postgresql/contrib/ltree_plpython/ltree_plpythonu--1.0.sql
Tom Lane fb6fcbd33f Use LOAD not actual code execution to pull in plpython library.
Commit 866566a690 is insufficient to prevent dump/reload failures
when using transform modules in a database with both plpython2 and
plpython3 installed.  The reason is that the transform extension scripts
use DO blocks as a mechanism to pull in the libpython library before
creating the transform function.  It's necessary to preload the library
because the dynamic loader won't do it for us on every platform, leading
to "unresolved symbol" failures when the transform library is loaded.
But it's *not* necessary to execute Python code, and doing so will
provoke a multiple-Pythons-are-loaded error even after the preceding
commit.

To fix, use LOAD instead of a DO block.  That requires superuser privilege,
but creation of a C function does anyway.  It also embeds knowledge of
the underlying library name for each PL language; but that's wired into
the initdb-time contents of pg_pltemplate too, so that doesn't seem like
a large problem either.  Note that CREATE TRANSFORM as such doesn't call
the language module at all.

Per a report from Paul Jones.  Back-patch to 9.5 where transform modules
were introduced.
2016-01-11 20:06:36 -05:00

13 lines
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SQL

-- make sure the prerequisite libraries are loaded
LOAD 'plpython2'; -- change to plpython3 if that ever becomes the default
SELECT NULL::ltree;
CREATE FUNCTION ltree_to_plpython(val internal) RETURNS internal
LANGUAGE C STRICT IMMUTABLE
AS 'MODULE_PATHNAME';
CREATE TRANSFORM FOR ltree LANGUAGE plpythonu (
FROM SQL WITH FUNCTION ltree_to_plpython(internal)
);