Running a multi-million row update will take a long time. It's possible you've exposed a memory leak in ST_Buffer (the older your version of GEOS, the more likely that is) but it's also possible you're just running a really long update. I find for batch processing purposes that creating fresh tables is far preferable: CREATE TABLE newtable AS SELECT ST_Buffer(geom) ... FROM oldtable; If you still see memory issues with the above then you probably do have a leak, *or* you're just running buffer on a sufficiently large input geometry or with a large enough radius to blow up the memory naturally. P On Wed, Jul 6, 2016 at 2:13 AM, Ivan Bianchi <ivan@xxxxxxxxxxx> wrote: > Hello, > > I am trying to update a column using a PostGIS ST_Buffer 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);" > > > After reading and tunning the configuration, I still have the same result. > > Here's the initial memory stats: > >> total used free shared 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. > > 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 -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
