Re: psql and named pipes - Mailing list pgsql-hackers

From Aidan Van Dyk
Subject Re: psql and named pipes
Date
Msg-id 20080327170517.GR6497@yugib.highrise.ca
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In response to psql and named pipes  (Alvaro Herrera <alvherre@commandprompt.com>)
Responses Re: psql and named pipes
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* Alvaro Herrera <alvherre@commandprompt.com> [080327 12:58]:
> I was under the impression that I could start a "psql -f pipe" and then
> feed it commands through the pipe using echo, and expect it to hang from
> one command to the next.  Of course, this doesn't work -- my guess is
> that echo sends an EOF after the line I send, so psql sees the EOF in
> the pipe and terminates.
> 
> Does anyone have an idea how to go about this?  I was expecting to be
> able to drive two psql sessions in parallel in a shell script -- sort of
> poor man's concurrent psql :-(

I've had to use:while (true); do cat pipe; done | psql

The trick is that pipes "EOF"s everytime the cleint closes it.  (Not
strictly true, but it appears that way to basic read()ers).

You can see a more compilcated setup I use to echo commands to a pipe
going to a psql here:http://www.highrise.ca/aidan/postgresql/watchsql

-- 
Aidan Van Dyk                                             Create like a god,
aidan@highrise.ca                                       command like a king,
http://www.highrise.ca/                                   work like a slave.

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