On Fri, Jul 1, 2016 at 9:33 AM, Tsunakawa, Takayuki <tsunakawa.ta...@jp.fujitsu.com> wrote: > [Q1] > Can the same UDF binary be used with different PostgreSQL minor releases? If > it is, is it a defined policy (e.g. written somewhere in the manual, wiki, > documentation in the source code)? > > For example, suppose you build a UDF X (some_extension.so/dll) with > PostgreSQL 9.5.0. Can I use the binary with PostgreSQL 9.5.x without > rebuilding?
Yes, that works properly. There could be problems with potential changes in the backend APIs in a stable branch, but this usually does not happen much. > Here, the UDF references the contents of server-side data structures, like > pgstattuple accesses the members of HeapScanData. If some bug fix of > PostgreSQL changes the member layout of those structures, the UDF binary > would possibly misbehave. Basically, should all UDFs be rebuilt with the new > minor release? Not necessarily. > Or, are PostgreSQL developers aware of such incompatibility and careful not > to change data structure layout? Committers are aware and careful about that, that's why exposed APIs and structures are normally kept stable. At least that's what I see. > [Q2] > Can the same UDF binary be used with different PostgreSQL distributions > (EnterpriseDB, OpenSCG, RHEL packages, etc.)? Or should the UDF be built > with the target distribution? Each distribution has usually its own compilation options (say page size, etc.) even if I recall that most of them use the defaults, so it clearly depends on what kind of things each of them uses. I would recommend a recompilation just to be safe. It may not be worth spending time at looking and checking each one's differences. > I guess the rebuild is necessary if the distribution modified the source code > of PostgreSQL. That is, the UDF binary built with the bare PostgreSQL cannot > be used with EnterpriseDB's advanced edition, which may modify various data > structures. That's for sure. > How about other distributions which probably don't modify the source code? > Should the UDF be built with the target PostgreSQL because configure options > may differ, which affects data structures? It depends on how they build it, but recompiling is the safest bet to avoid any surprises... I recall seeing an extension code that caused a SIGSEV with fclose(NULL) on SLES and only reported an error with Ubuntu. The code was faulty in this case.. But recompiling is usually a better bet of stability. -- Michael -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
