-- hypothetical indexes using INCLUDE keyword, pg11+
-- Remove all the hypothetical indexes if any
SELECT hypopg_reset();
 hypopg_reset 
--------------
 
(1 row)

-- Make sure stats and visibility map are up to date
VACUUM ANALYZE hypo;
-- Should not use hypothetical index
-- Create normal index
SELECT COUNT(*) AS NB
FROM hypopg_create_index('CREATE INDEX ON hypo (id)');
 nb 
----
  1
(1 row)

-- Should use hypothetical index using a regular Index Scan
SELECT COUNT(*) FROM do_explain('SELECT val FROM hypo WHERE id = 1') e
WHERE e ~ 'Index Scan.*<\d+>btree_hypo.*';
 count 
-------
     1
(1 row)

-- Remove all the hypothetical indexes
SELECT hypopg_reset();
 hypopg_reset 
--------------
 
(1 row)

-- Create INCLUDE index
SELECT COUNT(*) AS NB
FROM hypopg_create_index('CREATE INDEX ON hypo (id) INCLUDE (val, "Id2")');
 nb 
----
  1
(1 row)

-- Should use hypothetical index using an Index Only Scan
SELECT COUNT(*) FROM do_explain('SELECT val FROM hypo WHERE id = 1') e
WHERE e ~ 'Index Only Scan.*<\d+>btree_hypo.*';
 count 
-------
     1
(1 row)

-- Deparse the index DDL
SELECT hypopg_get_indexdef(indexrelid) FROM hypopg();
                        hypopg_get_indexdef                        
-------------------------------------------------------------------
 CREATE INDEX ON public.hypo USING btree (id) INCLUDE (val, "Id2")
(1 row)

-- Check that indkey covers all attributes, while indcollations and indclass
-- only cover key columns
SELECT array_length(indkey, 1) = innatts
       AND array_length(indcollation, 1) = 1
       AND array_length(indclass, 1) = 1 AS key_vectors_match
FROM hypopg();
 key_vectors_match 
-------------------
 t
(1 row)