Re: [GENERAL] 9.4 -> 9.5 upgrade problem when both python2 and python3 present

[Paul Jones]

On Mon, Jan 11, 2016 at 06:23:06PM -0500, Tom Lane wrote:
> Date: Mon, 11 Jan 2016 18:23:06 -0500
> From: Tom Lane <t...@sss.pgh.pa.us>
> To: Paul Jones <p...@cmicdo.com>
> cc: pgsql-general@postgresql.org
> Subject: Re: [GENERAL] 9.4 -> 9.5 upgrade problem when both python2 and
>  python3 present
> 
> 
> > I guess the thing to do is to manually pg_dump the databases that have
> > python, drop them, upgrade, and then manually restore.
> 
> If you'd rather build a patched version of PG, I have posted a
> work-in-progress patch to address this issue:
> http://www.postgresql.org/message-id/31659.1452538...@sss.pgh.pa.us

It worked most excellently, thank you.

> 
>   regards, tom lane


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Re: [GENERAL] 9.4 -> 9.5 upgrade problem when both python2 and python3 present

[Paul Jones]

On Mon, Jan 11, 2016 at 10:04:16AM -0500, Tom Lane wrote:

/tmp/mutt-mayon-1000-19386-284b6a00794950f414
> Paul Jones  writes:
> > pg_upgrade complains about not being able to find $libdir/plpython3
> > when upgrading a 9.4 cluster that has both python2 and python3 used.
> 
> No, that's not what the error message says:
> 
> > Could not load library "$libdir/plpython3"
> > FATAL:  Python major version mismatch in session
> > DETAIL:  This session has previously used Python major version 2, and it is 
> > now attempting to use Python major version 3.
> > HINT:  Start a new session to use a different Python major version.
> 
> This is a restriction we put in place because libpython2 and libpython3
> don't coexist nicely in the same address space.  Unfortunately, it makes
> it problematic to restore a dump that contains references to both python2
> and python3 functions.
> 
> It looks like pg_upgrade tries to load all libraries from functions in
> any database in the old cluster into a single session in the new cluster,
> which will fail in a scenario like this even if you keep python2 and
> python3 functions rigorously separated into distinct databases.  I'm
> not sure if we could weaken that test enough to work.

I guess the thing to do is to manually pg_dump the databases that have
python, drop them, upgrade, and then manually restore.

> 
> > I dropped the python2 database but still got the problem.
> 
> You must still have at least one database that contains references
> to python2 (check pg_language to be sure).

I thought of that after I pulled the trigger on the mail...

Thanks for the information...

> 
>   regards, tom lane
> 
> 
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Re: [GENERAL] 9.4 -> 9.5 upgrade problem when both python2 and python3 present

[Tom Lane]

Paul Jones  writes:
> On Mon, Jan 11, 2016 at 10:04:16AM -0500, Tom Lane wrote:
>> It looks like pg_upgrade tries to load all libraries from functions in
>> any database in the old cluster into a single session in the new cluster,
>> which will fail in a scenario like this even if you keep python2 and
>> python3 functions rigorously separated into distinct databases.  I'm
>> not sure if we could weaken that test enough to work.

> I guess the thing to do is to manually pg_dump the databases that have
> python, drop them, upgrade, and then manually restore.

If you'd rather build a patched version of PG, I have posted a
work-in-progress patch to address this issue:
http://www.postgresql.org/message-id/31659.1452538...@sss.pgh.pa.us

regards, tom lane


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[GENERAL] 9.4 -> 9.5 upgrade problem when both python2 and python3 present

[Paul Jones]

pg_upgrade complains about not being able to find $libdir/plpython3
when upgrading a 9.4 cluster that has both python2 and python3 used.
Both the 9.4 and 9.5 PGs have been built from source with python2/3 in
the recommended way and the plpython3.so is present in /usr/local/pgsql/lib.

I dropped the python2 database but still got the problem.

The session:


postgres@mayon:~$ pg_upgrade -b /usr/local/pgsql9.4/bin -B /usr/local/pgsql/bin 
-d /mnt/pgdata9.4 -D /mnt/pgdata 
Performing Consistency Checks
-
Checking cluster versions   ok
Checking database user is the install user  ok
Checking database connection settings   ok
Checking for prepared transactions  ok
Checking for reg* system OID user data typesok
Checking for contrib/isn with bigint-passing mismatch   ok
Creating dump of global objects ok
Creating dump of database schemas
ok
Checking for presence of required libraries fatal

Your installation references loadable libraries that are missing from the
new installation.  You can add these libraries to the new installation,
or remove the functions using them from the old installation.  A list of
problem libraries is in the file:
loadable_libraries.txt

Failure, exiting
postgres@mayon:~$ cat *.txt
Could not load library "$libdir/plpython3"
FATAL:  Python major version mismatch in session
DETAIL:  This session has previously used Python major version 2, and it is now 
attempting to use Python major version 3.
HINT:  Start a new session to use a different Python major version.
server closed the connection unexpectedly
This probably means the server terminated abnormally
before or while processing the request.



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Re: [GENERAL] 9.4 -> 9.5 upgrade problem when both python2 and python3 present

[Tom Lane]

Paul Jones  writes:
> pg_upgrade complains about not being able to find $libdir/plpython3
> when upgrading a 9.4 cluster that has both python2 and python3 used.

No, that's not what the error message says:

> Could not load library "$libdir/plpython3"
> FATAL:  Python major version mismatch in session
> DETAIL:  This session has previously used Python major version 2, and it is 
> now attempting to use Python major version 3.
> HINT:  Start a new session to use a different Python major version.

This is a restriction we put in place because libpython2 and libpython3
don't coexist nicely in the same address space.  Unfortunately, it makes
it problematic to restore a dump that contains references to both python2
and python3 functions.

It looks like pg_upgrade tries to load all libraries from functions in
any database in the old cluster into a single session in the new cluster,
which will fail in a scenario like this even if you keep python2 and
python3 functions rigorously separated into distinct databases.  I'm
not sure if we could weaken that test enough to work.

> I dropped the python2 database but still got the problem.

You must still have at least one database that contains references
to python2 (check pg_language to be sure).

regards, tom lane


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