Обсуждение: PQnotifies() in 7.3 broken?
Thanks to Rod Taylor's kind help in donating a system account, I've been able to test libpqxx against postgres 7.3. Unfortunately, I'm running into several problems. One thing that broke libpqxx was a change in cursor behaviour that according to Sigurdur Gunnlaugsson seems to be gone in the 7.4 development tree. But I'm hitting other snags as well. When receiving a trigger notification under 7.3, the structure returned by PQnotifies() appears to be bogus. In a test I ran, its be_pid was consistently zero and its relname pointed into never-neverland. Has anyone else come across this? Jeroen
"Jeroen T. Vermeulen" <jtv@xs4all.nl> writes:
> When receiving a trigger notification under 7.3, the structure returned
> by PQnotifies() appears to be bogus. In a test I ran, its be_pid was
> consistently zero and its relname pointed into never-neverland.
We changed the PQnotifies result structure in 7.3 (to insulate clients
from the value of NAMEDATALEN). I think you are compiling your app with
a 7.3 libpq header and then running it with 7.2 libpq code, or possibly
vice versa.
regards, tom lane
Perhaps the .so name should have been updated for PostgreSQL 7.3? For example in 7.2 libpq is: /usr/lib/libpq.so -> libpq.so.2.2 /usr/lib/libpq.so.2 -> libpq.so.2.2 /usr/lib/libpq.so.2.0 -> libpq.so.2 /usr/lib/libpq.so.2.2 and PostgreSQL 7.3: /usr/lib/libpq.so -> libpq.so.2.2 /usr/lib/libpq.so.2 -> libpq.so.2.2 /usr/lib/libpq.so.2.0 -> libpq.so.2 /usr/lib/libpq.so.2.2 the same. This would seem to imply binary compatibility? Lee. Tom Lane writes:> "Jeroen T. Vermeulen" <jtv@xs4all.nl> writes:> > When receiving a trigger notification under 7.3, the structurereturned> > by PQnotifies() appears to be bogus. In a test I ran, its be_pid was> > consistently zero and its relnamepointed into never-neverland.> We changed the PQnotifies result structure in 7.3 (to insulate clients> from the valueof NAMEDATALEN). I think you are compiling your app with> a 7.3 libpq header and then running it with 7.2 libpq code,or possibly> vice versa.
Lee Kindness <lkindness@csl.co.uk> writes:
> Perhaps the .so name should have been updated for PostgreSQL 7.3?
It should have been. If it wasn't, that was a serious oversight.
Not sure if we should change it in 7.3.1 or not, though; it may be
too late for that. Any thoughts out there?
regards, tom lane
Tom Lane wrote: > Lee Kindness <lkindness@csl.co.uk> writes: > > Perhaps the .so name should have been updated for PostgreSQL 7.3? > > It should have been. If it wasn't, that was a serious oversight. > Not sure if we should change it in 7.3.1 or not, though; it may be > too late for that. Any thoughts out there? Seems I did forget. I always update the minor for a major release, but when development starts, and I seem to have forgotten for 7.3. Sorry. I will update for 7.4 now. Too late for 7.3 clearly. Turns out I usually do it when I stamp the new development tree, but someone else stamped 7.3 and 7.4. :-( Here is 7.2 stamp, which shows the updates:revision 1.52date: 2001/05/11 01:46:33; author: momjian; state: Exp; lines:+2 -2Stamp CVS as 7.2. Update all interface version numbers. This is thetime to do it, not during beta because peopleare using this stuff inproduction sometimes. The diff shows:****************** 15,21 **** # shared library parameters NAME= pq SO_MAJOR_VERSION= 2! SO_MINOR_VERSION=1 override CPPFLAGS := -I$(srcdir) $(CPPFLAGS) -DFRONTEND-DSYSCONFDIR='"$(sysconfdir)"' --- 15,21 ---- # shared library parameters NAME= pq SO_MAJOR_VERSION= 2! SO_MINOR_VERSION= 2 so clearly 7.2 and 7.3 have the same minor version for all interfaces. Bad! -- Bruce Momjian | http://candle.pha.pa.us pgman@candle.pha.pa.us | (610) 359-1001+ If your life is a hard drive, | 13 Roberts Road + Christ can be your backup. | Newtown Square, Pennsylvania19073
Bruce Momjian writes: > so clearly 7.2 and 7.3 have the same minor version for all interfaces. Bad! We forgot between 7.0 and 7.1 as well, so it's at least consistent... -- Peter Eisentraut peter_e@gmx.net
Peter Eisentraut wrote: > Bruce Momjian writes: > > > so clearly 7.2 and 7.3 have the same minor version for all interfaces. Bad! > > We forgot between 7.0 and 7.1 as well, so it's at least consistent... Yes, seems we increament on every even-numbered release. ;-) -- Bruce Momjian | http://candle.pha.pa.us pgman@candle.pha.pa.us | (610) 359-1001+ If your life is a hard drive, | 13 Roberts Road + Christ can be your backup. | Newtown Square, Pennsylvania19073
On Wed, 2002-12-04 at 13:11, Bruce Momjian wrote: > Seems I did forget. I always update the minor for a major release, but > when development starts, and I seem to have forgotten for 7.3. Sorry. > > I will update for 7.4 now. Too late for 7.3 clearly. Wouldn't that suggest that libpq in 7.4 and 7.3 are *not* binary compatible? AFAIK that's not the case... Cheers, Neil -- Neil Conway <neilc@samurai.com> || PGP Key ID: DB3C29FC
Neil Conway wrote: > On Wed, 2002-12-04 at 13:11, Bruce Momjian wrote: > > Seems I did forget. I always update the minor for a major release, but > > when development starts, and I seem to have forgotten for 7.3. Sorry. > > > > I will update for 7.4 now. Too late for 7.3 clearly. > > Wouldn't that suggest that libpq in 7.4 and 7.3 are *not* binary > compatible? AFAIK that's not the case... I updated the _minor_ version number, which doesn't affect binary compatibility, I think. It only makes the newer one more visible. -- Bruce Momjian | http://candle.pha.pa.us pgman@candle.pha.pa.us | (610) 359-1001+ If your life is a hard drive, | 13 Roberts Road + Christ can be your backup. | Newtown Square, Pennsylvania19073
Bruce Momjian writes:> Tom Lane wrote:> > Lee Kindness <lkindness@csl.co.uk> writes:> > > Perhaps the .so name should havebeen updated for PostgreSQL 7.3?> > > > It should have been. If it wasn't, that was a serious oversight.> > Not sureif we should change it in 7.3.1 or not, though; it may be> > too late for that. Any thoughts out there?> Seems I didforget. I always update the minor for a major release, but> when development starts, and I seem to have forgotten for7.3. Sorry. Personally I think automatically updating the version numbers is as bad as not doing it at all - it misses the point. The version numbers in shared library filenames denote binary compatibilty, if the /public/ API changes then the version number really must be incremented. If the version increments without any associated API changes then it's just a PITA for developers and products linking to the PostgreSQL libraries! It forces recompilation when there is not really a need. Lee.
