Thread: pgsql: Further improvements in pg_ctl's new wait-for-postmaster-start l
Further improvements in pg_ctl's new wait-for-postmaster-start logic. Add a postmaster_is_alive() test to the wait loop, so that we stop waiting if the postmaster dies without removing its pidfile. Unfortunately this only helps after the postmaster has created its pidfile, since until then we don't know which PID to check. But if it never does create the pidfile, we can give up in a relatively short time, so this is a useful addition in practice. Per suggestion from Fujii Masao, though this doesn't look very much like his patch. In addition, improve pg_ctl's ability to cope with pre-existing pidfiles. Such a file might or might not represent a live postmaster that is going to block our postmaster from starting, but the previous code pre-judged the situation and gave up waiting immediately. Now, we will wait for up to 5 seconds to see if our postmaster overwrites such a file. This issue interacts with Fujii's patch because we would make the wrong conclusion if we did the postmaster_is_alive() test with a pre-existing PID. All of this could be improved if we rewrote start_postmaster() so that it could report the child postmaster's PID, so that we'd know a-priori the correct PID to test with postmaster_is_alive(). That looks like a bit too much change for so late in the 9.1 development cycle, unfortunately. Branch ------ master Details ------- http://git.postgresql.org/pg/commitdiff/3c485ca8e6580409284ac50623286b0fb8cd4a57 Modified Files -------------- src/bin/pg_ctl/pg_ctl.c | 168 +++++++++++++++++++++++++++-------------------- 1 files changed, 98 insertions(+), 70 deletions(-)
Re: pgsql: Further improvements in pg_ctl's new wait-for-postmaster-start l
From
Bruce Momjian
Date:
Tom Lane wrote: > All of this could be improved if we rewrote start_postmaster() so that it > could report the child postmaster's PID, so that we'd know a-priori the > correct PID to test with postmaster_is_alive(). That looks like a bit too > much change for so late in the 9.1 development cycle, unfortunately. Is this a TODO? -- Bruce Momjian <bruce@momjian.us> http://momjian.us EnterpriseDB http://enterprisedb.com + It's impossible for everything to be true. +
Bruce Momjian <bruce@momjian.us> writes: > Tom Lane wrote: >> All of this could be improved if we rewrote start_postmaster() so that it >> could report the child postmaster's PID, so that we'd know a-priori the >> correct PID to test with postmaster_is_alive(). That looks like a bit too >> much change for so late in the 9.1 development cycle, unfortunately. > Is this a TODO? Yeah, probably. Until this go-round it wasn't worth the trouble, but now it seems like the one remaining roadblock to making pg_ctl start -w fully bulletproof. regards, tom lane
Re: pgsql: Further improvements in pg_ctl's new wait-for-postmaster-start l
From
Bruce Momjian
Date:
Tom Lane wrote: > Bruce Momjian <bruce@momjian.us> writes: > > Tom Lane wrote: > >> All of this could be improved if we rewrote start_postmaster() so that it > >> could report the child postmaster's PID, so that we'd know a-priori the > >> correct PID to test with postmaster_is_alive(). That looks like a bit too > >> much change for so late in the 9.1 development cycle, unfortunately. > > > Is this a TODO? > > Yeah, probably. Until this go-round it wasn't worth the trouble, but > now it seems like the one remaining roadblock to making pg_ctl start -w > fully bulletproof. Done: Improve pg_ctl's detection of running postmasters * http://archives.postgresql.org/pgsql-hackers/2011-06/msg00000.php * http://archives.postgresql.org/pgsql-committers/2011-06/msg00001.php -- Bruce Momjian <bruce@momjian.us> http://momjian.us EnterpriseDB http://enterprisedb.com + It's impossible for everything to be true. +