ANALYZE statement
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MariaDB starting with 10.0.0
The ANALYZE statement
command is a new feature in MariaDB 10.1.0.
Contents
Command description
ANALYZE statement
command will run the statement, but instead of statement's output it will produce EXPLAIN output, accompanied with statistics from statement's execution.
MariaDB> analyze select * from tbl1 where key1 between 10 and 200 and col1 like 'foo%'\G *************************** 1. row *************************** id: 1 select_type: SIMPLE table: tbl1 type: range possible_keys: key1 key: key1 key_len: 5 ref: NULL rows: 181 r_rows: 181 filtered: 100.00 r_filtered: 10.50 Extra: Using index condition; Using where 1 row in set (0.02 sec) **gooo**
Compared to EXPLAIN
, ANALYZE
produces two extra columns:
- r_rows is an observation-based counterpart of rows column. It shows how many rows were actually read from the table.
- r_filtered is an observation-based counterpart of filtered column. It shows which fraction of rows was left after applying the WHERE condition.
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