Lee Kindness wrote: > Bruce Momjian writes: > > Tom Lane wrote: > > > Lee Kindness <lkindness@csl.co.uk> writes: > > > > Perhaps the .so name should have been updated for PostgreSQL 7.3? > > > > > > It should have been. If it wasn't, that was a serious oversight. > > > Not sure if we should change it in 7.3.1 or not, though; it may be > > > too late for that. Any thoughts out there? > > Seems I did forget. I always update the minor for a major release, but > > when development starts, and I seem to have forgotten for 7.3. Sorry. > > Personally I think automatically updating the version numbers is as > bad as not doing it at all - it misses the point. > > The version numbers in shared library filenames denote binary > compatibilty, if the /public/ API changes then the version number > really must be incremented. > > If the version increments without any associated API changes then it's > just a PITA for developers and products linking to the PostgreSQL > libraries! It forces recompilation when there is not really a need. It is my understanding that only the major number force recompliation. We came up with this procedure after quite a bit of discussion. I am happy to change it, but I need more than one person to tell me that. -- Bruce Momjian | http://candle.pha.pa.us pgman@candle.pha.pa.us | (610) 359-1001+ If your life is a hard drive, | 13 Roberts Road + Christ can be your backup. | Newtown Square, Pennsylvania19073
Bruce Momjian wrote: > > I will update for 7.4 now. Too late for 7.3 clearly. > Bruce, why is it too late? Most (all) will upgrade to 7.3.1 anyway, so it is a chance to get things right. -- Fernando Nasser Red Hat - Toronto E-Mail: fnasser@redhat.com 2323 Yonge Street, Suite #300 Toronto, Ontario M4P 2C9
Fernando Nasser wrote: > Bruce Momjian wrote: > > > > I will update for 7.4 now. Too late for 7.3 clearly. > > > > Bruce, why is it too late? > > Most (all) will upgrade to 7.3.1 anyway, so it is a chance to get things right. Oh. yes. Is it safe to do that? -- Bruce Momjian | http://candle.pha.pa.us pgman@candle.pha.pa.us | (610) 359-1001+ If your life is a hard drive, | 13 Roberts Road + Christ can be your backup. | Newtown Square, Pennsylvania19073
Bruce Momjian <pgman@candle.pha.pa.us> writes:
> Fernando Nasser wrote:
>> Bruce Momjian wrote:
>> Bruce, why is it too late?
>>
>> Most (all) will upgrade to 7.3.1 anyway, so it is a chance to get things right.
> Oh. yes. Is it safe to do that?
The RPM packagers should probably have a say in this, but I'm leaning
to agree with Fernando. The bulk of our users probably will not update
from 7.2.* to 7.3 before 7.3.1 is out (at least not for production),
so the fact that 7.3 has the wrong library version number won't affect
them. But people will continue to get burnt if we don't fix it for
7.3.1.
It is not real clear to me whether we need a major version bump, rather
than a minor one. We *do* need to signal binary incompatibility. Who
can clarify the rules here?
regards, tom lane
On Thu, Dec 05, 2002 at 03:27:23PM -0500, Tom Lane wrote: > > It is not real clear to me whether we need a major version bump, rather > than a minor one. We *do* need to signal binary incompatibility. Who > can clarify the rules here? One thing I wonder about: should the rules make any distinction between API incompatibilities and client protocol incompatibilities? For the former I would imagine one would like to have some "minor" version number increase whenever features are added and a "major" number be incremented when changes become incompatible. For the former, one would probably want to have a similar rule but with a dichotomy between server-side upgrades and client-side upgrades. Jeroen
Jeroen T. Vermeulen wrote: > On Thu, Dec 05, 2002 at 03:27:23PM -0500, Tom Lane wrote: > > > > It is not real clear to me whether we need a major version bump, rather > > than a minor one. We *do* need to signal binary incompatibility. Who > > can clarify the rules here? > > One thing I wonder about: should the rules make any distinction between > API incompatibilities and client protocol incompatibilities? For the > former I would imagine one would like to have some "minor" version number > increase whenever features are added and a "major" number be incremented > when changes become incompatible. For the former, one would probably > want to have a similar rule but with a dichotomy between server-side > upgrades and client-side upgrades. Yes, now that I remember, that was the big distinction. One requires a recompile, the other one doesn't even work with a newer db. -- Bruce Momjian | http://candle.pha.pa.us pgman@candle.pha.pa.us | (610) 359-1001+ If your life is a hard drive, | 13 Roberts Road + Christ can be your backup. | Newtown Square, Pennsylvania19073
Tom Lane writes: > It is not real clear to me whether we need a major version bump, rather > than a minor one. We *do* need to signal binary incompatibility. Who > can clarify the rules here? Strictly speaking, it's platform-dependent, but our shared library code plays a bit of abuse with it. What it comes down to is: If you change or remove an interface, increment the major version number. If you add an interface, increment the minor version number. If you did neither but changed the source code at all, increment the third version number, if we had one. To be thoroughly amused, read the libtool source. Grep for 'version_type'. -- Peter Eisentraut peter_e@gmx.net
Peter Eisentraut wrote: > Tom Lane writes: > > > It is not real clear to me whether we need a major version bump, rather > > than a minor one. We *do* need to signal binary incompatibility. Who > > can clarify the rules here? > > Strictly speaking, it's platform-dependent, but our shared library code > plays a bit of abuse with it. What it comes down to is: > > If you change or remove an interface, increment the major version number. > If you add an interface, increment the minor version number. If you did > neither but changed the source code at all, increment the third version > number, if we had one. My take on it is: if you break binary compatibility, which includes semantic dependencies, then you increment the major version number. Otherwise you increment the minor version number. Since the change we're talking about apparently broke binary compatibility, it calls for a major version number change. Protocol incompatibility requires a different method of enforcement altogether. Incrementing the major number of the library isn't going to do you any good for that (7.2 clients on remote systems won't have any idea that the libraries on the 7.3 server have changed that much). All MHO, of course... -- Kevin Brown kevin@sysexperts.com This is your .signature virus: < begin 644 .signature (9V]T8VAA(0K0z end > This is your .signature virus on drugs: <> Any questions?
OK, seeing that we don't have a third number, do people want me to increment the interface numbers for 7.3.1, or just wait for the increment in 7.4? --------------------------------------------------------------------------- Peter Eisentraut wrote: > Tom Lane writes: > > > It is not real clear to me whether we need a major version bump, rather > > than a minor one. We *do* need to signal binary incompatibility. Who > > can clarify the rules here? > > Strictly speaking, it's platform-dependent, but our shared library code > plays a bit of abuse with it. What it comes down to is: > > If you change or remove an interface, increment the major version number. > If you add an interface, increment the minor version number. If you did > neither but changed the source code at all, increment the third version > number, if we had one. > > To be thoroughly amused, read the libtool source. Grep for 'version_type'. > > -- > Peter Eisentraut peter_e@gmx.net > > -- Bruce Momjian | http://candle.pha.pa.us pgman@candle.pha.pa.us | (610) 359-1001+ If your life is a hard drive, | 13 Roberts Road + Christ can be your backup. | Newtown Square, Pennsylvania19073
At 06:36 PM 10/12/2002 -0500, Bruce Momjian wrote: >do people want me to >increment the interface numbers for 7.3.1 I'd like it because I have to support & build against multiple versions. ---------------------------------------------------------------- Philip Warner | __---_____ Albatross Consulting Pty. Ltd. |----/ - \ (A.B.N. 75 008 659 498) | /(@) ______---_ Tel: (+61) 0500 83 82 81 | _________ \ Fax: (+61) 03 5330 3172 | ___________ | Http://www.rhyme.com.au | / \| | --________-- PGP key available upon request, | / and from pgp5.ai.mit.edu:11371 |/
Seems like a mistake was made. Let's (don't ya love how that sounds like I'm actually involved in the fix? ;) fix it sooner rather than later. Just curious, after a release, how come the numbers are not automatically bumped to ensure this type thing gets caught sooner rather than later? Is it possible to automate this as part of the build process so that they get grabbed from some version information during the build? Greg On Tue, 2002-12-10 at 17:36, Bruce Momjian wrote: > OK, seeing that we don't have a third number, do people want me to > increment the interface numbers for 7.3.1, or just wait for the > increment in 7.4? > > --------------------------------------------------------------------------- > > Peter Eisentraut wrote: > > Tom Lane writes: > > > > > It is not real clear to me whether we need a major version bump, rather > > > than a minor one. We *do* need to signal binary incompatibility. Who > > > can clarify the rules here? > > > > Strictly speaking, it's platform-dependent, but our shared library code > > plays a bit of abuse with it. What it comes down to is: > > > > If you change or remove an interface, increment the major version number. > > If you add an interface, increment the minor version number. If you did > > neither but changed the source code at all, increment the third version > > number, if we had one. > > > > To be thoroughly amused, read the libtool source. Grep for 'version_type'. > > > > -- > > Peter Eisentraut peter_e@gmx.net > > > > -- Greg Copeland <greg@copelandconsulting.net> Copeland Computer Consulting
