diff options
Diffstat (limited to 'src/backend/utils/sort/tuplesort.c')
| -rw-r--r-- | src/backend/utils/sort/tuplesort.c | 22 |
1 files changed, 12 insertions, 10 deletions
diff --git a/src/backend/utils/sort/tuplesort.c b/src/backend/utils/sort/tuplesort.c index 041bdc2fa7e..e433faad86a 100644 --- a/src/backend/utils/sort/tuplesort.c +++ b/src/backend/utils/sort/tuplesort.c @@ -2147,12 +2147,13 @@ tuplesort_gettuple_common(Tuplesortstate *state, bool forward, * NULL value in leading attribute will set abbreviated value to zeroed * representation, which caller may rely on in abbreviated inequality check. * - * If copy is true, the slot receives a copied tuple that will stay valid - * regardless of future manipulations of the tuplesort's state. Memory is - * owned by the caller. If copy is false, the slot will just receive a - * pointer to a tuple held within the tuplesort, which is more efficient, but - * only safe for callers that are prepared to have any subsequent manipulation - * of the tuplesort's state invalidate slot contents. + * If copy is true, the slot receives a tuple that's been copied into the + * caller's memory context, so that it will stay valid regardless of future + * manipulations of the tuplesort's state (up to and including deleting the + * tuplesort). If copy is false, the slot will just receive a pointer to a + * tuple held within the tuplesort, which is more efficient, but only safe for + * callers that are prepared to have any subsequent manipulation of the + * tuplesort's state invalidate slot contents. */ bool tuplesort_gettupleslot(Tuplesortstate *state, bool forward, bool copy, @@ -2230,8 +2231,8 @@ tuplesort_getindextuple(Tuplesortstate *state, bool forward) * Returns false if no more datums. * * If the Datum is pass-by-ref type, the returned value is freshly palloc'd - * and is now owned by the caller (this differs from similar routines for - * other types of tuplesorts). + * in caller's context, and is now owned by the caller (this differs from + * similar routines for other types of tuplesorts). * * Caller may optionally be passed back abbreviated value (on true return * value) when abbreviation was used, which can be used to cheaply avoid @@ -2253,6 +2254,9 @@ tuplesort_getdatum(Tuplesortstate *state, bool forward, return false; } + /* Ensure we copy into caller's memory context */ + MemoryContextSwitchTo(oldcontext); + /* Record abbreviated key for caller */ if (state->sortKeys->abbrev_converter && abbrev) *abbrev = stup.datum1; @@ -2269,8 +2273,6 @@ tuplesort_getdatum(Tuplesortstate *state, bool forward, *isNull = false; } - MemoryContextSwitchTo(oldcontext); - return true; } |