> I think it could fail that way for two reasons: /dev/shm size limit
> (mount option, which I think you are saying you have set to 4GB?), or
> your system ran out of RAM +swap.
df /dev/shm
Filesystem 1K-blocks Used Available Use% Mounted on
shm 4194304 351176 3843128 9% /de
On Wed, Jul 10, 2019 at 12:27 AM Konstantin Malanchev wrote:
> I'm executing the query with smaller work_mem, it will take some time. But I
> still confused why it used all /dev/shm (4GB) and fails with "no space left"
> error while work_mem = 512MB.
I think it could fail that way for two reaso
Thank you!
> For example, if you have one Parallel Hash Join in your plan, it could
> allocate up to 512MB * 3 of shared memory (3 = leader process + 2
> workers).
I'm executing the query with smaller work_mem, it will take some time. But I
still confused why it used all /dev/shm (4GB) and fails
On Tue, Jul 9, 2019 at 11:11 PM Konstantin Malanchev wrote:
> Thank you for explanation. work_mem = 512MB and
> max_parallel_workers_per_gather = 2 and I run only one Postgres instance and
> only one query. EXPLAIN shows "Workers Planned: 2" for this query. Why it can
> use more than 1GB of /de
Hello Thomas,
Thank you for explanation. work_mem = 512MB and max_parallel_workers_per_gather
= 2 and I run only one Postgres instance and only one query. EXPLAIN shows
"Workers Planned: 2" for this query. Why it can use more than 1GB of /dev/shm?
Konstantin
> On 9 Jul 2019, at 13:51, Thomas
On Tue, Jul 9, 2019 at 10:15 PM Jean Louis wrote:
> * Konstantin Malanchev [2019-07-09 12:10]:
> > I have 8 GB RAM and /dev/shm size is 4GB, and there is no significant
> > memory usage by other system processes. I surprised that Postgres uses more
> > space in /dev/shm than sharred_buffers par
* Konstantin Malanchev [2019-07-09 12:10]:
> Hello Jean,
>
> I have 8 GB RAM and /dev/shm size is 4GB, and there is no significant memory
> usage by other system processes. I surprised that Postgres uses more space in
> /dev/shm than sharred_buffers parameter allows, probably I don't understand
Hello Jean,
I have 8 GB RAM and /dev/shm size is 4GB, and there is no significant memory
usage by other system processes. I surprised that Postgres uses more space in
/dev/shm than sharred_buffers parameter allows, probably I don't understand
what this parameter means.
I have no opportunity to
* Konstantin Malanchev [2019-07-09 11:51]:
> Hello,
>
> I'm running PostgreSQL 11.4 on Linux 4.12.14 and I see the following issue
> while executing single one query:
> ERROR: could not resize shared
> memory segment "/PostgreSQL.1596105766" to 536870912 bytes: No space left on
> device
>
> I