Greg Copeland wrote: > Seems like a mistake was made. Let's (don't ya love how that sounds > like I'm actually involved in the fix? ;) fix it sooner rather than > later. > > Just curious, after a release, how come the numbers are not > automatically bumped to ensure this type thing gets caught sooner rather > than later? 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. For 7.2, I didn't actually stamp the 7.2 release so I never bumped them, or I forgot. Seems I also forgot for 7.1. It is listed in tools/RELEASE_CHANGES so it is just a matter of following that file. -- Bruce Momjian | http://candle.pha.pa.us pgman@candle.pha.pa.us | (610) 359-1001+ If your life is a hard drive, | 13 Roberts Road + Christ can be your backup. | Newtown Square, Pennsylvania19073
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 :-(
regards, tom lane
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. -- Bruce Momjian | http://candle.pha.pa.us pgman@candle.pha.pa.us | (610) 359-1001+ If your life is a hard drive, | 13 Roberts Road + Christ can be your backup. | Newtown Square, Pennsylvania19073
I have bumped minor versions for 7.3 and 7.4. If we decide to do something different later, fine, but this way we will not forget to have some update for 7.3. --------------------------------------------------------------------------- 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. > > -- > Bruce Momjian | http://candle.pha.pa.us > pgman@candle.pha.pa.us | (610) 359-1001 > + If your life is a hard drive, | 13 Roberts Road > + Christ can be your backup. | Newtown Square, Pennsylvania 19073 > > ---------------------------(end of broadcast)--------------------------- > TIP 5: Have you checked our extensive FAQ? > > http://www.postgresql.org/users-lounge/docs/faq.html > -- Bruce Momjian | http://candle.pha.pa.us pgman@candle.pha.pa.us | (610) 359-1001+ If your life is a hard drive, | 13 Roberts Road + Christ can be your backup. | Newtown Square, Pennsylvania19073
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
Bruce Momjian writes: > OK, seeing that we don't have a third number, do people want me to > increment the interface numbers for 7.3.1, or just wait for the > increment in 7.4? ISTM that the briefly established strategy to bump the version numbers at the beginning of development is not satisfactory. The reason is that the "beginning" is in many cases not well-defined. Example 1: If we hadn't noticed the PQnotifies() problem that started this thread we would have forgotten again. Example 2: If someone put a fix of some sort in libpq for 7.3.1, we would surely forget to bump the version number. Consequence: The library version number must be bumped as part of the release preparation, as is in fact written down in the release checklist. And such a bump should be done only after reviewing the change history of the library during that development cycle to determine if a major bump is necessary or if in fact no change at all is warranted. As for what to do right now, if others agree I would suggest that we do the appropriate version number adjustments (as described in the previous paragraph) for 7.3.1. -- Peter Eisentraut peter_e@gmx.net
Peter Eisentraut wrote: > Bruce Momjian writes: > > > OK, seeing that we don't have a third number, do people want me to > > increment the interface numbers for 7.3.1, or just wait for the > > increment in 7.4? > > ISTM that the briefly established strategy to bump the version numbers at > the beginning of development is not satisfactory. The reason is that the We bump at the beginning only because we _know_ we want new users to use the newer library. (Does the runtime linker know to get the highest minor numbered library with the same major number?) Bumping at the end is done only when we know there is some change. The big question is whether a change in the API or a change in the code (recompile) is enough to bump that major version number. We always make some force-recompile change in the library in each release, don't we? Do we just bump the major in every major release? > "beginning" is in many cases not well-defined. Example 1: If we hadn't > noticed the PQnotifies() problem that started this thread we would have > forgotten again. Example 2: If someone put a fix of some sort in libpq > for 7.3.1, we would surely forget to bump the version number. > > Consequence: The library version number must be bumped as part of the > release preparation, as is in fact written down in the release checklist. I usually bumped the minor at the beginning because this allows beta testers to not have _extra_ versions of the library laying around, and also because we make minor library changes often during beta, so it isn't clear when to bump that number. -- Bruce Momjian | http://candle.pha.pa.us pgman@candle.pha.pa.us | (610) 359-1001+ If your life is a hard drive, | 13 Roberts Road + Christ can be your backup. | Newtown Square, Pennsylvania19073
Bruce Momjian wrote: > We bump at the beginning only because we _know_ we want new users to use > the newer library. (Does the runtime linker know to get the highest > minor numbered library with the same major number?) It probably depends on the system, but the runtime linker isn't that smart under Linux. It looks for a match for the major version only, so for instance in the case of libpq major version 2, it'll look for libpq.so.2 in the library search path. Multiple minor versions of the library are managed via symlinks under Linux (libpq.so.2 -> libpq.so.2.2, for instance). > Bumping at the end is done only when we know there is some change. The > big question is whether a change in the API or a change in the code > (recompile) is enough to bump that major version number. We always make > some force-recompile change in the library in each release, don't we? > Do we just bump the major in every major release? It wouldn't be a terribly bad idea to do that, but the main criteria for bumping the major version should be binary compatibility. If applications which link against libpq.so.2 reside on the system and libpq.so.2.3 has binary incompatibilities with libpq.so.2.2, then installing libpq.so.2.3 on the system will break all the binaries that use libpq.so.2. That's why it's important to bump the major version when there are binary incompatibilities: you can install libpq.so.3 and all the while, applications that rely on libpq.so.2 will still run (because you can have both of those library versions installed on the system at the same time without conflict). > I usually bumped the minor at the beginning because this allows beta > testers to not have _extra_ versions of the library laying around, and > also because we make minor library changes often during beta, so it > isn't clear when to bump that number. I think it makes sense to change the minor number whenever there are code changes to the library that don't introduce binary incompatibilities. Whether you bump the minor version during a new release when there are no changes to the library itself is probably a matter of preference only. It doesn't really hurt anything and may make management of the version number easier. -- Kevin Brown kevin@sysexperts.com
Kevin Brown wrote: > It wouldn't be a terribly bad idea to do that, but the main criteria > for bumping the major version should be binary compatibility. If > applications which link against libpq.so.2 reside on the system and > libpq.so.2.3 has binary incompatibilities with libpq.so.2.2, then > installing libpq.so.2.3 on the system will break all the binaries that > use libpq.so.2. That's why it's important to bump the major version > when there are binary incompatibilities: you can install libpq.so.3 > and all the while, applications that rely on libpq.so.2 will still run > (because you can have both of those library versions installed on the > system at the same time without conflict). > > > I usually bumped the minor at the beginning because this allows beta > > testers to not have _extra_ versions of the library laying around, and > > also because we make minor library changes often during beta, so it > > isn't clear when to bump that number. > > I think it makes sense to change the minor number whenever there are > code changes to the library that don't introduce binary > incompatibilities. Whether you bump the minor version during a new > release when there are no changes to the library itself is probably a > matter of preference only. It doesn't really hurt anything and may > make management of the version number easier. If it is true that the linker only matches the major number, what value is there in incrementing the minor number, as we have done in the past? -- Bruce Momjian | http://candle.pha.pa.us pgman@candle.pha.pa.us | (610) 359-1001+ If your life is a hard drive, | 13 Roberts Road + Christ can be your backup. | Newtown Square, Pennsylvania19073
