Re: [HACKERS] AIX shared libraries
Tom Lane wrote: Ugh. So given that linker behavior, it's basically impossible to support multiple libpq versions in the same directory anyway on AIX. It is possible, if you have both versions of the shared object in the same library. Essentially what I proposed for 3b). It is the way IBM does it with their system libraries. I set up a sample with libpq version 4 and version 5 in libpq.a: $ dump -ov /postgres/8.2/lib/libpq.a /postgres/8.2/lib/libpq.a[libpq.so.4]: ***Object Module Header*** [...] Flags=( EXEC DYNLOAD SHROBJ LOADONLY DEP_SYSTEM ) [...] /postgres/8.2/lib/libpq.a[libpq.so.5]: ***Object Module Header*** [...] Flags=( EXEC DYNLOAD SHROBJ DEP_SYSTEM ) [...] The linker will only link against the shared object that does not have the LOADONLY flag set, but stuff linked against libpq.a(libpq.so.4) will continue to work. I concur with your 3a) then. Do you have time to do that now? I'll start right away. Yours, Laurenz Albe ---(end of broadcast)--- TIP 3: Have you checked our extensive FAQ? http://www.postgresql.org/docs/faq
Re: [HACKERS] AIX shared libraries
Tom Lane wrote: I think there's a reasonable argument that by installing a .a file that isn't a shared library, we are violating the platform's conventions. Hm. This seems possible with some moderate hacking on Makefile.shlib (certainly it'd be no more invasive than the existing Windows-specific platform variants). [...] Another issue with installing only .a is that there's no provision for versioning in .a library names ... what happens to someone who needs two generations of libpq on his machine? Ok, I have spent some time researching and thinking, and I have three proposals how to deal with linking on AIX. 1) Leave everything as it is and add the LDAP libraries to the AIX hack in Makefile.shlib. Pros: - Little work. Cons: - PostgreSQL will continue to be statically linked on AIX (unless somebody feeds configure the right LDFLAGS). 2) Remove the AIX hack from Makefile.shlib, add -brtl and -blibpath:$(rpathdir):*-L directories in LDPATH*:/usr/lib:/lib (this sets the AIX equivalent for RPATH) to LDFLAGS for AIX. Pros: - Dynamic linking on AIX. - The organization of the libraries (libpq.a static, libpq.so dynamic) is similar to other operating systems. Cons: - The library organization is counter-intuitive to AIX people, and most people will inadvertedly link statically when linking against libpq. - According to Rocco Altier it will not work on historic versions of AIX (no -brtl flag). 3) Major hacking in Makefile.shlib to achieve the following: - libXX.so.n is built from libXX.a in the traditional way. Then libXX.a is deleted, and recreated as archive containing libXX.so.n. - Linking takes place withOUT -brtl, but with -blibpath:... as in 2). - When the shared libs are installed, I see two options: a) copy (and overwrite) libXX.a to libdir, do not install libXX.so.n b) Look for existing libXX.a in libdir, extract all libXX.so.k from it, mark them LOADONLY with 'strip -e libXX.so.k', create a new libXX.a with these objects and the new libXX.so.n Pros: - Dynamic linking on AIX. - AIX-conforming organization of libraries. - In the case of 3)b), multiple versions of the library can be retained in the same archive. Linking is only possible with the latest versions, but old programs continue to work. - 3)a) will probably work on older versions of AIX (I hope there's a -blibpath flag). Cons: - Much work, particularly with 3)b). - Library organization on AIX will be different from other platforms. - 3)b) will probably not work on old versions of AIX (I read a posting that makes me believe that 'strip -e' was not around before 4.3.3. I am willing to implement whatever solution we decide upon. I personally would prefer 3)a), but am happy with anything except 1). Yours, Laurenz Albe I personally would prefer 3)a) ---(end of broadcast)--- TIP 3: Have you checked our extensive FAQ? http://www.postgresql.org/docs/faq
Re: [HACKERS] AIX shared libraries
