On 07/06/2016 02:13 AM, Ivan Bianchi wrote:
Hello,
I am trying to update a column using a PostGIS ST_Buffer
<http://postgis.net/docs/ST_Buffer.html> function into a table
of 4.257.769 rows, but after 6 hours, an /Out of memory/ error appears
and the kernel starts killing processes until a /Kernel Panic/ shows up.
I have simplified the buffer target geometry and also added a gist index
to that column.
The statement is the following:
psql -h host -U user -W -d database -c "UPDATE table SET buffer =
ST_Buffer(simplified_geometry, 0.005);"
I would say the issue is the above, you are running in a single
transaction. Given that an UPDATE in Postgres is a DELETE/INSERT and
that both the new and old rows have to be kept around until the
transaction completes I see only problems with doing it this way.
After reading and tunning the configuration, I still have the same result.
Here's the initial memory stats:
total used freeshared buff/cache
available
Mem: 15G 1.5G 12G 503M 1.4G
13G
Swap: 7.8G 0B 7.8G
I'm running out of ideas, as I think the postgresql.conf memory
parameters are quite low for the machine specs. I understand I can split
the process and paginate the rows, but I can't see why I can't deal with
this full statement right now.
See above.
Do you think this issue is related with the postgres memory parameters
configuration? Why is not respecting the shared_buffers or
effective_cache_size parameters and keeps growing?
Here's some info:
*
*
_Machine specs_
* Intel(R) Core(TM) i7-4790K CPU @ 4.00GHz (8 cores)
* 16 GB of memory
* Fedora release 23 (Twenty Three)
* Kernel - 4.5.7-202.fc23.x86_64
_postgresql.conf_
* effective_cache_size = 5GB
* shared_buffers = 3GB
* work_mem = 10MB
* maintenance_work_mem = 800MB
* wal_buffers = 16MB
_Kernel parameters_
* vm.overcommit_memory=2
* kernel.shmmax = 8340893696
* kernel.shmall = 2036351
_Versions:_
* PostgreSQL 9.5.3 on x86_64-pc-linux-gnu, compiled by gcc (GCC) 5.3.1
20160406 (Red Hat 5.3.1-6), 64-bit
* POSTGIS="2.2.2 r14797" GEOS="3.5.0-CAPI-1.9.0 r4084" PROJ="Rel.
4.9.1, 04 March 2015" GDAL="GDAL 2.0.2, released 2016/01/26"
LIBXML="2.9.3" LIBJSON="0.12" RASTER
Many thanks,
--
Ivan
--
Adrian Klaver
adrian.klaver@xxxxxxxxxxx
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