Bruce Momjian wrote: > If it is true that the linker only matches the major number, what value > is there in incrementing the minor number, as we have done in the > past? It's main value is in indicating to the system administrator which version of the library he has. This is particularly useful in the face of security updates. A library can have bugfixes (even significant ones) and still be binary compatible with a previous revision. Situations like that are what the minor number is useful for. It can make the developer's (or administrator's) life a little easier, since it means he can have multiple minor revisions installed on his system and change the major revision symlink to point to whichever one he wishes to actually use (given the way the dynamic linker works, the administrator can name the actual target of the symlink whatever he wishes so it's not mandatory that the developers do that for him...it just makes his life easier). I probably should have gone into a little more detail about how the linker does its thing: it looks for a literal match for what the application says it was compiled against. When the application was linked, if the library it was linked against said it was 'libpg.so.2' (As far as I know, the compile-time linker retrieves this from the library's header information, not from its filename), then that's what gets stored in the application's executable header and is what the runtime linker looks for. libpg.so.2 may be a symlink to (e.g.) libpg.so.2.1 or a hard link, or a copy of a library for that matter. The runtime linker will successfully link the shared library into the program's memory image in any of those cases -- it only has to find a shared library whose filename is the same as what's requested *and* whose header information provides the same name. -- Kevin Brown kevin@sysexperts.com
Bruce Momjian writes: > We bump at the beginning only because we _know_ we want new users to use > the newer library. (Does the runtime linker know to get the highest > minor numbered library with the same major number?) No, the run-time linker only looks at the major version. > Bumping at the end is done only when we know there is some change. That is the theory. But the practice is that we should, as you suggest, reconsider the issue at the end but we don't because we all think we already did it at the beginning. That considerably confuses the issue for no real gain. During the development cycle the version number is pretty irrelevant because it is more likely that the code is broken than that there is a genuine library conflict that could be usefully resolved. > The big question is whether a change in the API or a change in the code > (recompile) is enough to bump that major version number. We always make > some force-recompile change in the library in each release, don't we? > Do we just bump the major in every major release? The rules are pretty clear: If you change or remove an interface (= part of the API) then you change the major, if you add an interface or "improve" the code, change the minor. Whether we actually change the code during a release cycle is something that is best determined *after* the release cycle. Possibly we always do, but I wouldn't be surprised if some library like pgeasy lay dormant for a while. > I usually bumped the minor at the beginning because this allows beta > testers to not have _extra_ versions of the library laying around, and That doesn't make sense to me. Which extra versions? -- Peter Eisentraut peter_e@gmx.net
Peter Eisentraut wrote: > Bruce Momjian writes: > > > We bump at the beginning only because we _know_ we want new users to use > > the newer library. (Does the runtime linker know to get the highest > > minor numbered library with the same major number?) > > No, the run-time linker only looks at the major version. Then what value is there to incrementing the minor number? > > The big question is whether a change in the API or a change in the code > > (recompile) is enough to bump that major version number. We always make > > some force-recompile change in the library in each release, don't we? > > Do we just bump the major in every major release? > > The rules are pretty clear: If you change or remove an interface (= part > of the API) then you change the major, if you add an interface or > "improve" the code, change the minor. Whether we actually change the code So if a recompile fixes it, increment minor, else major. Then we normally only do minor-level changes,. and frankly we improve the code all during development time and during beta, so it seems pretty abitrary when we increment the minor unless we want to increment it many times during development, _or_ right before final to ensure that final releaase users have the newest version. > during a release cycle is something that is best determined *after* the > release cycle. Possibly we always do, but I wouldn't be surprised if some > library like pgeasy lay dormant for a while. > > > I usually bumped the minor at the beginning because this allows beta > > testers to not have _extra_ versions of the library laying around, and > > That doesn't make sense to me. Which extra versions? If you bump during beta, and don't delete your pgsql/ directory, you will have the old libpq.so there and the new one because once you bump the version, the old one just says in the directory. -- Bruce Momjian | http://candle.pha.pa.us pgman@candle.pha.pa.us | (610) 359-1001+ If your life is a hard drive, | 13 Roberts Road + Christ can be your backup. | Newtown Square, Pennsylvania19073
Bruce Momjian <pgman@candle.pha.pa.us> writes:
> So if a recompile fixes it, increment minor, else major.
Wrong --- if you need a recompile then it's not binary-compatible, so
it should be a major version bump.
> Then we
> normally only do minor-level changes,. and frankly we improve the code
> all during development time and during beta, so it seems pretty abitrary
> when we increment the minor unless we want to increment it many times
> during development, _or_ right before final to ensure that final
> releaase users have the newest version.
I think there is definite value in incrementing the minor version once
at the start of the cycle. Whether we do it at start or end does not
matter to end users, but it *does* help developers, who can then easily
tell whether they are looking at a devel library or the previous
release.
If we make a non-binary-compatible change during a development cycle,
we should then immediately bump the major version number. Leaving it
till the end of the cycle is an excellent recipe for forgetting, as
indeed we just did.
regards, tom lane
Tom Lane wrote: > Bruce Momjian <pgman@candle.pha.pa.us> writes: > > So if a recompile fixes it, increment minor, else major. > > Wrong --- if you need a recompile then it's not binary-compatible, so > it should be a major version bump. But the previous poster said only API changes were reasons to bump the major, right? > -- Bruce Momjian | http://candle.pha.pa.us pgman@candle.pha.pa.us | (610) 359-1001+ If your life is a hard drive, | 13 Roberts Road + Christ can be your backup. | Newtown Square, Pennsylvania19073
Bruce Momjian <pgman@candle.pha.pa.us> writes:
> Tom Lane wrote:
>> Wrong --- if you need a recompile then it's not binary-compatible, so
>> it should be a major version bump.
> But the previous poster said only API changes were reasons to bump the
> major, right?
Yes. He meant *binary* API changes, though, ie, anything that would
break extant executables originally linked to the prior version of the
shared library.
regards, tom lane
Tom Lane wrote: > Bruce Momjian <pgman@candle.pha.pa.us> writes: > > Tom Lane wrote: > >> Wrong --- if you need a recompile then it's not binary-compatible, so > >> it should be a major version bump. > > > But the previous poster said only API changes were reasons to bump the > > major, right? > > Yes. He meant *binary* API changes, though, ie, anything that would > break extant executables originally linked to the prior version of the > shared library. Just for clarification --- don't most/all our releases make a binary change that needs are compile? Actually, you are saying a recompile of the client, right? Yes, we do those rarely, and in 7.3, for the NOTIFY structure change. What we do often is want old binaries to use our new libraries. That isn't a major bump requirement, right? -- Bruce Momjian | http://candle.pha.pa.us pgman@candle.pha.pa.us | (610) 359-1001+ If your life is a hard drive, | 13 Roberts Road + Christ can be your backup. | Newtown Square, Pennsylvania19073
Bruce Momjian <pgman@candle.pha.pa.us> writes:
> Just for clarification --- don't most/all our releases make a binary
> change that needs are compile?
No, they usually don't. Adding new routines, for example, does not
break existing clients.
> What we do often is want old binaries to use our new
> libraries. That isn't a major bump requirement, right?
Exactly. A major bump means that they can't use it.
regards, tom lane
OK, so what do we do with 7.3.1. Increment major or minor? --------------------------------------------------------------------------- pgman wrote: > Tom Lane wrote: > > Bruce Momjian <pgman@candle.pha.pa.us> writes: > > > Tom Lane wrote: > > >> Wrong --- if you need a recompile then it's not binary-compatible, so > > >> it should be a major version bump. > > > > > But the previous poster said only API changes were reasons to bump the > > > major, right? > > > > Yes. He meant *binary* API changes, though, ie, anything that would > > break extant executables originally linked to the prior version of the > > shared library. > > Just for clarification --- don't most/all our releases make a binary > change that needs are compile? Actually, you are saying a recompile of > the client, right? Yes, we do those rarely, and in 7.3, for the NOTIFY > structure change. What we do often is want old binaries to use our new > libraries. That isn't a major bump requirement, right? > > -- > Bruce Momjian | http://candle.pha.pa.us > pgman@candle.pha.pa.us | (610) 359-1001 > + If your life is a hard drive, | 13 Roberts Road > + Christ can be your backup. | Newtown Square, Pennsylvania 19073 -- Bruce Momjian | http://candle.pha.pa.us pgman@candle.pha.pa.us | (610) 359-1001+ If your life is a hard drive, | 13 Roberts Road + Christ can be your backup. | Newtown Square, Pennsylvania19073
Bruce Momjian <pgman@candle.pha.pa.us> writes:
> OK, so what do we do with 7.3.1. Increment major or minor?
