
Commit 866566a690bb9916 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.
13 lines
370 B
SQL
13 lines
370 B
SQL
-- make sure the prerequisite libraries are loaded
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LOAD 'plpython2'; -- change to plpython3 if that ever becomes the default
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SELECT NULL::ltree;
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CREATE FUNCTION ltree_to_plpython(val internal) RETURNS internal
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LANGUAGE C STRICT IMMUTABLE
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AS 'MODULE_PATHNAME';
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CREATE TRANSFORM FOR ltree LANGUAGE plpythonu (
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FROM SQL WITH FUNCTION ltree_to_plpython(internal)
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);
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