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POMysql query optimisation - range searches
 

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  1. POMysql query optimisation - range searches
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    <p>Looking to find out some ideas on how to optimise this query - its pretty awkward with several range searches</p> <pre><code>SELECT t1.id, t1.custom_track_id, t1.deleted, t1.last_modified, t1.client_id FROM tracks t1 INNER JOIN tracks t2 ON t1.custom_track_id = t2.custom_track_id AND t1.last_modified &gt; t2.last_modified AND t1.deleted !=0 AND t2.deleted =0 AND t2.client_id IN ( 103, 115, 116 ) WHERE t1.client_id IN ( 103, 115, 116 ) </code></pre> <p>All the fields its looking to find and joining on are INT fields. </p> <p>Indexes (yes theres a few dodgy ones in there) : </p> <pre><code>+--------+------------+------------------------------------------------+--------------+----------------------------+-----------+-------------+----------+--------+------+------------+---------+---------------+ | Table | Non_unique | Key_name | Seq_in_index | Column_name | Collation | Cardinality | Sub_part | Packed | Null | Index_type | Comment | Index_comment | +--------+------------+------------------------------------------------+--------------+----------------------------+-----------+-------------+----------+--------+------+------------+---------+---------------+ | tracks | 0 | PRIMARY | 1 | id | A | 566045 | NULL | NULL | | BTREE | | | | tracks | 1 | client_id | 1 | client_id | A | 589 | NULL | NULL | | BTREE | | | | tracks | 1 | featured | 1 | featured | A | 16 | NULL | NULL | | BTREE | | | | tracks | 1 | system_status | 1 | system_status | A | 20 | NULL | NULL | | BTREE | | | | tracks | 1 | created_by | 1 | created_by | A | 225 | NULL | NULL | | BTREE | | | | tracks | 1 | custom_track_id | 1 | custom_track_id | A | 283022 | NULL | NULL | | BTREE | | | | tracks | 1 | custom_track_id | 2 | custom_artist_id | A | 283022 | NULL | NULL | | BTREE | | | | tracks | 1 | counterpoint_id | 1 | counterpoint_id | A | 113209 | NULL | NULL | YES | BTREE | | | | tracks | 1 | system_status_2 | 1 | system_status | A | 20 | NULL | NULL | | BTREE | | | | tracks | 1 | composition | 1 | composition | A | 13 | NULL | NULL | YES | BTREE | | | | tracks | 1 | published_start_date | 1 | published_start_date | A | 13 | NULL | NULL | YES | BTREE | | | | tracks | 1 | published_end_date | 1 | published_end_date | A | 13 | NULL | NULL | YES | BTREE | | | | tracks | 1 | deleted | 1 | deleted | A | 20 | NULL | NULL | | BTREE | | | | tracks | 1 | restricted_access_required | 1 | restricted_access_required | A | 13 | NULL | NULL | | BTREE | | | | tracks | 1 | mv_clientid_deleted_featured_restrictedaccess | 1 | client_id | A | 336 | NULL | NULL | | BTREE | | | | tracks | 1 | mv_clientid_deleted_featured_restrictedaccess | 2 | custom_track_id | A | 336 | NULL | NULL | | BTREE | | | | tracks | 1 | mv_clientid_deleted_featured_restrictedaccess | 3 | deleted | A | 336 | NULL | NULL | | BTREE | | | | tracks | 1 | mv_clientid_deleted_featured_restrictedaccess | 4 | last_modified | A | 336 | NULL | NULL | | BTREE | | | | tracks | 1 | mv_clientid_customtrackid_deleted_lastmodified | 1 | client_id | A | 336 | NULL | NULL | | BTREE | | | | tracks | 1 | mv_clientid_customtrackid_deleted_lastmodified | 2 | custom_track_id | A | 336 | NULL | NULL | | BTREE | | | | tracks | 1 | mv_clientid_customtrackid_deleted_lastmodified | 3 | deleted | A | 336 | NULL | NULL | | BTREE | | | | tracks | 1 | mv_clientid_customtrackid_deleted_lastmodified | 4 | last_modified | A | 336 | NULL | NULL | | BTREE | | | +--------+------------+------------------------------------------------+--------------+----------------------------+-----------+-------------+----------+--------+------+------------+---------+---------------+ </code></pre> <p>And the EXPLAIN : </p> <pre><code>---+---------+-------------------------------------------------+-------+--------------------------+ | id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra | +----+-------------+-------+-------+--------------------------------------------------------------------------------------------------------------------------------+-----------------------------------------------+---------+-------------------------------------------------+-------+--------------------------+ | 1 | SIMPLE | t1 | range | client_id,custom_track_id,deleted,mv_clientid_deleted_featured_restrictedaccess,mv_clientid_customtrackid_deleted_lastmodified | mv_clientid_deleted_featured_restrictedaccess | 4 | NULL | 16018 | Using where; Using index | | 1 | SIMPLE | t2 | ref | client_id,custom_track_id,deleted,mv_clientid_deleted_featured_restrictedaccess,mv_clientid_customtrackid_deleted_lastmodified | custom_track_id | 302 | synchtank_shared_application.t1.custom_track_id | 2 | Using where | +----+-------------+-------+-------+--------------------------------------------------------------------------------------------------------------------------------+-----------------------------------------------+---------+-------------------------------------------------+-------+--------------------------+ </code></pre> <p>So looking for ways to either optimise the query or the indexes. Im also curious why of the 2 composite indexes it could match on, it chooses the one without last_modified in it. </p> <p>EXPLAIN for Stephan : </p> <pre><code>+----+-------------+-------+-------+-----------------------------------------------+-----------------------------------------------+---------+------+-------+---------------------------------------------+ | id | select_type | table | type | possible_keys | key | key_len | ref | rows | Extra | +----+-------------+-------+-------+-----------------------------------------------+-----------------------------------------------+---------+------+-------+---------------------------------------------+ | 1 | SIMPLE | t1 | range | client_id | client_id | 4 | NULL | 8111 | Using where | | 1 | SIMPLE | t2 | range | mv_clientid_deleted_featured_restrictedaccess | mv_clientid_deleted_featured_restrictedaccess | 4 | NULL | 16018 | Using where; Using index; Using join buffer | +----+-------------+-------+-------+-----------------------------------------------+-----------------------------------------------+---------+------+-------+---------------------------------------------+ </code></pre>
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    1. PTQuestion
    1. USDoug McK
    1. USDoug McK
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    1. This table or related slice is empty.
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      1. PTAnswer
    1. This table or related slice is empty.
    1. COWhat values do the `deleted` fields contain?
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      1. POMysql query optimisation - range searches
      1. USGordon Linoff
    2. COeither 0 or a timestamp int
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      1. POMysql query optimisation - range searches
      1. USDoug McK
 

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