Major. I thought you did it already?
regards, tom lane
Tom Lane wrote: > Bruce Momjian <pgman@candle.pha.pa.us> writes: > > OK, so what do we do with 7.3.1. Increment major or minor? > > Major. I thought you did it already? I did only minor, which I knew was safe. Do folks realize this will require recompile of applications by 7.3 users moving to 7.3.1? That seems very drastic, and there have been very few problem reports about the NOTIFY change. -- Bruce Momjian | http://candle.pha.pa.us pgman@candle.pha.pa.us | (610) 359-1001+ If your life is a hard drive, | 13 Roberts Road + Christ can be your backup. | Newtown Square, Pennsylvania19073
Making something binary incompatible IS an API change! In the case in question an externally visible structure definition was changed - clearly a change of API... Bruce Momjian writes:> Tom Lane wrote:> > Bruce Momjian <pgman@candle.pha.pa.us> writes:> > > So if a recompile fixes it,increment minor, else major.> > > > Wrong --- if you need a recompile then it's not binary-compatible, so> > it shouldbe a major version bump.> > But the previous poster said only API changes were reasons to bump the> major, right?
Guys, can I take this chance to summarise the thread and when the major and minor versions should be updated, perhaps could be added to the developers FAQ if everyone is in agreement? Major Version ============= The major version number should be updated whenever the source of the library changes to make it binary incompatible. Such changes include, but limited to: 1. Removing a public function or structure (or typedef, enum, ...) 2. Modifying a public functions arguments. 3. Removing a field from a public structure. 3. Adding a field to a public structure, unless steps have been previously taken to shield users from such a change, for example by such structures only ever being allocated/instantiated by a library function which would give the new field a suitable default value. Adding a new function would NOT force an increase in the major version number. When the major version is increased all applications which link to the library MUST be recompiled - this is not desirable. When the major version is updated the minor version gets reset. Minor Version ============= The minor version number should be updated whenever the functionality of the library has changed, typically and change in source code between releases would mean an increase in the minor version number so long as it does not require a major version increase. Thanks, Lee.
Guys,
Some further comments on bumbing the major version number which aren't
so cut-n-dry...
Lee Kindness writes:> The major version number should be updated whenever the source of the> library changes to make it
binaryincompatible. Such changes include,> but limited to:> > 1. Removing a public function or structure (or typedef,
enum,...)> > 2. Modifying a public functions arguments.> > 3. Removing a field from a public structure.> > 3. Adding a
fieldto a public structure, unless steps have been> previously taken to shield users from such a change, for example
by>such structures only ever being allocated/instantiated by a library> function which would give the new field a
suitabledefault value.
For #2 steps could be taken to maintain binary compatibility across
minor PostgreSQL releases (e.g. the 7.2 series, the 7.3 series, the
7.4/8.0 series). Consider the following function
void print_stuff(int arg1, int arg2){ printf("stuff: %d %d\n", arg1, arg2);}
If we wanted to add a third argument:
void print_stuff(int arg1, int arg2, int arg3){ printf("stuff: %d %d %d\n", arg1, arg2, arg3);}
Then doing it like this:
void print_stuff2(int arg1, int arg2, int arg3){ printf("stuff: %d %d %d\n", arg1, arg2, arg3);}
void print_stuff(int arg1, int arg2){ print_stuff(arg1, arg2, 0);}
would maintain binary compatibility. Obviously this would add a fair
bit of cruft if used extensively, but considering the changes between
minor versions would probably be worthwhile to avoid bumping library
major version. Naturally in the next major version print_stuff() would
assume the functionality and arguments of print_stuff2().
Lee.
On Fri, Dec 13, 2002 at 12:34:58AM -0500, Bruce Momjian wrote: > > I did only minor, which I knew was safe. Do folks realize this will > require recompile of applications by 7.3 users moving to 7.3.1? That > seems very drastic, and there have been very few problem reports about > the NOTIFY change. In my case, I only know it broke some test cases. But still, isn't it better to err on the safe side and at least give the user a clue that the upgrade isn't necessarily supposed to work with his existing code? Jeroen
On Fri, 2002-12-13 at 05:34, Bruce Momjian wrote: > Tom Lane wrote: > > Bruce Momjian <pgman@candle.pha.pa.us> writes: > > > OK, so what do we do with 7.3.1. Increment major or minor? > > > > Major. I thought you did it already? > > I did only minor, which I knew was safe. Do folks realize this will > require recompile of applications by 7.3 users moving to 7.3.1? That > seems very drastic, and there have been very few problem reports about > the NOTIFY change. If the ABI is different, they need to recompile but don't have any indication of it. This is bad. If the major number changes, they can keep the old library around for the benefits of applications that have not yet been recompiled, while newly compiled applications can use the new library So please change it. -- Oliver Elphick Oliver.Elphick@lfix.co.uk Isle of Wight, UK http://www.lfix.co.uk/oliver GPG: 1024D/3E1D0C1C: CA12 09E0 E8D5 8870 5839 932A 614D 4C34 3E1D 0C1C ======================================== "For thou art my hope, O Lord GOD; thou art my trust from my youth." Psalms 71:5
Lee Kindness wrote: > Making something binary incompatible IS an API change! In the case in > question an externally visible structure definition was changed - > clearly a change of API... My point was that I thought it was a source-level API change that required a major bump. I now see it can be a binary change too, so anything that requires a client recompile is a major bump. -- Bruce Momjian | http://candle.pha.pa.us pgman@candle.pha.pa.us | (610) 359-1001+ If your life is a hard drive, | 13 Roberts Road + Christ can be your backup. | Newtown Square, Pennsylvania19073
Oliver Elphick wrote: > On Fri, 2002-12-13 at 05:34, Bruce Momjian wrote: > > Tom Lane wrote: > > > Bruce Momjian <pgman@candle.pha.pa.us> writes: > > > > OK, so what do we do with 7.3.1. Increment major or minor? > > > > > > Major. I thought you did it already? > > > > I did only minor, which I knew was safe. Do folks realize this will > > require recompile of applications by 7.3 users moving to 7.3.1? That > > seems very drastic, and there have been very few problem reports about > > the NOTIFY change. > > If the ABI is different, they need to recompile but don't have any > indication of it. This is bad. > > If the major number changes, they can keep the old library around for > the benefits of applications that have not yet been recompiled, while > newly compiled applications can use the new library > > So please change it. The point is that we are changing it for 7.3.1, so though 7.3 libpq is almost identical to 7.3.1 libpq, we are going to bump the major and force recompile. The binary API change was from 7.2 to 7.3, not 7.3 to 7.3.1. Do people still want a major bump in 7.3.1? Clearly we should have bumped the major in 7.3, but we didn't. -- Bruce Momjian | http://candle.pha.pa.us pgman@candle.pha.pa.us | (610) 359-1001+ If your life is a hard drive, | 13 Roberts Road + Christ can be your backup. | Newtown Square, Pennsylvania19073
Bruce Momjian <pgman@candle.pha.pa.us> writes:
> The point is that we are changing it for 7.3.1, so though 7.3 libpq is
> almost identical to 7.3.1 libpq, we are going to bump the major and
> force recompile. The binary API change was from 7.2 to 7.3, not 7.3 to
> 7.3.1. Do people still want a major bump in 7.3.1?
Yes. We already discussed this: the consensus was that it's better to
inconvenience the early adopters of 7.3 than leave a time bomb sitting
there throughout the 7.3.* cycle.
BTW, if we do make a major bump, that would suggest we ought to get
7.3.1 out as soon as possible, so as to minimize the uptake of 7.3.
