| From: | "Zeugswetter Andreas SB SD" <ZeugswetterA(at)spardat(dot)at> |
|---|---|
| To: | "Tom Lane" <tgl(at)sss(dot)pgh(dot)pa(dot)us>, "Matthew Hagerty" <mhagerty(at)voyager(dot)net> |
| Cc: | "Mark Pritchard" <mark(at)tangent(dot)net(dot)au>, <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | Re: PQstatus() detect change in connection... |
| Date: | 2001-10-19 10:04:39 |
| Message-ID: | 46C15C39FEB2C44BA555E356FBCD6FA41EB3CF@m0114.s-mxs.net |
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| Lists: | pgsql-hackers |
> Matthew Hagerty <mhagerty(at)voyager(dot)net> writes:
> > but I also want to check the connection *before* submitting a
query...
If you mean directly before the query, then forget it, as Tom already
said :-)
> This strikes me as utterly pointless. You'll need to be able to
recover
> from query failure anyway, so what's the value of testing beforehand?
> Send the query and see if it works or not.
I see a value in checking connection status before you start doing
loads of local work after a long idle time, that results in a query.
In this situation I guess it is good enough to send an empty query
even if it takes a little.
In our projects we recv 0 bytes from the socket every x seconds
during long idle periods to detect connection problems early.
While it is not 100% reliable (since it does not transfer
anything over the network) it does detect some common error situations.
I am not 100% sure, but I think PQstatus could be patched to do that.
Andreas
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