Re: vacuumdb causes memory drain.

Performance issue.

Can I restrict memory usage at session level in the script where I run
Vacuum DB ?

> On Apr 27, 2018, at 2:06 AM, Laurenz Albe <laurenz(dot)albe(at)cybertec(dot)at> wrote:
>
> Sushil Shirodkar wrote:
>
>>>> On Thu, Apr 26, 2018 at 10:31 AM, Sushil Shirodkar <sushilps(at)hotmail(dot)com> wrote:
>>>> Running "vacuumdb -a -z -v" from the cron on one of our test environment, and
>>>> noticed that memory of the server goes down from 3.4GB free to 150MB. Once
>>>> the process is over, memory is not released, is it normal or something needs to be
>>>> changed ? also other processes start running slow afterwards due to low memory.
>>>
>>> How are you measuring free memory? Memory might be listed in cached/buffers instead of
>>> free but is still available. Although that wouldn't then explain other processes being slow.
>>
>> I have put some small script which runs in a loop with "free -h" command,
>> while I am running "vacuumdb". Once I clear by "sync" or bounce PG,
>> everything runs normal afterward.
>
> Then I would say everything is fine.
> It is normal for a Linux system to have almost no free memory; the memory is used
> for the file system cache.
>
> Do you experience any problems, like reduced performance or high I/O?
>
> Yours,
> Laurenz Albe
> --
> Cybertec | https://www.cybertec-postgresql.com