From add0ea88e7722b48d1f3a7c38e3cfd7f1e854674 Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Mon, 15 Nov 2010 14:26:55 -0500 Subject: [PATCH] Fix aboriginal mistake in plpython's set-returning-function support. 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. --- src/pl/plpython/expected/plpython_setof.out | 17 +++++++++++++ src/pl/plpython/plpython.c | 28 +++++++++++++++------ src/pl/plpython/sql/plpython_setof.sql | 11 ++++++++ 3 files changed, 48 insertions(+), 8 deletions(-) diff --git a/src/pl/plpython/expected/plpython_setof.out b/src/pl/plpython/expected/plpython_setof.out index ebf896df01..ac9765fc88 100644 --- a/src/pl/plpython/expected/plpython_setof.out +++ b/src/pl/plpython/expected/plpython_setof.out @@ -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) + diff --git a/src/pl/plpython/plpython.c b/src/pl/plpython/plpython.c index f3352b3bc6..1ae12396a1 100644 --- a/src/pl/plpython/plpython.c +++ b/src/pl/plpython/plpython.c @@ -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; diff --git a/src/pl/plpython/sql/plpython_setof.sql b/src/pl/plpython/sql/plpython_setof.sql index 53d91a9e7d..80a8d5b4c1 100644 --- a/src/pl/plpython/sql/plpython_setof.sql +++ b/src/pl/plpython/sql/plpython_setof.sql @@ -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(); -- 2.40.0