I'm starting up postgresql with this command line:
/usr/bin/setpgrp ${POSTGRESQL_HOME}/bin/pg_ctl -w -o "-i" start
...and there are two things about this that raise a question. First, we
use the setpgrp because, although pg_ctl documentation (7.3.4) states
that it can be used for "properly detaching from the terminal and
process group", we have not found this to work as expected. In
particular, when a ctl-C is issued from the same tty as was used for the
pg_ctl command (without the setpgrp), the associated postmaster
processes are killed (with a fast shutdown, i.e. they receive the SIGINT
signal from the ctl-C). Prefacing pg_ctl with setpgrp addresses this
problem for us. So, the first question would be, what am I not
understanding here?
More importantly, we want to start up the database "completely" before
any client connections are attempted. This matters to us in our
build/test environment where we have complete control over client
connections; we're only trying to be certain the database is ready
before launching a series of builds/tests that don't initialize properly
due to the "FATAL: The database system is starting up" messages, which
are received on each attempted client connection, and wasting a whole
build-test cycle as a result. According the pg_ctl documentation again,
we're told that the -w flag will cause pg_ctl to "Wait for the start or
shutdown to complete", and we hoped this would effectively cause pg_ctl
to block until the database startup is "complete"; however this too does
not work as expected. We are testing for "startup-is-complete" with the
following:
until ${POSTGRESQL_HOME}/bin/psql -l > /dev/null 2>&1 ||
${POSTGRESQL_HOME}/bin/psql -l -d template1 -U $PORTAL_DB_OWNER
...and it happens that /sometimes/ this test succeeds and yet subsequent
client connections fail due to the "FATAL: The database system is
starting up" condition.
From this, a whole series of questions comes up in my mind:
- is this the proper idiom to test for database startup being "complete"
(i.e. "complete" means that the "FATAL: The database system is starting
up" error messages should not occur)?
- If not, what test should we be using instead?
- If so, what could be happening here?
- is there a better way to start up postresql to achieve what we want?
- is setpgrp somehow getting in the way of the -w flag working as desired?
Thanks for any insights -
Gary Horton
