postgrespro.git / summary / log / commit / refs
commit 6bdc3005b54fc9c6ef27cd4e64edd548315f57ba
Author: Tom Lane <tgl@sss.pgh.pa.us>
Date: Mon Feb 11 03:51:32 2019 +0000
Fix indexable-row-comparison logic to account for covering indexes.
indxpath.c needs a good deal more attention for covering indexes than
it's gotten. But so far as I can tell, the only really awful breakage
is in expand_indexqual_rowcompare (nee adjust_rowcompare_for_index),
which was only half fixed in c266ed31a. The other problems aren't
bad enough to take the risk of a just-before-wrap fix.
The problem here is that if the leading column of a row comparison
matches an index (allowing this code to be reached), and some later
column doesn't match the index, it'll nonetheless believe that that
column matches the first included index column. Typically that'll
lead to an error like "operator M is not a member of opfamily N" as
a result of fetching a garbage opfamily OID. But with enough bad
luck, maybe a broken plan would be generated.
Discussion: https://postgr.es/m/25526.1549847928@sss.pgh.pa.us
src/backend/optimizer/path/indxpath.c | 4 ++--
src/test/regress/expected/index_including.out | 17 +++++++++++++++++
src/test/regress/sql/index_including.sql | 3 +++
3 files changed, 22 insertions(+), 2 deletions(-)
diff --git a/src/backend/optimizer/path/indxpath.c b/src/backend/optimizer/path/indxpath.c
index 51d2da5683..c03777ed60 100644
--- a/src/backend/optimizer/path/indxpath.c
+++ b/src/backend/optimizer/path/indxpath.c
@@ -3979,7 +3979,7 @@ expand_indexqual_rowcompare(RestrictInfo *rinfo,
break; /* no good, volatile comparison value */
/*
- * The Var side can match any column of the index.
+ * The Var side can match any key column of the index.
*/
for (i = 0; i < index->nkeycolumns; i++)
{
@@ -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 */
diff --git a/src/test/regress/expected/index_including.out b/src/test/regress/expected/index_including.out
index 16b4be34de..f86e5953fa 100644
--- a/src/test/regress/expected/index_including.out
+++ b/src/test/regress/expected/index_including.out
@@ -127,6 +127,23 @@ INSERT INTO tbl SELECT 1, NULL, 3*x, box('4,4,4,4') FROM generate_series(1,10) A
ERROR: null value in column "c2" violates not-null constraint
DETAIL: Failing row contains (1, null, 3, (4,4),(4,4)).
INSERT INTO tbl SELECT x, 2*x, NULL, NULL FROM generate_series(1,10) AS x;
+explain (costs off)
+select * from tbl where (c1,c2,c3) < (2,5,1);
+ QUERY PLAN
+------------------------------------------------
+ Bitmap Heap Scan on tbl
+ Filter: (ROW(c1, c2, c3) < ROW(2, 5, 1))
+ -> Bitmap Index Scan on covering
+ Index Cond: (ROW(c1, c2) <= ROW(2, 5))
+(4 rows)
+
+select * from tbl where (c1,c2,c3) < (2,5,1);
+ c1 | c2 | c3 | c4
+----+----+----+----
+ 1 | 2 | |
+ 2 | 4 | |
+(2 rows)
+
DROP TABLE tbl;
CREATE TABLE tbl (c1 int,c2 int, c3 int, c4 box,
UNIQUE(c1,c2) INCLUDE(c3,c4));
diff --git a/src/test/regress/sql/index_including.sql b/src/test/regress/sql/index_including.sql
index ef5fd882f5..2c6dd6211e 100644
--- a/src/test/regress/sql/index_including.sql
+++ b/src/test/regress/sql/index_including.sql
@@ -73,6 +73,9 @@ SELECT pg_get_constraintdef(oid), conname, conkey FROM pg_constraint WHERE conre
INSERT INTO tbl SELECT 1, 2, 3*x, box('4,4,4,4') FROM generate_series(1,10) AS x;
INSERT INTO tbl SELECT 1, NULL, 3*x, box('4,4,4,4') FROM generate_series(1,10) AS x;
INSERT INTO tbl SELECT x, 2*x, NULL, NULL FROM generate_series(1,10) AS x;
+explain (costs off)
+select * from tbl where (c1,c2,c3) < (2,5,1);
+select * from tbl where (c1,c2,c3) < (2,5,1);
DROP TABLE tbl;
CREATE TABLE tbl (c1 int,c2 int, c3 int, c4 box,
[parent: 72d71e03563b]