Hi folks, While reading on some material on MySql and indexing I came across $subject. In our DB scripts we use hash indexes with Innodb engine right ?! According to mysql docs [1];
============================================ Some storage engines permit you to specify an index type when creating an index. The permissible index type values supported by different storage engines are shown in the following table. Where multiple index types are listed, the first one is the default when no index type specifier is given. Storage Engine Permissible Index Types InnoDB<http://dev.mysql.com/doc/refman/5.6/en/innodb-storage-engine.html> BTREE MyISAM<http://dev.mysql.com/doc/refman/5.6/en/myisam-storage-engine.html> BTREE MEMORY<http://dev.mysql.com/doc/refman/5.6/en/memory-storage-engine.html> /HEAP HASH, BTREE NDB<http://dev.mysql.com/doc/refman/5.5/en/mysql-cluster.html> HASH, BTREE (see note in text) If you specify an index type that is not valid for a given storage engine, but there is another index type available that the engine can use without affecting query results, the engine uses the available type. The parser recognizesRTREE as a type name, but currently this cannot be specified for any storage engine. ============================================ According to the second section, I wonder if mysql silently converts the indexes to BTREE even though we specify it as Hash?! I am totally new to database indexes so please correct me if I have misunderstood the whole subject matter :) [1] - http://dev.mysql.com/doc/refman/5.6/en/create-index.html -- Thanks, Shariq. Phone: +94 777 202 225
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