Re: Mixing DBLink versions

David Jantzen <djantzen(at)ql2(dot)com> writes:
> Due to some historical idiosyncracies in our environment, we have a custom 8.3.7 database installation built from source. We'd like to install dblink into this, however there are some problems with doing so:

> 1) the 8.3.7 database was built on a CentOS 4 build box that has since gone away
> 2) currently we have only 8.3.9 code built against CentOS 5
> 3) the GCC compiler on CentOS 4 was quite old
> 4) possible API changes in dblink between those versions

> My question, how risky would it be to copy the dblink.so and .sql files from the CentOS 5 compilation of Postgres 8.3.9 over to the CentOS 4 compilation of Postgres 8.3.7? If runtime errors result, how severe would they be? I.e., would they take down a postgres backend or possibly the postmaster daemon?

I think you've got a fundamental problem that you'd better fix. If you
are unable to rebuild the database from source then you are unable to
update --- and you are already three minor versions behind and missing
multiple security and crash-risk bug fixes. You're living on borrowed
time, and NEED to reinstantiate your ability to build for that platform.
Or move to a newer one.

FWIW, you could probably get back a RHEL4 build environment pretty
cheaply by setting up a suitable "mock" chroot on a recent Fedora
version (installed on the same type of hardware).

As for your direct question: no, I wouldn't count on that to work.
RHEL4 and RHEL5 had different glibc versions didn't they?

regards, tom lane