I have been thinking that a mid-Dec release of 7.3.1 would be a good
plan anyway, since we already know of several moderately serious bugs
in 7.3.
regards, tom lane
Tom Lane wrote: > Bruce Momjian <pgman@candle.pha.pa.us> writes: > > The point is that we are changing it for 7.3.1, so though 7.3 libpq is > > almost identical to 7.3.1 libpq, we are going to bump the major and > > force recompile. The binary API change was from 7.2 to 7.3, not 7.3 to > > 7.3.1. Do people still want a major bump in 7.3.1? > > Yes. We already discussed this: the consensus was that it's better to > inconvenience the early adopters of 7.3 than leave a time bomb sitting > there throughout the 7.3.* cycle. > > BTW, if we do make a major bump, that would suggest we ought to get > 7.3.1 out as soon as possible, so as to minimize the uptake of 7.3. > I have been thinking that a mid-Dec release of 7.3.1 would be a good > plan anyway, since we already know of several moderately serious bugs > in 7.3. OK, let me see if I understand the ramifications. If you install 7.3.1 _on_top_of 7.3, both major versions will exist, and you your old binaries will continue to work. However, if you delete the old libraries, then install, anything compiled against 7.3 will not work until it is recompiled. Also, any new linking against a 7.3.1 that has both major version numbers will use the newer major? Is that right? (I honestly never understood all this before.) -- Bruce Momjian | http://candle.pha.pa.us pgman@candle.pha.pa.us | (610) 359-1001+ If your life is a hard drive, | 13 Roberts Road + Christ can be your backup. | Newtown Square, Pennsylvania19073
Bruce Momjian writes: > > No, the run-time linker only looks at the major version. > > Then what value is there to incrementing the minor number? For those platforms that have an ldconfig program, the ldconfig will update the symlinks to the shared library based on the minor version number. So if you have installed somewhere libpq.so.2.2 libpq.so.2.3 then ldconfig will create a symlink libpq.so.2 -> libpq.so.2.3 because that is the newest/best version. Note that "libpq.so.2" is the file name that the dynamic loader will actually look for. Other platforms probably have a mechanism that comes out to the same effect. -- Peter Eisentraut peter_e@gmx.net
On Fri, 2002-12-13 at 19:13, Bruce Momjian wrote: > OK, let me see if I understand the ramifications. > > If you install 7.3.1 _on_top_of 7.3, both major versions will exist, and > you your old binaries will continue to work. However, if you delete the > old libraries, then install, anything compiled against 7.3 will not work > until it is recompiled. Yes. You will have libpq.so.3.0 in 7.3.1; and you have libpq.so.2.2 from 7.3 (and also from 7.2.x, though in fact they are different). If you have installed 7.3.1 on top of 7.3, you will have libpq.so.3 (symlinked to libpq.so.3.0) from 7.3.1, and libpq.so.2 (symlinked to libpq.so.2.2) from an earlier release. > > Also, any new linking against a 7.3.1 that has both major version > numbers will use the newer major? Is that right? 7.3.1 will only have the new major version number; the old one will have come from 7.3 or earlier. The library chosen by the linker is the one linked to libpq.so. -- Oliver Elphick <olly@lfix.co.uk> LFIX Limited
On Fri, Dec 13, 2002 at 09:06:47PM +0000, Oliver Elphick wrote: > > Yes. You will have libpq.so.3.0 in 7.3.1; and you have libpq.so.2.2 > from 7.3 (and also from 7.2.x, though in fact they are different). If > you have installed 7.3.1 on top of 7.3, you will have libpq.so.3 > (symlinked to libpq.so.3.0) from 7.3.1, and libpq.so.2 (symlinked to > libpq.so.2.2) from an earlier release. Doesn't that mean that a user upgrading from 7.3 to 7.3.1 will have two libraries, libpq.so.2.2 and libpq.so.3, that both adhere to the 7.3 ABI? Perhaps 7.3.1 could include a true, 7.2-style libpq.so.2.2 to overwrite any 7.3-style version that the original 7.3 may have installed under that name? Jeroen
Jeroen T. Vermeulen wrote: > On Fri, Dec 13, 2002 at 09:06:47PM +0000, Oliver Elphick wrote: > > > > Yes. You will have libpq.so.3.0 in 7.3.1; and you have libpq.so.2.2 > > from 7.3 (and also from 7.2.x, though in fact they are different). If > > you have installed 7.3.1 on top of 7.3, you will have libpq.so.3 > > (symlinked to libpq.so.3.0) from 7.3.1, and libpq.so.2 (symlinked to > > libpq.so.2.2) from an earlier release. > > Doesn't that mean that a user upgrading from 7.3 to 7.3.1 will have two > libraries, libpq.so.2.2 and libpq.so.3, that both adhere to the 7.3 ABI? > > Perhaps 7.3.1 could include a true, 7.2-style libpq.so.2.2 to overwrite > any 7.3-style version that the original 7.3 may have installed under that > name? That's an interesting idea, but then 7.3 binaries would link to libpq.so.2.2, which is bad. -- Bruce Momjian | http://candle.pha.pa.us pgman@candle.pha.pa.us | (610) 359-1001+ If your life is a hard drive, | 13 Roberts Road + Christ can be your backup. | Newtown Square, Pennsylvania19073
Bruce Momjian <pgman@candle.pha.pa.us> writes:
> Jeroen T. Vermeulen wrote:
>> Perhaps 7.3.1 could include a true, 7.2-style libpq.so.2.2 to overwrite
>> any 7.3-style version that the original 7.3 may have installed under that
>> name?
> That's an interesting idea, but then 7.3 binaries would link to
> libpq.so.2.2, which is bad.
There are a number of problems with that, but the biggie is that the old
binary API is inherently dependent on NAMEDATALEN. We can *not* ship a
library that is both 100% backwards compatible and 100% compatible to
a standard-issue 7.3 server.
regards, tom lane
Bruce Momjian wrote: > Tom Lane wrote: > > Bruce Momjian <pgman@candle.pha.pa.us> writes: > > > OK, so what do we do with 7.3.1. Increment major or minor? > > > > Major. I thought you did it already? > > I did only minor, which I knew was safe. Do folks realize this will > require recompile of applications by 7.3 users moving to 7.3.1? That > seems very drastic, and there have been very few problem reports about > the NOTIFY change. Keep in mind that people who are running applications compiled against the older (7.2) library have the option of keeping the older library around. They can recompile their applications to link against the newer library at their leisure. Someone who has recompiled their applications against the 7.3 libraries is already safe -- they can install 7.3.1 and keep the old 7.3 libraries around at the same time if they don't want to recompile their applications again. They just have to be careful to not use any precompiled applications that were linked against the 7.2 series. The people who are running 7.2 have the option of keeping their 7.2 libraries around while upgrading to 7.3.1. Any applications that are compiled against the 7.2 libraries will still work. The only people who are in trouble are the people who upgraded from 7.2 to 7.3 but did not recompile some of their applications. They have three options: install 7.3.1 and recompile their applications, install 7.3.1 and reinstall the 7.2 shared libraries, or recompile their applications against 7.3 (and then upgrade to 7.3.1 at their leisure). Obviously the last option is the worst of the lot: if they're going to recompile their applications, they may as well do so against the newer (7.3.1) libraries with a higher major number so there is no confusion about which libraries are really compatible with which. -- Kevin Brown kevin@sysexperts.com
OK, I have updated the libpq major number in 7.3.X, and updated major and minor in HEAD. Do I need to increment the other interfaces that _use_ libpq, like ecpg? I think so. --------------------------------------------------------------------------- Oliver Elphick wrote: > On Fri, 2002-12-13 at 19:13, Bruce Momjian wrote: > > OK, let me see if I understand the ramifications. > > > > If you install 7.3.1 _on_top_of 7.3, both major versions will exist, and > > you your old binaries will continue to work. However, if you delete the > > old libraries, then install, anything compiled against 7.3 will not work > > until it is recompiled. > > Yes. You will have libpq.so.3.0 in 7.3.1; and you have libpq.so.2.2 > from 7.3 (and also from 7.2.x, though in fact they are different). If > you have installed 7.3.1 on top of 7.3, you will have libpq.so.3 > (symlinked to libpq.so.3.0) from 7.3.1, and libpq.so.2 (symlinked to > libpq.so.2.2) from an earlier release. > > > > > Also, any new linking against a 7.3.1 that has both major version > > numbers will use the newer major? Is that right? > > 7.3.1 will only have the new major version number; the old one will have > come from 7.3 or earlier. The library chosen by the linker is the one > linked to libpq.so. > > > -- > Oliver Elphick <olly@lfix.co.uk> > LFIX Limited > > -- Bruce Momjian | http://candle.pha.pa.us pgman@candle.pha.pa.us | (610) 359-1001+ If your life is a hard drive, | 13 Roberts Road + Christ can be your backup. | Newtown Square, Pennsylvania19073
