On Tue, Jan 20, 2015 at 3:34 PM, Peter Geoghegan <p...@heroku.com> wrote:
> On Tue, Jan 20, 2015 at 3:34 PM, Robert Haas <robertmh...@gmail.com> wrote:
>> Dear me. Peter, can you fix this RSN?
>
> Investigating.
It's certainly possible to fix Andrew's test case with the attached.
I'm not sure that that's the appropriate fix, though: there is
probably a case to be made for not bothering with abbreviation once
we've read tuples in for the final merge run. More likely, the
strongest case is for storing the abbreviated keys on disk too, and
reading those back.
--
Peter Geoghegan
diff --git a/src/backend/utils/sort/tuplesort.c b/src/backend/utils/sort/tuplesort.c
index 6d3aa88..adf4c4d 100644
--- a/src/backend/utils/sort/tuplesort.c
+++ b/src/backend/utils/sort/tuplesort.c
@@ -3148,6 +3148,7 @@ readtup_heap(Tuplesortstate *state, SortTuple *stup,
MinimalTuple tuple = (MinimalTuple) palloc(tuplen);
char *tupbody = (char *) tuple + MINIMAL_TUPLE_DATA_OFFSET;
HeapTupleData htup;
+ Datum original;
USEMEM(state, GetMemoryChunkSpace(tuple));
/* read in the tuple proper */
@@ -3161,10 +3162,29 @@ readtup_heap(Tuplesortstate *state, SortTuple *stup,
/* set up first-column key value */
htup.t_len = tuple->t_len + MINIMAL_TUPLE_OFFSET;
htup.t_data = (HeapTupleHeader) ((char *) tuple - MINIMAL_TUPLE_OFFSET);
- stup->datum1 = heap_getattr(&htup,
- state->sortKeys[0].ssup_attno,
- state->tupDesc,
- &stup->isnull1);
+ /* Once again, store abbreviated key representation */
+ original = heap_getattr(&htup,
+ state->sortKeys[0].ssup_attno,
+ state->tupDesc,
+ &stup->isnull1);
+
+ if (!state->sortKeys->abbrev_converter || stup->isnull1)
+ {
+ /*
+ * Store ordinary Datum representation, or NULL value. If there is a
+ * converter it won't expect NULL values, and cost model is not
+ * required to account for NULL, so in that case we avoid calling
+ * converter and just set datum1 to "void" representation (to be
+ * consistent).
+ */
+ stup->datum1 = original;
+ }
+ else
+ {
+ /* Store abbreviated key representation */
+ stup->datum1 = state->sortKeys->abbrev_converter(original,
+ state->sortKeys);
+ }
}
/*
--
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