Unexpected ER_DUP_KEY (1022): Can't write; duplicate key in table '(temporary)'

Important: I could only reproduce it on builds with CMAKE_BUILD_TYPE=RelWithDebInfo, but not with Debug. There might be some other factors that would make it not reproducible on some builds. For example, since the test case depends on the number of tables in I_S.TABLES, it may be not reproducible on builds which disable some plugins usually present in standard MTR runs.

The test case uses the extremely low value of max_heap_table_size=16K, so it may be considered an edge case unless it turns out to be scalable.

The use of a new database db is not important there, it's just for a more convenient cleanup.

SET max_heap_table_size = 16*1024;

CREATE DATABASE db;

USE db;

--let $run = 17

while ($run)

{

  --eval CREATE TEMPORARY TABLE t$run (a INT) ENGINE=MEMORY

  --dec $run

}

SELECT table_schema, table_name FROM INFORMATION_SCHEMA.TABLES

  WHERE engine NOT IN ( SELECT 'x' UNION SELECT 'xx' );

DROP DATABASE db;

mysqltest: At line 13: query 'SELECT table_schema, table_name FROM INFORMATION_SCHEMA.TABLES

WHERE engine NOT IN ( SELECT 'x' UNION SELECT 'xx' )' failed: ER_DUP_KEY (1022): Can't write; duplicate key in table '(temporary)'