Apparently, whoever went through indxpath.c to substitute nkeycolumns
for ncolumns was not paying attention. As far as I can tell, the
*only* place in there where it's correct to reference ncolumns is in
check_index_only, where we determine which columns can be extracted from
an index-only scan. A lot of the other places are obviously wrong, eg in
relation_has_unique_index_for:
for (c = 0; c < ind->ncolumns; c++)
...
if (!list_member_oid(rinfo->mergeopfamilies, ind->opfamily[c]))
Even if it were plausible that an INCLUDE column is something to consider
when deciding whether the index enforces uniqueness, this code accesses
beyond the documented end of the opfamily[] array :-(
The fact that the regression tests haven't caught this doesn't give
me a warm feeling about how thoroughly the included-columns logic has
been tested. It's really easy to make it fall over, for instance
regression=# explain select * from tenk1 where (thousand, tenthous) < (10,100);
QUERY PLAN
--------------------------------------------------------------------------------
-----
Bitmap Heap Scan on tenk1 (cost=5.11..233.86 rows=107 width=244)
Recheck Cond: (ROW(thousand, tenthous) < ROW(10, 100))
-> Bitmap Index Scan on tenk1_thous_tenthous (cost=0.00..5.09 rows=107 widt
h=0)
Index Cond: (ROW(thousand, tenthous) < ROW(10, 100))
(4 rows)
regression=# drop index tenk1_thous_tenthous;
DROP INDEX
regression=# create index on tenk1(thousand) include (tenthous);
CREATE INDEX
regression=# explain select * from tenk1 where (thousand, tenthous) < (10,100);
ERROR: operator 97 is not a member of opfamily 2139062142
I've got mixed feelings about whether to try to fix this before
tomorrow's wraps. The attached patch seems correct and passes
check-world, but there's sure not a lot of margin for error now.
Thoughts?
regards, tom lane
diff --git a/src/backend/optimizer/path/indxpath.c b/src/backend/optimizer/path/indxpath.c
index 51d2da5..a55b9e0 100644
--- a/src/backend/optimizer/path/indxpath.c
+++ b/src/backend/optimizer/path/indxpath.c
@@ -258,7 +258,7 @@ create_index_paths(PlannerInfo *root, RelOptInfo *rel)
IndexOptInfo *index = (IndexOptInfo *) lfirst(lc);
/* Protect limited-size array in IndexClauseSets */
- Assert(index->ncolumns <= INDEX_MAX_KEYS);
+ Assert(index->nkeycolumns <= INDEX_MAX_KEYS);
/*
* Ignore partial indexes that do not match the query.
@@ -473,7 +473,7 @@ consider_index_join_clauses(PlannerInfo *root, RelOptInfo *rel,
* relation itself is also included in the relids set. considered_relids
* lists all relids sets we've already tried.
*/
- for (indexcol = 0; indexcol < index->ncolumns; indexcol++)
+ for (indexcol = 0; indexcol < index->nkeycolumns; indexcol++)
{
/* Consider each applicable simple join clause */
considered_clauses += list_length(jclauseset->indexclauses[indexcol]);
@@ -628,7 +628,7 @@ get_join_index_paths(PlannerInfo *root, RelOptInfo *rel,
/* Identify indexclauses usable with this relids set */
MemSet(&clauseset, 0, sizeof(clauseset));
- for (indexcol = 0; indexcol < index->ncolumns; indexcol++)
+ for (indexcol = 0; indexcol < index->nkeycolumns; indexcol++)
{
ListCell *lc;
@@ -925,7 +925,7 @@ build_index_paths(PlannerInfo *root, RelOptInfo *rel,
index_clauses = NIL;
found_lower_saop_clause = false;
outer_relids = bms_copy(rel->lateral_relids);
- for (indexcol = 0; indexcol < index->ncolumns; indexcol++)
+ for (indexcol = 0; indexcol < index->nkeycolumns; indexcol++)
{
ListCell *lc;
@@ -2680,7 +2680,7 @@ match_pathkeys_to_index(IndexOptInfo *index, List *pathkeys,
* amcanorderbyop. We might need different logic in future for
* other implementations.
*/
- for (indexcol = 0; indexcol < index->ncolumns; indexcol++)
+ for (indexcol = 0; indexcol < index->nkeycolumns; indexcol++)
{
Expr *expr;
@@ -3111,7 +3111,7 @@ relation_has_unique_index_for(PlannerInfo *root, RelOptInfo *rel,
* Try to find each index column in the lists of conditions. This is
* O(N^2) or worse, but we expect all the lists to be short.
*/
- for (c = 0; c < ind->ncolumns; c++)
+ for (c = 0; c < ind->nkeycolumns; c++)
{
bool matched = false;
ListCell *lc;
@@ -3187,7 +3187,7 @@ relation_has_unique_index_for(PlannerInfo *root, RelOptInfo *rel,
}
/* Matched all columns of this index? */
- if (c == ind->ncolumns)
+ if (c == ind->nkeycolumns)
return true;
}
@@ -3991,7 +3991,7 @@ expand_indexqual_rowcompare(RestrictInfo *rinfo,
break;
}
- if (i >= index->ncolumns)
+ if (i >= index->nkeycolumns)
break; /* no match found */
/* Add column number to returned list */
