Nginx access_log default flush time -

how nginx flushes buffer access_log default ?

in manual there not info, setup syntax:

access_log path [format [buffer=size [flush=time]] [if=condition]]; 

did bit of research on myself, , far can tell nginx doesn't flush buffers @ if not specify flush parameter. (or if does, it's more 20 minutes.)

the exception if restart server, logs flushed before restart.

so if specify buffer should make sure specify flush time too.