What is the MySQL equivalent of PostgreSQL's EXPLAIN ANALYZE

Question

I\'d like to get a detailed query plan in MySQL similar to EXPLAIN ANALYZE shows in PostgreSQL. Is there an equivalent?

Answer 1

EDIT: While not a direct equivalent or as detailed as Explain Analyze here are some tools that you can look at

mysql offers EXPLAIN and procedure analyse()
http://dev.mysql.com/doc/refman/5.0/en/explain.html
http://dev.mysql.com/doc/refman/5.0/en/procedure-analyse.html

Answer 2

I have not used PostgreSQL before MySQL has EXPLAIN EXTENDED which gives more information than EXPLAIN and may give you the information you are looking for.

Answer 3

EXPLAIN EXTENDED

MariaDB/MySQL provide something called EXPLAIN EXTENDED. However there is no substitute for EXPLAIN ANALYZE. EXPLAIN EXTENDED provides no timing information whatsoever, and the internal break down is far less verbose.

Name: 'EXPLAIN'
Description:
Syntax:
EXPLAIN [explain_type] SELECT select_options

explain_type:
    EXTENDED
  | PARTITIONS

Or:

EXPLAIN tbl_name

The EXPLAIN statement can be used either as a way to obtain information
about how MySQL executes a statement, or as a synonym for DESCRIBE:

o When you precede a SELECT statement with the keyword EXPLAIN, MySQL
  displays information from the optimizer about the query execution
  plan. That is, MySQL explains how it would process the statement,
  including information about how tables are joined and in which order.
  EXPLAIN EXTENDED can be used to obtain additional information.

  For information about using EXPLAIN and EXPLAIN EXTENDED to obtain
  query execution plan information, see
  https://mariadb.com/kb/en/explain/.

o EXPLAIN PARTITIONS is useful only when examining queries involving
  partitioned tables. For details, see
  http://dev.mysql.com/doc/refman/5.5/en/partitioning-info.html.

o EXPLAIN tbl_name is synonymous with DESCRIBE tbl_name or SHOW COLUMNS
  FROM tbl_name. For information about DESCRIBE and SHOW COLUMNS, see
  [HELP DESCRIBE], and [HELP SHOW COLUMNS].

URL: https://mariadb.com/kb/en/explain/

For instance this is taken from this example,

EXPLAIN ANALYZE SELECT *
FROM history AS h1
WHERE EXISTS (
  SELECT 1
  FROM history AS h2
  WHERE h1.lead_id = h2.lead_id
  GROUP BY lead_id
  HAVING count(is_first OR NULL) > 1
);

Will produce something like this on PostgreSQL,

                                                     QUERY PLAN                                                     
--------------------------------------------------------------------------------------------------------------------
 Seq Scan on history h1  (cost=0.00..82680.50 rows=1100 width=9) (actual time=0.048..0.065 rows=3 loops=1)
   Filter: (SubPlan 1)
   Rows Removed by Filter: 3
   SubPlan 1
     ->  GroupAggregate  (cost=0.00..37.57 rows=1 width=5) (actual time=0.007..0.007 rows=0 loops=6)
           Group Key: h2.lead_id
           Filter: (count((h2.is_first OR NULL::boolean)) > 1)
           Rows Removed by Filter: 0
           ->  Seq Scan on history h2  (cost=0.00..37.50 rows=11 width=5) (actual time=0.003..0.004 rows=2 loops=6)
                 Filter: (h1.lead_id = lead_id)
                 Rows Removed by Filter: 4
 Planning time: 0.149 ms
 Execution time: 0.123 ms
(13 rows)

While this is the MySQL equivalent,

+------+--------------------+-------+------+---------------+------+---------+------+------+----------+-------------+
| id   | select_type        | table | type | possible_keys | key  | key_len | ref  | rows | filtered | Extra       |
+------+--------------------+-------+------+---------------+------+---------+------+------+----------+-------------+
|    1 | PRIMARY            | h1    | ALL  | NULL          | NULL | NULL    | NULL |    6 |   100.00 | Using where |
|    2 | DEPENDENT SUBQUERY | h2    | ALL  | NULL          | NULL | NULL    | NULL |    6 |   100.00 | Using where |
+------+--------------------+-------+------+---------------+------+---------+------+------+----------+-------------+
2 rows in set, 2 warnings (0.00 sec)

Answer 4

2020 Update EXPLAIN ANALYZE Available

Old question but just for an update, with version 8.0.18 Explain Analyze is also available in MySQL and you can use it like below:

mysql> explain analyze select count(*) from sbtest1 where k > 500000\G
*************************** 1. row ***************************
EXPLAIN: -> Aggregate: count(0) (actual time=178.225..178.225 rows=1 loops=1)
-> Filter: (sbtest1.k > 500000) (cost=98896.53 rows=493204) (actual time=0.022..147.502 rows=625262 loops=1)
-> Index range scan on sbtest1 using idx3 (cost=98896.53 rows=493204) (actual time=0.021..96.488 rows=625262 loops=1)

1 row in set (0.18 sec)

Answer 5

just for clarity, comment on accepted answer (don't have enough karma to add comment)

procedure analyse() is for a different purpose that EXPLAIN, it analyzes the data set of specified column and suggests the best data type, i.e. it's useful when we have 1000 rows of varchar(255) and want to check how much length do we really need, f.e. it might tell that varchar(23) would suffice

Answer 6

MySQL 8.0.18 introduces natively EXPLAIN ANALYZE:

MySQL 8.0.18 introduces EXPLAIN ANALYZE, which runs a query and produces EXPLAIN output along with timing and additional, iterator-based information about how the optimizer's expectations matched the actual execution. For each iterator, the following information is provided:

• Estimated execution cost

• Estimated number of returned rows

• Time to return first row

• Time to return all rows (actual cost)

• Number of rows returned by the iterator

• Number of loops

  EXPLAIN ANALYZE can be used only with SELECT statements.