Re: libpq thread safety

Manfred Spraul wrote:
> libpq needs additional changes for complete thread safety:
> - openssl needs different initialization.
> - kerberos is not thread safe.
> - functions such as gethostbyname are not thread safe, and could be used
> by kerberos. Right now protected with a libpq specific mutex.
> - dito for getpwuid and stderror.
>
> openssl is trivial: just proper flags are needed for the init function.
> But what about kerberos: I'm a bit reluctant to add a forth mutex: what
> if kerberos calls gethostbyname or getpwuid internally?
> Usually I would use one single_thread mutex and use that mutex for all
> operations - races are just too difficult to debug. Any better ideas?
> Otherwise I'd start searching for the non-threadsafe functions and add
> pthread_lock around them.
> Actually I'm not even sure if it should be a libpq specific mutex: what
> if the calling app needs to access openssl or kerberos as well? Perhaps
> libpq should use a system similar to openssl:
>
> http://www.openssl.org/docs/crypto/threads.html

What else needs to be done/documented?

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