# 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
updatingmillions of rows as atomic transactions, across about 100 concurrent connections, firing the trigger for each
atomicupdate. 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
triggerto avoid using a temporary table (probably a good thing anyways) and all is well, but I was very shocked to see
Postgresbehaving badly here.
Any thoughts? And thanks for your time!
eric
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