Here's a patch implementing a executing SPI in an subtransaction
mentioned in
http://archives.postgresql.org/pgsql-hackers/2010-12/msg01991.php. It's
an incremental patch on top of the plpython-refactor patch sent eariler.
Git branch for this patch:
https://github.com/wulczer/postgres/tree/spi-in-subxacts.
Without it the error handling in PL/Python is really broken, as we jump
between from a saught longjmp back into Python without any cleanup. As
an additional bonus you no longer get all the ugly "unrecognized error
in PLy_spi_execute_query" errors.
Cheers,
Jan
diff --git a/src/pl/plpython/expected/plpython_error.out b/src/pl/plpython/expected/plpython_error.out
index 70890a8..7fc8337 100644
*** a/src/pl/plpython/expected/plpython_error.out
--- b/src/pl/plpython/expected/plpython_error.out
*************** CREATE FUNCTION sql_syntax_error() RETUR
*** 8,15 ****
'plpy.execute("syntax error")'
LANGUAGE plpythonu;
SELECT sql_syntax_error();
- WARNING: plpy.SPIError: unrecognized error in PLy_spi_execute_query
- CONTEXT: PL/Python function "sql_syntax_error"
ERROR: plpy.SPIError: syntax error at or near "syntax"
CONTEXT: PL/Python function "sql_syntax_error"
/* check the handling of uncaught python exceptions
--- 8,13 ----
*************** CREATE FUNCTION exception_index_invalid_
*** 29,36 ****
return rv[0]'
LANGUAGE plpythonu;
SELECT exception_index_invalid_nested();
- WARNING: plpy.SPIError: unrecognized error in PLy_spi_execute_query
- CONTEXT: PL/Python function "exception_index_invalid_nested"
ERROR: plpy.SPIError: function test5(unknown) does not exist
CONTEXT: PL/Python function "exception_index_invalid_nested"
/* a typo
--- 27,32 ----
*************** return None
*** 47,54 ****
'
LANGUAGE plpythonu;
SELECT invalid_type_uncaught('rick');
- WARNING: plpy.SPIError: unrecognized error in PLy_spi_prepare
- CONTEXT: PL/Python function "invalid_type_uncaught"
ERROR: plpy.SPIError: type "test" does not exist
CONTEXT: PL/Python function "invalid_type_uncaught"
/* for what it's worth catch the exception generated by
--- 43,48 ----
*************** return None
*** 70,77 ****
'
LANGUAGE plpythonu;
SELECT invalid_type_caught('rick');
- WARNING: plpy.SPIError: unrecognized error in PLy_spi_prepare
- CONTEXT: PL/Python function "invalid_type_caught"
NOTICE: type "test" does not exist
CONTEXT: PL/Python function "invalid_type_caught"
invalid_type_caught
--- 64,69 ----
*************** return None
*** 97,104 ****
'
LANGUAGE plpythonu;
SELECT invalid_type_reraised('rick');
- WARNING: plpy.SPIError: unrecognized error in PLy_spi_prepare
- CONTEXT: PL/Python function "invalid_type_reraised"
ERROR: plpy.Error: type "test" does not exist
CONTEXT: PL/Python function "invalid_type_reraised"
/* no typo no messing about
--- 89,94 ----
diff --git a/src/pl/plpython/plpython.c b/src/pl/plpython/plpython.c
index 67eb0f3..5b216b2 100644
*** a/src/pl/plpython/plpython.c
--- b/src/pl/plpython/plpython.c
*************** typedef int Py_ssize_t;
*** 101,106 ****
--- 101,107 ----
#include "nodes/makefuncs.h"
#include "parser/parse_type.h"
#include "tcop/tcopprot.h"
+ #include "access/xact.h"
#include "utils/builtins.h"
#include "utils/lsyscache.h"