OK, I have added this to tools/RELEASE_CHANGES. New file attached. --------------------------------------------------------------------------- Lee Kindness wrote: > Guys, can I take this chance to summarise the thread and when the > major and minor versions should be updated, perhaps could be added to > the developers FAQ if everyone is in agreement? > > Major Version > ============= > > The major version number should be updated whenever the source of the > library changes to make it binary incompatible. Such changes include, > but limited to: > > 1. Removing a public function or structure (or typedef, enum, ...) > > 2. Modifying a public functions arguments. > > 3. Removing a field from a public structure. > > 3. Adding a field to a public structure, unless steps have been > previously taken to shield users from such a change, for example by > such structures only ever being allocated/instantiated by a library > function which would give the new field a suitable default value. > > Adding a new function would NOT force an increase in the major version > number. When the major version is increased all applications which > link to the library MUST be recompiled - this is not desirable. When > the major version is updated the minor version gets reset. > > Minor Version > ============= > > The minor version number should be updated whenever the functionality > of the library has changed, typically and change in source code > between releases would mean an increase in the minor version number so > long as it does not require a major version increase. > > Thanks, Lee. > > ---------------------------(end of broadcast)--------------------------- > TIP 5: Have you checked our extensive FAQ? > > http://www.postgresql.org/users-lounge/docs/faq.html > -- Bruce Momjian | http://candle.pha.pa.us pgman@candle.pha.pa.us | (610) 359-1001 + If your life is a hard drive, | 13 Roberts Road + Christ can be your backup. | Newtown Square, Pennsylvania 19073 * Version numbers configure.in and configure bump interface version numbers o src/interfaces/*/Makefile o src/interfaces/libpq/libpq.rc o src/include/pg_config.h.win32 * Release notes update HISTORY and later doc/src/sgml/release.sgml * Documentation document all new features update help output from inside the programs doc/src/sgml/ref manual pages * Ports update ports list in doc/src/sgml/installation.sgml platform-specific FAQ's, if needed * Miscellaneous files doc/bug.template * Update pg_upgrade to handle new version, or disable * Update copyright year? --------------------------------------------------------------------------- Major Version ============= The major version number should be updated whenever the source of the library changes to make it binary incompatible. Such changes include, but are not limited to: 1. Removing a public function or structure (or typedef, enum, ...) 2. Modifying a public functions arguments. 3. Removing a field from a public structure. 3. Adding a field to a public structure, unless steps have been previously taken to shield users from such a change, for example by such structures only ever being allocated/instantiated by a library function which would give the new field a suitable default value. Adding a new function would NOT force an increase in the major version number. When the major version is increased all applications which link to the library MUST be recompiled - this is not desirable. When the major version is updated the minor version gets reset. Minor Version ============= The minor version number should be updated whenever the functionality of the library has changed, typically and change in source code between releases would mean an increase in the minor version number so long as it does not require a major version increase. Minimizing Changes ================== When modifying public functions arguments, steps should be taken to maintain binary compatibility across minor PostgreSQL releases (e.g. the 7.2 series, the 7.3 series, the 7.4/8.0 series). Consider the following function: void print_stuff(int arg1, int arg2) { printf("stuff: %d %d\n", arg1, arg2); } If we wanted to add a third argument: void print_stuff(int arg1, int arg2, int arg3) { printf("stuff: %d %d %d\n", arg1, arg2, arg3); } Then doing it like this: void print_stuff2(int arg1, int arg2, int arg3) { printf("stuff: %d %d %d\n", arg1, arg2, arg3); } void print_stuff(int arg1, int arg2) { print_stuff(arg1, arg2, 0); } would maintain binary compatibility. Obviously this would add a fair bit of cruft if used extensively, but considering the changes between minor versions would probably be worthwhile to avoid bumping library major version. Naturally in the next major version print_stuff() would assume the functionality and arguments of print_stuff2(). Lee Kindness
I have added this info too.
---------------------------------------------------------------------------
Lee Kindness wrote:
> Guys,
>
> Some further comments on bumbing the major version number which aren't
> so cut-n-dry...
>
> Lee Kindness writes:
> > The major version number should be updated whenever the source of the
> > library changes to make it binary incompatible. Such changes include,
> > but limited to:
> >
> > 1. Removing a public function or structure (or typedef, enum, ...)
> >
> > 2. Modifying a public functions arguments.
> >
> > 3. Removing a field from a public structure.
> >
> > 3. Adding a field to a public structure, unless steps have been
> > previously taken to shield users from such a change, for example by
> > such structures only ever being allocated/instantiated by a library
> > function which would give the new field a suitable default value.
>
> For #2 steps could be taken to maintain binary compatibility across
> minor PostgreSQL releases (e.g. the 7.2 series, the 7.3 series, the
> 7.4/8.0 series). Consider the following function
>
> void print_stuff(int arg1, int arg2)
> {
> printf("stuff: %d %d\n", arg1, arg2);
> }
>
> If we wanted to add a third argument:
>
> void print_stuff(int arg1, int arg2, int arg3)
> {
> printf("stuff: %d %d %d\n", arg1, arg2, arg3);
> }
>
> Then doing it like this:
>
> void print_stuff2(int arg1, int arg2, int arg3)
> {
> printf("stuff: %d %d %d\n", arg1, arg2, arg3);
> }
>
> void print_stuff(int arg1, int arg2)
> {
> print_stuff(arg1, arg2, 0);
> }
>
> would maintain binary compatibility. Obviously this would add a fair
> bit of cruft if used extensively, but considering the changes between
> minor versions would probably be worthwhile to avoid bumping library
> major version. Naturally in the next major version print_stuff() would
> assume the functionality and arguments of print_stuff2().
>
> Lee.
>
> ---------------------------(end of broadcast)---------------------------
> TIP 4: Don't 'kill -9' the postmaster
>
-- Bruce Momjian | http://candle.pha.pa.us pgman@candle.pha.pa.us | (610)
359-1001+ If your life is a hard drive, | 13 Roberts Road + Christ can be your backup. | Newtown Square,
Pennsylvania19073
I figured out why I forgot to update the minor number for 7.3. The old RELEASE_CHANGES file had: bump interface version numbers o src/interfaces/libpq/libpq.rc o src/include/pg_config.h.win32 I had forgotten to explicitly list the Makefile changes. The new list is: bump interface version numbers o src/interfaces/*/Makefile o src/interfaces/libpq/libpq.rc o src/include/pg_config.h.win32 Of course, incrementing the minor number may not have even helped us because we needed a major increase, which I didn't understand at the time. --------------------------------------------------------------------------- Oliver Elphick wrote: > On Fri, 2002-12-13 at 19:13, Bruce Momjian wrote: > > OK, let me see if I understand the ramifications. > > > > If you install 7.3.1 _on_top_of 7.3, both major versions will exist, and > > you your old binaries will continue to work. However, if you delete the > > old libraries, then install, anything compiled against 7.3 will not work > > until it is recompiled. > > Yes. You will have libpq.so.3.0 in 7.3.1; and you have libpq.so.2.2 > from 7.3 (and also from 7.2.x, though in fact they are different). If > you have installed 7.3.1 on top of 7.3, you will have libpq.so.3 > (symlinked to libpq.so.3.0) from 7.3.1, and libpq.so.2 (symlinked to > libpq.so.2.2) from an earlier release. > > > > > Also, any new linking against a 7.3.1 that has both major version > > numbers will use the newer major? Is that right? > > 7.3.1 will only have the new major version number; the old one will have > come from 7.3 or earlier. The library chosen by the linker is the one > linked to libpq.so. > > > -- > Oliver Elphick <olly@lfix.co.uk> > LFIX Limited > > -- Bruce Momjian | http://candle.pha.pa.us pgman@candle.pha.pa.us | (610) 359-1001+ If your life is a hard drive, | 13 Roberts Road + Christ can be your backup. | Newtown Square, Pennsylvania19073
