Re: Question and suggestion about application binary compatibility policy

> From: Michael Meskes [mailto:meskes(at)postgresql(dot)org]
> > Yes, but Windows users probably don't understand or know it. So, I
> > suggested explicitly describing the application binary compatibility
> > policy in the PostgreSQL manual. What do you think about it?
>
> Couldn't you point your customer to the system documentation?
>
> Personally I don't think standard system behavior should be documented for
> each application relying on it but ymmv.

I couldn't find appropriate system documentation. Regarding Linux, I remember I saw some HOWTO on tldp.org website which explains the concept of shared library soname, but it's not very friendly for users who just want to know the application binary compatibility policy of PostgreSQL. And I don't think there's suitable documentation on Windows. Even if there is any, users will not be sure whether PostgreSQL follows those platform-specific conventions. They may have doubts about it, because even the product version "PostgreSQL x.y.z" causes misconception that x is the major version and y is the minor one.

So, I suggested documenting the compatibility policy for clarification and user friendliness as in the Oracle Database documentation below.

http://docs.oracle.com/database/121/UPGRD/app.htm#UPGRD12547

BTW, although this may be a separate topic, it may be better that we add the major version in the library names like libpq5.dll and libecpg6.dll, so that the application can fail to run with the incompatible versions of libpq and libecpg. FYI:

https://en.wikipedia.org/wiki/Side-by-side_assembly

[Excerpt]
Microsoft Visual C++ 2005 and 2008 employ SxS with all C runtime libraries. However, runtime libraries in Visual C++ 2010 no longer use this technology; instead, they include the version number of a DLL in its file name, which means that different versions of one DLL will technically be completely different DLLs now.

Any comments on these? If there's no strong objection, I think I'll submit a documentation patch in the future.

Regards
Takayuki Tsunakawa