#include "utils/memutils.h"
*************** PLy_spi_prepare(PyObject *self, PyObject
*** 2829,2834 ****
--- 2830,2836 ----
int nargs;
MemoryContext volatile oldcontext = CurrentMemoryContext;
+ ResourceOwner volatile oldowner = CurrentResourceOwner;
if (!PyArg_ParseTuple(args, "s|O", &query, &list))
{
*************** PLy_spi_prepare(PyObject *self, PyObject
*** 2852,2857 ****
--- 2854,2862 ----
plan->values = PLy_malloc(sizeof(Datum) * nargs);
plan->args = PLy_malloc(sizeof(PLyTypeInfo) * nargs);
+ BeginInternalSubTransaction(NULL);
+ MemoryContextSwitchTo(oldcontext);
+
PG_TRY();
{
int i;
*************** PLy_spi_prepare(PyObject *self, PyObject
*** 2931,2949 ****
if (plan->plan == NULL)
elog(ERROR, "SPI_saveplan failed: %s",
SPI_result_code_string(SPI_result));
}
PG_CATCH();
{
ErrorData *edata;
- MemoryContextSwitchTo(oldcontext);
- edata = CopyErrorData();
Py_DECREF(plan);
Py_XDECREF(optr);
! if (!PyErr_Occurred())
! PLy_exception_set(PLy_exc_spi_error,
! "unrecognized error in PLy_spi_prepare");
! PLy_elog(WARNING, NULL);
PLy_exception_set(PLy_exc_spi_error, edata->message);
return NULL;
}
--- 2936,2978 ----
if (plan->plan == NULL)
elog(ERROR, "SPI_saveplan failed: %s",
SPI_result_code_string(SPI_result));
+
+ /* Commit the inner transaction, return to outer xact context */
+ ReleaseCurrentSubTransaction();
+ MemoryContextSwitchTo(oldcontext);
+ CurrentResourceOwner = oldowner;
+
+ /*
+ * AtEOSubXact_SPI() should not have popped any SPI context, but just
+ * in case it did, make sure we remain connected.
+ */
+ SPI_restore_connection();
}
PG_CATCH();
{
ErrorData *edata;
Py_DECREF(plan);
Py_XDECREF(optr);
!
! /* Save error info */
! MemoryContextSwitchTo(oldcontext);
! edata = CopyErrorData();
! FlushErrorState();
!
! /* Abort the inner transaction */
! RollbackAndReleaseCurrentSubTransaction();
! MemoryContextSwitchTo(oldcontext);
! CurrentResourceOwner = oldowner;
!
! /*
! * If AtEOSubXact_SPI() popped any SPI context of the subxact, it
! * will have left us in a disconnected state. We need this hack to
! * return to connected state.
! */
! SPI_restore_connection();
!
! /* Make Python raise the exception */
PLy_exception_set(PLy_exc_spi_error, edata->message);
return NULL;
}
*************** PLy_spi_execute_plan(PyObject *ob, PyObj
*** 2985,2990 ****
--- 3014,3020 ----
PLyPlanObject *plan;
PyObject *ret;
MemoryContext volatile oldcontext = CurrentMemoryContext;
+ ResourceOwner volatile oldowner = CurrentResourceOwner;
if (list != NULL)
{
*************** PLy_spi_execute_plan(PyObject *ob, PyObj
*** 3018,3023 ****
--- 3048,3057 ----
return NULL;
}
+ BeginInternalSubTransaction(NULL);
+ /* Want to run inside function's memory context */
+ MemoryContextSwitchTo(oldcontext);
+
PG_TRY();
{
char *nulls;
*************** PLy_spi_execute_plan(PyObject *ob, PyObj
*** 3071,3082 ****
--- 3105,3126 ----
if (nargs > 0)
pfree(nulls);
+ /* Commit the inner transaction, return to outer xact context */
+ ReleaseCurrentSubTransaction();
+ MemoryContextSwitchTo(oldcontext);
+ CurrentResourceOwner = oldowner;
+ /*
+ * AtEOSubXact_SPI() should not have popped any SPI context, but just
+ * in case it did, make sure we remain connected.
