diff options
Diffstat (limited to 'src/backend/utils')
| -rw-r--r-- | src/backend/utils/sort/tuplesort.c | 79 |
1 files changed, 49 insertions, 30 deletions
diff --git a/src/backend/utils/sort/tuplesort.c b/src/backend/utils/sort/tuplesort.c index 1d0ed4e9f2..be80b246a2 100644 --- a/src/backend/utils/sort/tuplesort.c +++ b/src/backend/utils/sort/tuplesort.c @@ -78,7 +78,7 @@ * Portions Copyright (c) 1994, Regents of the University of California * * IDENTIFICATION - * $Header: /cvsroot/pgsql/src/backend/utils/sort/tuplesort.c,v 1.5 2000/01/26 05:57:33 momjian Exp $ + * $Header: /cvsroot/pgsql/src/backend/utils/sort/tuplesort.c,v 1.6 2000/02/18 06:32:30 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -253,6 +253,7 @@ struct Tuplesortstate * by tuplesort_begin_index and used only by the IndexTuple routines. */ Relation indexRel; + ScanKey indexScanKey; bool enforceUnique; /* complain if we find duplicate tuples */ /* @@ -476,6 +477,8 @@ tuplesort_begin_index(Relation indexRel, state->tuplesize = tuplesize_index; state->indexRel = indexRel; + /* see comments below about btree dependence of this code... */ + state->indexScanKey = _bt_mkscankey_nodata(indexRel); state->enforceUnique = enforceUnique; return state; @@ -1745,40 +1748,56 @@ tuplesize_heap(Tuplesortstate *state, void *tup) static int comparetup_index(Tuplesortstate *state, const void *a, const void *b) { - IndexTuple ltup = (IndexTuple) a; - IndexTuple rtup = (IndexTuple) b; - TupleDesc itdesc = state->indexRel->rd_att; - bool equal_isnull = false; + /* + * This is almost the same as _bt_tuplecompare(), but we need to + * keep track of whether any null fields are present. + */ + IndexTuple tuple1 = (IndexTuple) a; + IndexTuple tuple2 = (IndexTuple) b; + Relation rel = state->indexRel; + Size keysz = RelationGetNumberOfAttributes(rel); + ScanKey scankey = state->indexScanKey; + TupleDesc tupDes; int i; + bool equal_hasnull = false; - for (i = 1; i <= itdesc->natts; i++) - { - Datum lattr, - rattr; - bool isnull1, - isnull2; - - lattr = index_getattr(ltup, i, itdesc, &isnull1); - rattr = index_getattr(rtup, i, itdesc, &isnull2); + tupDes = RelationGetDescr(rel); - if (isnull1) + for (i = 1; i <= keysz; i++) + { + ScanKey entry = &scankey[i - 1]; + Datum attrDatum1, + attrDatum2; + bool isFirstNull, + isSecondNull; + int32 compare; + + attrDatum1 = index_getattr(tuple1, i, tupDes, &isFirstNull); + attrDatum2 = index_getattr(tuple2, i, tupDes, &isSecondNull); + + /* see comments about NULLs handling in btbuild */ + if (isFirstNull) /* attr in tuple1 is NULL */ { - if (!isnull2) - return 1; /* NULL sorts after non-NULL */ - equal_isnull = true; - continue; + if (isSecondNull) /* attr in tuple2 is NULL too */ + { + compare = 0; + equal_hasnull = true; + } + else + compare = 1; /* NULL ">" not-NULL */ + } + else if (isSecondNull) /* attr in tuple1 is NOT_NULL and */ + { /* attr in tuple2 is NULL */ + compare = -1; /* not-NULL "<" NULL */ + } + else + { + compare = (int32) FMGR_PTR2(&entry->sk_func, + attrDatum1, attrDatum2); } - else if (isnull2) - return -1; - if (_bt_invokestrat(state->indexRel, i, - BTGreaterStrategyNumber, - lattr, rattr)) - return 1; - if (_bt_invokestrat(state->indexRel, i, - BTGreaterStrategyNumber, - rattr, lattr)) - return -1; + if (compare != 0) + return (int) compare; /* done when we find unequal attributes */ } /* @@ -1790,7 +1809,7 @@ comparetup_index(Tuplesortstate *state, const void *a, const void *b) * the sort algorithm wouldn't have checked whether one must appear * before the other. */ - if (state->enforceUnique && !equal_isnull) + if (state->enforceUnique && !equal_hasnull) elog(ERROR, "Cannot create unique index. Table contains non-unique values"); return 0; |