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Hi, We are using Postgres 8.1.4 for an embedded linux device.
I have max_files_per_process unset – so it should take on the default
value of 1000. However, it appears that at times, postmaster has 1023
files open (lsof). My understanding is that if postgres exceeds this limit, it
will result in a warning message – not an error. That is, postgres
will close and re-open files if needed. Questions: -
Why is it exceeding this limit –
is this a “soft limit”? -
Is so, is there a way to set a hard
limit? (or a rule of thumb – such as if you want postgres to never exceed
1024, set to 900?) -
If at the limit, when it tries to
syslog or perform some other operation, and (or other activity), and that
operation needs to get a new fd – then presumably it could fail.
When at or near the limit can we be sure that no spurios allocation occurs? According to the postgres documentation: max_files_per_process (integer) Sets the maximum number of simultaneously
open files allowed to each server subprocess. The default is 1000. If the
kernel is enforcing a safe per-process limit, you don't need to worry about
this setting. But on some platforms (notably, most BSD systems), the kernel
will allow individual processes to open many more files than the system can
really support when a large number of processes all try to open that many
files. If you find yourself seeing "Too many open files" failures,
try reducing this setting. This option can only be set at server start. |