On Sat, 2002-12-14 at 18:59, Bruce Momjian wrote: > OK, I have updated the libpq major number in 7.3.X, and updated major > and minor in HEAD. Do I need to increment the other interfaces that > _use_ libpq, like ecpg? I think so. I don't think so. $ ldd /usr/lib/postgresql/lib/libecpg.solibpq.so.2 => /usr/lib/libpq.so.2 (0x40019000)libc.so.6 => /lib/libc.so.6 (0x4002e000)libssl.so.0.9.6=> /usr/lib/i686/libssl.so.0.9.6 (0x40141000)libcrypto.so.0.9.6 => /usr/lib/i686/libcrypto.so.0.9.6(0x4016e000)libkrb5.so.17 => /usr/lib/libkrb5.so.17 (0x40226000)libcrypt.so.1 => /lib/libcrypt.so.1(0x4025c000)libresolv.so.2 => /lib/libresolv.so.2 (0x40289000)libnsl.so.1 => /lib/libnsl.so.1 (0x4029a000)/lib/ld-linux.so.2=> /lib/ld-linux.so.2 (0x80000000)libdl.so.2 => /lib/libdl.so.2 (0x402ad000)libcom_err.so.1=> /usr/lib/libcom_err.so.1 (0x402b0000)libasn1.so.5 => /usr/lib/libasn1.so.5 (0x402b2000)libroken.so.9=> /usr/lib/libroken.so.9 (0x402d2000)libdb3.so.3 => /usr/lib/libdb3.so.3 (0x402e3000) Here libecpg will look for libpq.so.2. When 7.3.1 is released, this libecpg will be replaced by one that looks for libpq.so.3. But I think that, unless the API of libecpg changes, its version should stay the same. If you change it with libpq, you must also change it with all the other libraries it links in, like libkrb5 and libdb3. That is clearly impracticable. -- Oliver Elphick Oliver.Elphick@lfix.co.uk Isle of Wight, UK http://www.lfix.co.uk/oliver GPG: 1024D/3E1D0C1C: CA12 09E0 E8D5 8870 5839 932A 614D 4C34 3E1D 0C1C ======================================== "But I will hope continually, and will yet praise thee more and more." Psalms 71:14
Bruce Momjian wrote: > > OK, I have updated the libpq major number in 7.3.X, and updated major > and minor in HEAD. Do I need to increment the other interfaces that > _use_ libpq, like ecpg? I think so. You'll only need to increment the major number of those other interfaces that are no longer binary-compatible with their immediate predecessors. That is, if the version of libecpg that ships with 7.3.1 is incompatible with the version of libecpg that ships with 7.3, then you should bump its major number (the one that shipped with 7.3 should have had its major number bumped if it was incompatible with the one that shipped with 7.2.3). But its binary interface should be independent of the binary interface of libpg. When you build a shared library, you link it against any shared libraries it depends on. The resulting dependency list is contained within the shared library the same way it's contained in an application. You can run ldd on shared libraries just as you can on applications. It might be helpful to think of the major number as being the same as a protocol description number. You change the protocol description number when you make changes to the protocol that would make a server using the new version of the protocol incompatible with a client using the old version of the protocol. In fact, there's really very little conceptual difference between a protocol and an API: both are a means for two entities to communicate with one another. Change the API and you have to do something to make it clear that the API has changed. Same deal with a protocol. I don't know if what I'm saying here makes much sense to you, but I hope it helps... -- Kevin Brown kevin@sysexperts.com
Bruce Momjian writes: > Do I need to increment the other interfaces that > _use_ libpq, like ecpg? If and only if the libpq API is part of their documented API. For ecpg I think this is not the case, but for libpq++ it would seem to be the case. -- Peter Eisentraut peter_e@gmx.net
Peter Eisentraut <peter_e@gmx.net> writes:
> Bruce Momjian writes:
>> Do I need to increment the other interfaces that
>> _use_ libpq, like ecpg?
> If and only if the libpq API is part of their documented API. For ecpg I
> think this is not the case, but for libpq++ it would seem to be the case.
However, an app linked against libpq++ would also be linked against
libpq, and so the incompatibility will be flagged by the linker anyway.
I can see no need to bump libpq++'s own number.
regards, tom lane
On Sun, Dec 15, 2002 at 11:21:07AM -0500, Tom Lane wrote: > > However, an app linked against libpq++ would also be linked against > libpq, and so the incompatibility will be flagged by the linker anyway. > I can see no need to bump libpq++'s own number. Plus, of course, libpq++ being a C++ library will break compatibility at some compiler upgrades--which isn't even necessarily visible to anyone compiling a postgres release. Jeroen
But it's something they should of already had to do. We're just paying late for old sins. ;) Greg On Thu, 2002-12-12 at 23:34, Bruce Momjian wrote: > Tom Lane wrote: > > Bruce Momjian <pgman@candle.pha.pa.us> writes: > > > OK, so what do we do with 7.3.1. Increment major or minor? > > > > Major. I thought you did it already? > > I did only minor, which I knew was safe. Do folks realize this will > require recompile of applications by 7.3 users moving to 7.3.1? That > seems very drastic, and there have been very few problem reports about > the NOTIFY change. -- Greg Copeland <greg@copelandconsulting.net> Copeland Computer Consulting
Tom Lane wrote: > Peter Eisentraut <peter_e@gmx.net> writes: > > Bruce Momjian writes: > >> Do I need to increment the other interfaces that > >> _use_ libpq, like ecpg? > > > If and only if the libpq API is part of their documented API. For ecpg I > > think this is not the case, but for libpq++ it would seem to be the case. > > However, an app linked against libpq++ would also be linked against > libpq, and so the incompatibility will be flagged by the linker anyway. > I can see no need to bump libpq++'s own number. New question --- didn't we change the externally visible PGNotify structure in libpq-fe.h in 7.3, and as returned by PQnotifies: PGnotify *PQnotifies(PGconn *conn) meaning if ecpg references PGnotify, should it have a new major number too, so actually, we did change the API in 7.3 and not just the binary compatibility. -- Bruce Momjian | http://candle.pha.pa.us pgman@candle.pha.pa.us | (610) 359-1001+ If your life is a hard drive, | 13 Roberts Road + Christ can be your backup. | Newtown Square, Pennsylvania19073
Bruce Momjian <pgman@candle.pha.pa.us> writes:
> meaning if ecpg references PGnotify, should it have a new major number
> too,
No, because PGnotify is *not part of ecpg's API*.
The ecpg library, when compiled, will show a dependency on the new major
number for libpq. That does not mean that applications linked to ecpg
need to be recompiled. They don't (unless they depend directly on libpq
too).
regards, tom lane
Tom Lane wrote: > Bruce Momjian <pgman@candle.pha.pa.us> writes: > > meaning if ecpg references PGnotify, should it have a new major number > > too, > > No, because PGnotify is *not part of ecpg's API*. > > The ecpg library, when compiled, will show a dependency on the new major > number for libpq. That does not mean that applications linked to ecpg > need to be recompiled. They don't (unless they depend directly on libpq > too). OK, got it. That's the think I needed to understand. -- Bruce Momjian | http://candle.pha.pa.us pgman@candle.pha.pa.us | (610) 359-1001+ If your life is a hard drive, | 13 Roberts Road + Christ can be your backup. | Newtown Square, Pennsylvania19073
On Mon, Dec 16, 2002 at 11:01:00AM -0500, Bruce Momjian wrote: > > New question --- didn't we change the externally visible PGNotify > structure in libpq-fe.h in 7.3, and as returned by PQnotifies: Speaking of which, what if user relies on sizeof(PGnotify::relname)? That code will recompile without any problems, but it won't actually work as expected. So in a way, the change may require more than a simple recompile. Jeroen
On Mon, Dec 16, 2002 at 05:41:06PM +0100, Jeroen T. Vermeulen wrote:
>
> Speaking of which, what if user relies on sizeof(PGnotify::relname)? ^
code
Jeroen
Jeroen T. Vermeulen writes:> On Mon, Dec 16, 2002 at 05:41:06PM +0100, Jeroen T. Vermeulen wrote:> > Speaking of which, whatif user relies on sizeof(PGnotify::relname)?> ^> code Yes, a change in the size of relname makes this binary incompatible and the user code changes may not be just a simple recompile - It all depends on what it being used for! Lee.