From 0a34bcd0c23e7f67daad7b026320a12c52d797ac Mon Sep 17 00:00:00 2001 From: David Rowley Date: Wed, 1 May 2024 13:23:05 +1200 Subject: Ensure we allocate NAMEDATALEN bytes for names in Index Only Scans As an optimization, we store "name" columns as cstrings in btree indexes. Here we modify it so that Index Only Scans convert these cstrings back to names with NAMEDATALEN bytes rather than storing the cstring in the tuple slot, as was happening previously. Bug: #17855 Reported-by: Alexander Lakhin Reviewed-by: Alexander Lakhin, Tom Lane Discussion: https://postgr.es/m/17855-5f523e0f9769a566@postgresql.org Backpatch-through: 12, all supported versions --- src/test/regress/expected/index_including.out | 25 +++++++++++++++++++++++++ src/test/regress/sql/index_including.sql | 19 +++++++++++++++++++ 2 files changed, 44 insertions(+) (limited to 'src/test') diff --git a/src/test/regress/expected/index_including.out b/src/test/regress/expected/index_including.out index 8e5d53e712a..4aacf355821 100644 --- a/src/test/regress/expected/index_including.out +++ b/src/test/regress/expected/index_including.out @@ -399,3 +399,28 @@ Indexes: "tbl_c1_c2_c3_c4_key" UNIQUE CONSTRAINT, btree (c1, c2) INCLUDE (c3, c4) DROP TABLE tbl; +/* + * 10. Test coverage for names stored as cstrings in indexes + */ +CREATE TABLE nametbl (c1 int, c2 name, c3 float); +CREATE INDEX nametbl_c1_c2_idx ON nametbl (c2, c1) INCLUDE (c3); +INSERT INTO nametbl VALUES(1, 'two', 3.0); +VACUUM nametbl; +SET enable_seqscan = 0; +-- Ensure we get an index only scan plan +EXPLAIN (COSTS OFF) SELECT c2, c1, c3 FROM nametbl WHERE c2 = 'two' AND c1 = 1; + QUERY PLAN +---------------------------------------------------- + Index Only Scan using nametbl_c1_c2_idx on nametbl + Index Cond: ((c2 = 'two'::name) AND (c1 = 1)) +(2 rows) + +-- Validate the results look sane +SELECT c2, c1, c3 FROM nametbl WHERE c2 = 'two' AND c1 = 1; + c2 | c1 | c3 +-----+----+---- + two | 1 | 3 +(1 row) + +RESET enable_seqscan; +DROP TABLE nametbl; diff --git a/src/test/regress/sql/index_including.sql b/src/test/regress/sql/index_including.sql index 7e517483adf..880f4bbc421 100644 --- a/src/test/regress/sql/index_including.sql +++ b/src/test/regress/sql/index_including.sql @@ -217,3 +217,22 @@ ALTER TABLE tbl ALTER c1 TYPE bigint; ALTER TABLE tbl ALTER c3 TYPE bigint; \d tbl DROP TABLE tbl; + +/* + * 10. Test coverage for names stored as cstrings in indexes + */ +CREATE TABLE nametbl (c1 int, c2 name, c3 float); +CREATE INDEX nametbl_c1_c2_idx ON nametbl (c2, c1) INCLUDE (c3); +INSERT INTO nametbl VALUES(1, 'two', 3.0); +VACUUM nametbl; +SET enable_seqscan = 0; + +-- Ensure we get an index only scan plan +EXPLAIN (COSTS OFF) SELECT c2, c1, c3 FROM nametbl WHERE c2 = 'two' AND c1 = 1; + +-- Validate the results look sane +SELECT c2, c1, c3 FROM nametbl WHERE c2 = 'two' AND c1 = 1; + +RESET enable_seqscan; + +DROP TABLE nametbl; \ No newline at end of file -- cgit v1.2.3