I've been developing c-language functions in 7.4.5 and 7.4.8. I had not encountered a need to recompile, because of pg .h file, or other differences. I expected a need to do so when upgrading to 8.0.3. But I forgot to do so and it worked!! I figured I lucked out, a suspicion which was confirmed when my functions failed with 8.1beta1, but only some functions. A recompile restored correct operation under 8.1beta1. So, my question is: Is there some hard and fast rule about when one needs to recompile c-language functions from one pg version to another? Always for a major version change? minor? I suppose the wise thing is to recompile with ANY pg version change. Thanks, TJ ---------------------------(end of broadcast)--------------------------- TIP 3: Have you checked our extensive FAQ? http://www.postgresql.org/docs/faq