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Fix aboriginal mistake in plpython's set-returning-function support.

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We must stay in the function's SPI context until done calling the iterator
that returns the set result.  Otherwise, any attempt to invoke SPI features
in the python code called by the iterator will malfunction.  Diagnosis and
patch by Jan Urbanski, per bug report from Jean-Baptiste Quenot.

Back-patch to 8.2; there was no support for SRFs in previous versions of
plpython.
This commit is contained in:
Tom Lane 2010-11-15 14:26:55 -05:00
parent 3134d8863e
commit add0ea88e7
3 changed files with 48 additions and 8 deletions
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17
src/pl/plpython/expected/plpython_setof.out
View File

@ -31,6 +31,14 @@ class producer:
return self.icontent
return producer(count, content)
$$ LANGUAGE plpythonu;
CREATE FUNCTION test_setof_spi_in_iterator() RETURNS SETOF text AS
$$
for s in ('Hello', 'Brave', 'New', 'World'):
plpy.execute('select 1')
yield s
plpy.execute('select 2')
$$
LANGUAGE plpythonu;
-- Test set returning functions
SELECT test_setof_as_list(0, 'list');
test_setof_as_list
@ -107,3 +115,12 @@ SELECT test_setof_as_iterator(2, null);
(2 rows)
SELECT test_setof_spi_in_iterator();
test_setof_spi_in_iterator
----------------------------
Hello
Brave
New
World
(4 rows)

28
src/pl/plpython/plpython.c
View File

@ -985,7 +985,10 @@ PLy_function_handler(FunctionCallInfo fcinfo, PLyProcedure *proc)
{
if (!proc->is_setof || proc->setof == NULL)
{
/* Simple type returning function or first time for SETOF function */
/*
* Simple type returning function or first time for SETOF function:
* actually execute the function.
*/
plargs = PLy_function_build_args(fcinfo, proc);
plrv = PLy_procedure_call(proc, "args", plargs);
if (!proc->is_setof)
@ -1000,14 +1003,10 @@ PLy_function_handler(FunctionCallInfo fcinfo, PLyProcedure *proc)
}
/*
* Disconnect from SPI manager and then create the return values datum
* (if the input function does a palloc for it this must not be
* allocated in the SPI memory context because SPI_finish would free
* it).
* If it returns a set, call the iterator to get the next return item.
* We stay in the SPI context while doing this, because PyIter_Next()
* calls back into Python code which might contain SPI calls.
*/
if (SPI_finish() != SPI_OK_FINISH)
elog(ERROR, "SPI_finish failed");
if (proc->is_setof)
{
bool has_error = false;
@ -1064,11 +1063,24 @@ PLy_function_handler(FunctionCallInfo fcinfo, PLyProcedure *proc)
(errcode(ERRCODE_DATA_EXCEPTION),
errmsg("error fetching next item from iterator")));
/* Disconnect from the SPI manager before returning */
if (SPI_finish() != SPI_OK_FINISH)
elog(ERROR, "SPI_finish failed");
fcinfo->isnull = true;
return (Datum) NULL;
}
}
/*
* Disconnect from SPI manager and then create the return values datum
* (if the input function does a palloc for it this must not be
* allocated in the SPI memory context because SPI_finish would free
* it).
*/
if (SPI_finish() != SPI_OK_FINISH)
elog(ERROR, "SPI_finish failed");
plerrcontext.callback = plpython_return_error_callback;
plerrcontext.previous = error_context_stack;
error_context_stack = &plerrcontext;

11
src/pl/plpython/sql/plpython_setof.sql
View File

@ -35,6 +35,15 @@ class producer:
return producer(count, content)
$$ LANGUAGE plpythonu;
CREATE FUNCTION test_setof_spi_in_iterator() RETURNS SETOF text AS
$$
for s in ('Hello', 'Brave', 'New', 'World'):
plpy.execute('select 1')
yield s
plpy.execute('select 2')
$$
LANGUAGE plpythonu;
-- Test set returning functions
SELECT test_setof_as_list(0, 'list');
@ -51,3 +60,5 @@ SELECT test_setof_as_iterator(0, 'list');
SELECT test_setof_as_iterator(1, 'list');
SELECT test_setof_as_iterator(2, 'list');
SELECT test_setof_as_iterator(2, null);
SELECT test_setof_spi_in_iterator();