Re: PostgreSQL libraries - PThread Support, but not use...

Lee Kindness <lkindness(at)csl(dot)co(dot)uk> writes:
> On a slightly related note to the other threads thread [sic] going
> on... Over the Christmas/New Year break i've been looking into making
> the PostgreSQL client libraries (in particular libpq and ecpg)
> thread-safe - that is they can safely be used by a program which
> itself is using mutliple threads. I'm largely there with ecpg (globals
> are protected, a sqlca for each thread), but of course it relies on
> libpq which needs work to share a connection between thrreads.

AFAIK, libpq is thread-safe already, it's just not thread-aware.
What you'd presumably want is a wrapper layer that adds a mutex to
prevent multiple threads from manipulating a PGconn at the same time.
Couldn't this be done without touching libpq at all?

> 1. It's looking likely that the libraries will need to link to
> libpthread, and as a result anything linking to the libraries will
> need to link to libpthread too. Will this be accepted in a patch?

If the patch requires pthread and not any other form of thread support,
probably not. See nearby threading thread ;-)

In general I'd be unhappy with doing anything to libpq that forces
non-threaded clients to start depending on libpthread (or other thread
libraries). Thus the idea of a wrapper seems more appealing to me.

regards, tom lane