Bruce Momjian wrote:
> Tom Lane wrote:
> > Bruce Momjian <pgman@candle.pha.pa.us> writes:
> > > Greg Copeland wrote:
> > >> Is it possible to automate this as part of the build
> > >> process so that they get grabbed from some version information during
> > >> the build?
> >
> > > Version bump is one of the few things we do at the start of
> > > development.
> >
> > The real problem here is that major version bump (signifying an
> > incompatible API change) is something that must NOT be done in an
> > automated, mindless-checklist way. We should have executed the bump
> > when we agreed to change PQnotifies' API incompatibly. We screwed up
> > on that. I think it's correct to fix the error for 7.3.1 --- but we
> > cannot improve on the situation by making some procedural change to
> > "always do X at point Y in the release cycle". Sometimes there's
> > no substitute for actual thinking :-(
>
> Oh, a major bump. I thought we did major bumps only in cases where a
> recompile will _not_ fix the problem, like changing a parameter value to
> a function or removing a function or something like that.
That's not strictly how the major and minor numbers were intended to
be used, at least as I understand it.
The reason you really have no choice but to bump the major number in
the case of the introduction of binary incompatibilities (whether or
not a recompile would fix it) is that the dynamic linker usually uses
the major version *only* to determine which library to dynamically
link against (but see below for a caveat).
So what's the purpose of the minor version number? To indicate which
revision of the library is in use. It may be that version 2.1 has
bugfixes that 2.0 doesn't have, so the minor version number allows you
to determine whether or not you have the fixes in question.
Generally, you can specify at library build time whether an
application must link with a specific major/minor numbered library, or
whether it can link against any library with the same major number.
Most people do the latter, and that's as it should be. If the
PostgreSQL libraries (for instance) required a match against the minor
number, then applications would have to be recompiled every time
PostgreSQL was upgraded. Not only is that highly undesirable, for
some it may not even be possible (e.g., when using commercial
applications).
--
Kevin Brown kevin@sysexperts.com