+ */
+ SPI_restore_connection();
}
PG_CATCH();
{
ErrorData *edata;
+ /* Save error info */
MemoryContextSwitchTo(oldcontext);
edata = CopyErrorData();
FlushErrorState();
*************** PLy_spi_execute_plan(PyObject *ob, PyObj
*** 3094,3103 ****
}
}
! if (!PyErr_Occurred())
! PLy_exception_set(PLy_exc_spi_error,
! "unrecognized error in PLy_spi_execute_plan");
! PLy_elog(WARNING, NULL);
PLy_exception_set(PLy_exc_spi_error, edata->message);
return NULL;
}
--- 3138,3156 ----
}
}
! /* Abort the inner transaction */
! RollbackAndReleaseCurrentSubTransaction();
! MemoryContextSwitchTo(oldcontext);
! CurrentResourceOwner = oldowner;
!
! /*
! * If AtEOSubXact_SPI() popped any SPI context of the subxact, it
! * will have left us in a disconnected state. We need this hack to
! * return to connected state.
! */
! SPI_restore_connection();
!
! /* Make Python raise the exception */
PLy_exception_set(PLy_exc_spi_error, edata->message);
return NULL;
}
*************** PLy_spi_execute_query(char *query, long
*** 3122,3158 ****
int rv;
PyObject *ret;
MemoryContext volatile oldcontext = CurrentMemoryContext;
PG_TRY();
{
pg_verifymbstr(query, strlen(query), false);
rv = SPI_execute(query, PLy_curr_procedure->fn_readonly, limit);
ret = PLy_spi_execute_fetch_result(SPI_tuptable, SPI_processed, rv);
}
PG_CATCH();
{
ErrorData *edata;
MemoryContextSwitchTo(oldcontext);
edata = CopyErrorData();
FlushErrorState();
! if (!PyErr_Occurred())
! PLy_exception_set(PLy_exc_spi_error,
! "unrecognized error in PLy_spi_execute_query");
! PLy_elog(WARNING, NULL);
PLy_exception_set(PLy_exc_spi_error, edata->message);
return NULL;
}
PG_END_TRY();
- if (rv < 0)
- {
- PLy_exception_set(PLy_exc_spi_error,
- "SPI_execute failed: %s",
- SPI_result_code_string(rv));
- return NULL;
- }
-
return ret;
}
--- 3175,3234 ----
int rv;
PyObject *ret;
MemoryContext volatile oldcontext = CurrentMemoryContext;
+ ResourceOwner volatile oldowner = CurrentResourceOwner;
+
+ /*
+ * Execute the query inside a sub-transaction, so we can cope with errors
+ * sanely
+ */
+ BeginInternalSubTransaction(NULL);
+ /* Want to run inside function's memory context */
+ MemoryContextSwitchTo(oldcontext);
PG_TRY();
{
pg_verifymbstr(query, strlen(query), false);
rv = SPI_execute(query, PLy_curr_procedure->fn_readonly, limit);
ret = PLy_spi_execute_fetch_result(SPI_tuptable, SPI_processed, rv);
+
+ /* Commit the inner transaction, return to outer xact context */
+ ReleaseCurrentSubTransaction();
+ MemoryContextSwitchTo(oldcontext);
+ CurrentResourceOwner = oldowner;
+
+ /*
+ * AtEOSubXact_SPI() should not have popped any SPI context, but just
+ * in case it did, make sure we remain connected.
+ */
+ SPI_restore_connection();
}
PG_CATCH();
{
ErrorData *edata;
+ /* Save error info */
MemoryContextSwitchTo(oldcontext);
edata = CopyErrorData();
FlushErrorState();
!
! /* Abort the inner transaction */
! RollbackAndReleaseCurrentSubTransaction();
! MemoryContextSwitchTo(oldcontext);
! CurrentResourceOwner = oldowner;
!
! /*
! * If AtEOSubXact_SPI() popped any SPI context of the subxact, it
! * will have left us in a disconnected state. We need this hack to
! * return to connected state.
! */
! SPI_restore_connection();
!
! /* Make Python raise the exception */
PLy_exception_set(PLy_exc_spi_error, edata->message);
return NULL;
}
PG_END_TRY();
return ret;
}
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