Albe Laurenz [EMAIL PROTECTED] writes: I personally would prefer 3)a) 3) Major hacking in Makefile.shlib to achieve the following: - libXX.so.n is built from libXX.a in the traditional way. Then libXX.a is deleted, and recreated as archive containing libXX.so.n. - Linking takes place withOUT -brtl, but with -blibpath:... as in 2). - When the shared libs are installed, I see two options: a) copy (and overwrite) libXX.a to libdir, do not install libXX.so.n Hm. The objection I see to this is that it will not support concurrent installation of multiple libpq versions. What about 4) Build and install only libXX.so.n, don't install libXX.a at all 5) As 4), plus actively remove any libXX.a seen in the install directory regards, tom lane ---(end of broadcast)--- TIP 9: In versions below 8.0, the planner will ignore your desire to choose an index scan if your joining column's datatypes do not match
Re: [HACKERS] AIX shared libraries
Tom Lane wrote: 3) Major hacking in Makefile.shlib to achieve the following: - libXX.so.n is built from libXX.a in the traditional way. Then libXX.a is deleted, and recreated as archive containing libXX.so.n. - Linking takes place withOUT -brtl, but with -blibpath:... as in 2). - When the shared libs are installed, I see two options: a) copy (and overwrite) libXX.a to libdir, do not install libXX.so.n Hm. The objection I see to this is that it will not support concurrent installation of multiple libpq versions. What about 4) Build and install only libXX.so.n, don't install libXX.a at all Won't work - the linker looks for libXX.so and won't find libXX.so.n. If you create a symbolic link libXX.so -- libXX.so.n, you can link, but the executable will depend on libXX.so and not on libXX.so.n. Moreover, you cannot link statically any more because in a static link only libXX.a files will be searched... 5) As 4), plus actively remove any libXX.a seen in the install directory Same problem. Yours, Laurenz Albe ---(end of broadcast)--- TIP 1: if posting/reading through Usenet, please send an appropriate subscribe-nomail command to [EMAIL PROTECTED] so that your message can get through to the mailing list cleanly
Re: [HACKERS] AIX shared libraries
Albe Laurenz [EMAIL PROTECTED] writes: Tom Lane wrote: Hm. The objection I see to this is that it will not support concurrent installation of multiple libpq versions. What about 4) Build and install only libXX.so.n, don't install libXX.a at all Won't work - the linker looks for libXX.so and won't find libXX.so.n. If you create a symbolic link libXX.so -- libXX.so.n, you can link, but the executable will depend on libXX.so and not on libXX.so.n. Ugh. So given that linker behavior, it's basically impossible to support multiple libpq versions in the same directory anyway on AIX. I concur with your 3a) then. Do you have time to do that now? regards, tom lane ---(end of broadcast)--- TIP 4: Have you searched our list archives? http://archives.postgresql.org
Re: [HACKERS] AIX shared libraries
[EMAIL PROTECTED] (Rocco Altier) writes: Tom Lane wrote: Is it possible that the rules have changed across AIX versions, and that the code in there now is needful for older versions? I don't think that this behaviour has changed. I remember it from AIX 4.3.2. AIX 4.3 is the first version to support the -brtl. The current code is in place to mimic the behaviour of dlopen, etc, on the older platforms. I think we are at a point that we can stop maintaining AIX older than 4.3 if we want. Version 5.1 is no longer being maintained by IBM; we were some displeased when we heard when support offerings were expiring :-(. Fortunately, we already had plans in place for a migration to 5.3. I have to agree that even 4.3 is really rather old now. Looking at IBM's support lifecycle list... http://www-306.ibm.com/software/info/supportlifecycle/list/a.html AIX version AvailableSupport Withdrawn - 5.1 May 2001 April 2006 5.2 Oct 2002 Sept 2008 5.3 Aug 2004 unannounced, presumably late 2010... I'd guess that 4.3 fell out of support in late 2004. -- let name=cbbrowne and tld=linuxdatabases.info in String.concat @ [name;tld];; http://linuxfinances.info/info/ Of course 5 years from now that will be different, but 5 years from now everyone will be running free GNU on their 200 MIPS, 64M SPARCstation-5. -- Andrew Tanenbaum, 1992. ---(end of broadcast)--- TIP 9: In versions below 8.0, the planner will ignore your desire to choose an index scan if your joining column's datatypes do not match
