| From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
|---|---|
| To: | Vamsi Patchipulusu <vpatchipulusu(at)equinix(dot)com> |
| Cc: | "pgsql-general(at)postgresql(dot)org" <pgsql-general(at)postgresql(dot)org>, Danjue Li <danli(at)equinix(dot)com>, Rashmi Panthangi <rpanthangi(at)equinix(dot)com>, Lakshmi Yarlagadda <lyarlagadda(at)equinix(dot)com> |
| Subject: | Re: Postgres intermittent connection errors: psql.bin: could not connect to server: Cannot assign requested address |
| Date: | 2017-05-16 06:29:26 |
| Message-ID: | 30038.1494916166@sss.pgh.pa.us |
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| Lists: | pgsql-general |
Vamsi Patchipulusu <vpatchipulusu(at)equinix(dot)com> writes:
> Error: psql.bin: could not connect to server: Cannot assign requested address
> Is the server running on host "abchost.corp.xyz.com" (xxx.xxx.xxx.xxx) and accepting
> TCP/IP connections on port 5432?
Googling suggests that this could occur if you're recycling client-side
connections so fast that the old port number assignments haven't timed out
yet. That's not a Postgres bug, it's inherent in the TCP protocol specs.
> The shell script does the following:
> a) Connects to postgres database server using psql.
> b) Issues a single select statement on table with 200 rows .
> c) Writes the results to a text file.
There is a large body of evidence to the effect that issuing only one
query per connection attempt is a performance-killer. Don't do that, at
least not more often than you have to. This particular symptom is a new
one on me, but there are lots of other reasons not to do it.
regards, tom lane
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