Add bool GiST opclass to btree_gist

Adds bool opclass to btree_gist extension, to allow creating GiST
indexes on bool columns. GiST indexes on a single bool column don't seem
particularly useful, but this allows defining exclusion constraings
involving a bool column, for example.

Author: Emre Hasegeli
Reviewed-by: Andrey Borodin
Discussion: https://postgr.es/m/CAE2gYzyDKJBZngssR84VGZEN=Ux=V9FV23QfPgo+7-yYnKKg4g@mail.gmail.com

1 files changed, 42 insertions, 0 deletions

diff --git a/contrib/btree_gist/sql/bool.sql b/contrib/btree_gist/sql/bool.sql
new file mode 100644
index 00000000000..4c2a5392b6c
--- /dev/null
+++ b/contrib/btree_gist/sql/bool.sql
@@ -0,0 +1,42 @@
+-- bool check
+
+CREATE TABLE booltmp (a bool);
+
+INSERT INTO booltmp VALUES (false), (true);
+
+SET enable_seqscan=on;
+
+SELECT count(*) FROM booltmp WHERE a <  true;
+
+SELECT count(*) FROM booltmp WHERE a <= true;
+
+SELECT count(*) FROM booltmp WHERE a  = true;
+
+SELECT count(*) FROM booltmp WHERE a >= true;
+
+SELECT count(*) FROM booltmp WHERE a >  true;
+
+CREATE INDEX boolidx ON booltmp USING gist ( a );
+
+SET enable_seqscan=off;
+
+SELECT count(*) FROM booltmp WHERE a <  true;
+
+SELECT count(*) FROM booltmp WHERE a <= true;
+
+SELECT count(*) FROM booltmp WHERE a  = true;
+
+SELECT count(*) FROM booltmp WHERE a >= true;
+
+SELECT count(*) FROM booltmp WHERE a >  true;
+
+-- Test index-only scans
+SET enable_bitmapscan=off;
+
+EXPLAIN (COSTS OFF)
+SELECT * FROM booltmp WHERE a;
+SELECT * FROM booltmp WHERE a;
+
+EXPLAIN (COSTS OFF)
+SELECT * FROM booltmp WHERE NOT a;
+SELECT * FROM booltmp WHERE NOT a;