postmaster.pid

Hi,

I have committed changes to postmaster.c. Now it creates a file called
"postmaster.pid" under $PGDATA, which holds postmaster's process
id. If the file has already existed, postmaster won't start. So we
cannot start more than on postmaster with same $PGDATA any more. I
believe it's a good thing. The file will be deleted upon postmaster
shutting down.

Another file "postmaster.opts" is also created under $PGDATA. It
contains the path to postmaster and each option for postmaster per
line. Example contents are shown below:

/usr/local/pgsql/bin/postmaster
-p 5432
-D /usr/local/pgsql/data
-B 64
-b /usr/local/pgsql/bin/postgres
-N 32
-S

Note that even options execpt -S is not explicitly supplied in the
case above (postmaster -S), other opts are shown. This file is not
only convenient to restart postmaster but also is usefull to determin
with what defaults postmaster is running, IMHO.

With these changes now we can stop postmaster:
kill `cat /usr/local/pgsql/data/postmaster.pid`

To restart it with previous options:
eval `cat /usr/local/pgsql/data/postmaster.opts`

I'm going to write pg_ctl script this week end.

BTW, no initdb required, of course.
--
Tatsuo Ishii