Обсуждение: Shared library conflicts

There was a discussion some time back concerning the linking of the 
postgres backend. Some libraries where linked although they where not 
needed, mainly because it was convenient. I had a problem with PL/Java 
since a Sun JVM ships with their own version of libz.so (they call it 
libzip.so). Sun fixed the problem, simply by adding a namespace to all 
functions in their own library so I didn't stress the issue any further. 
Now this bites me again. Sun forgot to remove the old functions in their 
libzip.so on the amd64 platform.

I have of course reported this to Sun and I expect it to be fixed in 
future releases of Java but shouldn't this be fixed for PostgreSQL too? 
Perhaps we should consider this a more generic problem. The more 
libraries that are linked with the backend, the greater the risk that 
add-on modules will run into conflicts. What effort would be involved to 
fix this once and for all?

Another related question. What happens when I use --without-zlib? Does 
it have any effect on besides disabling compression for the dump/restore 
utilities? Is there anyway to make it affect the backend only?

Kind Regards,
Thomas Hallgren

"Thomas Hallgren" <thomas@tada.se>
>
> Another related question. What happens when I use --without-zlib? Does it 
> have any effect on besides disabling compression for the dump/restore 
> utilities? Is there anyway to make it affect the backend only?

--without-zlib will affected LIBS and HAVE_LIBZ defined in configure.
I searched HAVE_LIBZ in the source code, and find only pg_dump use it.
I think we can change LIBS to not include "-lz" in configure, and add "-lz"
for pg_dump in its Makefile.

With regards,
William ZHANG

>
> Kind Regards,
> Thomas Hallgren
>
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On Fri, Jun 23, 2006 at 10:45:29AM +0200, Thomas Hallgren wrote:
> There was a discussion some time back concerning the linking of the
> postgres backend. Some libraries where linked although they where not
> needed, mainly because it was convenient.

AIUI, this was fixed in -HEAD. In the Makefile there's a filter command
to strip libraries not needed. One of them is libz.

From src/backend/Makefile:
# The backend doesn't need everything that's in LIBS, however
LIBS := $(filter-out -lz -lreadline -ledit -ltermcap -lncurses -lcurses, $(LIBS))

Have a nice day,
--
Martijn van Oosterhout   <kleptog@svana.org>   http://svana.org/kleptog/
> From each according to his ability. To each according to his ability to litigate.

That's good news. Any chance of getting this fix backported to 8.1? Or 
at least, the libz part of it?

Regards,
Thomas Hallgren


Martijn van Oosterhout wrote:
> On Fri, Jun 23, 2006 at 10:45:29AM +0200, Thomas Hallgren wrote:
>   
>> There was a discussion some time back concerning the linking of the 
>> postgres backend. Some libraries where linked although they where not 
>> needed, mainly because it was convenient.
>>     
>
> AIUI, this was fixed in -HEAD. In the Makefile there's a filter command
> to strip libraries not needed. One of them is libz.
>
> From src/backend/Makefile:
> # The backend doesn't need everything that's in LIBS, however
> LIBS := $(filter-out -lz -lreadline -ledit -ltermcap -lncurses -lcurses, $(LIBS))
>
> Have a nice day,
>