# select version();
version
-----------------------------------------------------------------------------------------------------------------------------------
PostgreSQL 9.3.4 on x86_64-apple-darwin13.2.0, compiled by Apple LLVM version
5.1 (clang-503.0.40) (based on LLVM 3.4svn), 64-bit
(1 row)
As best I can guess, Postgres has some kind of memory leak around (at least)
temporary tables flagged to drop on commit. It's fairly easy to reproduce:
Terminal A
--------------
$ createdb leak
$ for i in $(seq 1 1000000) ; do echo "begin; create temp table foo() on commit
drop; commit;"; done | psql leak > /dev/null
Terminal B
--------------
$ while(true); do ps auwx | grep $PID_OF_POSTGRES_PROCESS_FROM_TERMINAL_A;
sleep 1 ; done
And watch the RSS size continue to climb, fairly quickly. This happens on both
OS X and Linux (both x86_64).
We ran into this thanks to an update trigger that created a temporary table
with on commit drop where we were literally updating millions of rows as atomic
transactions, across about 100 concurrent connections, firing the trigger for
each atomic update. The server quickly ran out of memory.
It took some time to find what appears to be the actual problem, but I think
this is it. We've since rewritten the trigger to avoid using a temporary table
(probably a good thing anyways) and all is well, but I was very shocked to see
Postgres behaving badly here.
Any thoughts? And thanks for your time!
eric
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