If you allocate more memory to SQL Server you might find everything else runs slow on the machine including things like SSMS. I'd try a lower figure, I'd normally go with 25GB to 27GB allocated to SQL Server if I had 32GB installed.
I wouldn't worry too much about the memory usage, SQL Server will grab memory to just cache data. We've got databases that would use many times the available memory on the machine but they still run well with less memory.
November 12, 2019 at 8:52 am
Jonathan, yes, I agree. I wasn't suggesting giving SQL Server more memory - I was just saying that I'd be comfortable with it actually using the memory that I had chosen to allocate to it.
John
November 12, 2019 at 3:37 pm
I've gotta say it again...
While I agree that this doesn't appear to be a problem of any kind, it is a sudden almost 30% increase in usage from the "baseline". It could be an early harbinger of a problem or a user that needs to be pork chopped. I wouldn't just ignore it. I'd try to see what was causing it and determine if it is becoming a problem.
--Jeff Moden
Change is inevitable... Change for the better is not.
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