> On Apr 27, 2018, at 8:39 AM, Laurenz Albe <laurenz.albe@xxxxxxxxxxx> wrote: > > Sushil Shirodkar wrote: >>>>>> On Thu, Apr 26, 2018 at 10:31 AM, Sushil Shirodkar <sushilps@xxxxxxxxxxx> 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? >>> >> Performance issue. >> >> Can I restrict memory usage at session level in the script where I run >> Vacuum DB ? > > Could you please bottom-post? > > Once vacuumdb is done, the associated backend process is gone too, so > it cannot consume any memory. > > Try to figure out which process consumes your memory. > > What do you get for free -h? > > How did you configure shared_buffers and maintenance_work_mem? > > Yours, > Laurenz Albe > -- > Cybertec | https://www.cybertec-postgresql.com Sorry for the delayed response. Process which was running close to 99% memory was "/usr/lib/postgresql/9.5/bin/postgres -D /var/lib/postgresql/9.5/main -c config_file=/etc/postgresql/9.5/main/postgresql.conf" free -h - was showing between 100-150 mb free. shared_buffers = 1GB maintenance_work_mem = 256MB
