SDS secondary using up nearly all memory

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darrella
Posts: 7
Joined: Sun Nov 06, 2011 6:52 pm
Location: Hobart

SDS secondary using up nearly all memory

Postby darrella » Tue Aug 25, 2020 11:15 am

We are using SDS for a production system, but the secondary getting ~99% memory utilisation, where more than half is with swap/page.

I've had a look through the SDS INI settings, but can't see anything obvious.

Are there any other config settings to manage this please ?

allistar
Posts: 156
Joined: Fri Aug 14, 2009 11:02 am
Location: Mount Maunganui, Tauranga

Re: SDS secondary using up nearly all memory

Postby allistar » Tue Aug 25, 2020 12:33 pm

Hi Darrell,
The [PersistentDb] DiskCacheMaxSegments tells the database server how much memory the database engine can use for disk cache. This is in units of 64Mb, so a setting of "40" allows it to use about 2.5Gb. Check this setting and make sure it's not too high.

Regards,
Allistar.

darrella
Posts: 7
Joined: Sun Nov 06, 2011 6:52 pm
Location: Hobart

Re: SDS secondary using up nearly all memory

Postby darrella » Tue Aug 25, 2020 12:54 pm

Thanks Allistar, we'll give that a try.

DarrellD

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BeeJay
Posts: 312
Joined: Tue Jun 30, 2009 2:42 pm
Location: Christchurch, NZ

Re: SDS secondary using up nearly all memory

Postby BeeJay » Tue Aug 25, 2020 12:55 pm

Hi Darrell,

<snip>...

Never mind, it looks like Allistar beat me to the punch regarding DiskCacheMaxSegments setting. You should also check the DiskCacheBlocksPerSegment setting in the [PersistentDb] section in case the default 64M size has been increased.

Cheers,
BeeJay.

JohnP
Posts: 73
Joined: Mon Sep 28, 2009 8:41 am
Location: Christchurch

Re: SDS secondary using up nearly all memory

Postby JohnP » Thu Aug 27, 2020 10:22 am

Note that the default for [PersistentDb] DiskCacheMaxSegments is half of physical memory, so if you haven't specified it, the db will try to take up that much. If you have multiple databases, three for instance, they all try to take half of physical memory. In other words, the default assumes only one database per machine.


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