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  1. MariaDB Server
  2. MDEV-18941

HEAP index is no longer used

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      There is a repeatable test failure that was introduced by the MDEV-18922 fix:

      CURRENT_TEST: heap.heap_hash
      --- /mariadb/10.4/mysql-test/suite/heap/heap_hash.result	2019-03-15 18:06:34.123298015 +0200
      +++ /mariadb/10.4/mysql-test/suite/heap/heap_hash.reject	2019-03-15 18:08:34.912797504 +0200
      @@ -66,7 +66,7 @@
       alter table t1 engine=myisam;
       explain select * from t1 where a in (869751,736494,226312,802616);
       id	select_type	table	type	possible_keys	key	key_len	ref	rows	Extra
      -1	SIMPLE	t1	index	uniq_id	uniq_id	8	NULL	5	Using where; Using index
      +1	SIMPLE	t1	ALL	uniq_id	NULL	NULL	NULL	5	Using where
       drop table t1;
       create table t1 (x int not null, y int not null, key x  using HASH (x), unique y  using HASH (y))
       engine=heap;
       
      mysqltest: Result length mismatch
      

      This line was last modified by MDEV-371, but it only replaced 4 with the 8 that is now being removed. After the MDEV-19822 fix, we are no longer "Using index". This looks like a potential performance regression for storage engines that support heap indexes.

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              sachin.setiya.007 Sachin Setiya (Inactive)
              marko Marko Mäkelä
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