Re: pg_ctl reports succes when start fails - Mailing list pgsql-hackers

From Andrew Dunstan
Subject Re: pg_ctl reports succes when start fails
Date
Msg-id 3F9934C5.2020104@dunslane.net
Whole thread Raw
In response to Re: pg_ctl reports succes when start fails  (Peter Eisentraut <peter_e@gmx.net>)
Responses Re: pg_ctl reports succes when start fails
List pgsql-hackers
Peter Eisentraut wrote:

>Tom Lane writes:
>
>  
>
>>I also wonder why -w isn't the default.
>>    
>>
>
>Because it is not sufficiently reliable in start mode.  See
>source code and archives.
>
>  
>

I think we can improve -w, though. Here's what the code says about the 
section where it tries to use psql to determine that the postmaster is 
up and running:

# FIXME:  This is horribly misconceived.
# 1) If password authentication is set up, the connection will fail.
# 2) If a virtual host is set up, the connection may fail.
# 3) If network traffic filters are set up tight enough, the connection
#    may fail.
# 4) When no Unix domain sockets are available, the connection will
#    fail.  (Using TCP/IP by default ain't better.)
# 5) If the dynamic loader is not set up correctly (for this user/at
#    this time), psql will fail (to find libpq).
# 6) If psql is misconfigured, this may fail.

we could provide a password option to handle 1, and in C we can make the 
connection ourselves using libpq instead of relying on psql to do it for 
us, which should account for 5 and 6, I think.

For the cases of 2, 3 and 4 we can either try to detect it from the 
configuration settings, or suggest that users will need to use -W for 
such cases. To me it would be strange to have a setup where no 
connection from the machine where pg is running is possible, but maybe 
people do such odd things.

We can also try to come up with a better scheme for verifying that we 
have started properly - I will think about that.

cheers

andrew







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