Peculiar behaviour in libpq

I've noticed some strange behaviour when using libpq with
PostgreSQL 6.4.2 on RedHat Linux 5.1. I'm using libpq asynchronously, with
a select() loop, calling PQconsumeInput etc. What is happening is that
occasionally, after I have received a callback via select() and processed
the result, I get an extra callback. These extra callbacks have no result
attached to them, PQisBusy() returns false, and, by the records I'm
keeping in my own program, there is no database operation pending (ie I
already have a result for every operation I've submitted).

I guess it's some sort of random noise on the socket or something. Or
maybe the backend just sends a nothing-in-particular packet down the line
every now and then. But I'm wondering if this is a symptom of something
else going wrong.

It tends to happen after several other operations, ie while the database
is reasonably busy, not when it's idle.

Has anyone else ever seen this behaviour? Is it anything to worry about?
Will it go away in 6.5? On the whole it seems reasonably benign, I just
worry there may be something bad going on that will bite me eventually.

Tim

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Tim Allen
Proximity Pty Ltd  http://www.proximity.com.au
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