Re: Optimizing Database High CPU

Alright will try the upgrade.

> Is it a few transactions updating a lot of rows each, or many transactions updating a few rows each?
It is a lot of transaction updating a few rows.

Then will look into a connection pooler.

Thanks for the response.

On Wed, Feb 27, 2019 at 2:01 PM Michael Lewis <mlewis@entrata.com> wrote:
>>
>> If those 50-100 connections are all active at once, yes, that is high.  They can easily spend more time fighting
eachother over LWLocks, spinlocks, or cachelines rather than doing useful work.  This can be exacerbated when you have
multiplesockets rather than all cores in a single socket.  And these problems are likely to present as high Sys times. 
>>
>> Perhaps you can put up a connection pooler which will allow 100 connections to all think they are connected at once,
butforces only 12 or so to actually be active at one time, making the others transparently queue. 
>
>
> Can you expound on this or refer me to someplace to read up on this?
>
> Context, I don't want to thread jack though: I think I am seeing similar behavior in our environment at times with
queriesthat normally take seconds taking 5+ minutes at times of high load. I see many queries showing buffer_mapping as
theLwLock type in snapshots but don't know if that may be expected. In our environment PgBouncer will accept several
hundredconnections and allow up to 100 at a time to be active on the database which are VMs with ~16 CPUs allocated
(somemore, some less, multi-tenant and manually sharded). It sounds like you are advocating for connection max very
closeto the number of cores. I'd like to better understand the pros/cons of that decision. 



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