EXPLAIN FORMAT=JSON
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MariaDB starting with 10.1.2
Starting from version 10.1.2, MariaDB supports the EXPLAIN FORMAT=JSON syntax.
Synopsis
EXPLAIN FORMAT=JSON is a variant of EXPLAIN command that produces output in JSON form. The output always has one row which has only one column titled "JSON". The content is a JSON representation of query plan, formatted for readability:
MariaDB [test]> EXPLAIN FORMAT=JSON SELECT * FROM t1 WHERE col1=1\G *************************** 1. row *************************** EXPLAIN: { "query_block": { "select_id": 1, "table": { "table_name": "t1", "access_type": "ALL", "rows": 1000, "filtered": 100, "attached_condition": "(t1.col1 = 1)" } } }
MariaDB's output for EXPLAIN FORMAT=JSON is different from MySQL's. There are multiple reasons for that
- MySQL's output has deficiencies (some are listed here: EXPLAIN FORMAT=JSON in MySQL)
- MariaDB has optimizations that MySQL does not have. Ergo, MariaDB generates query plans that MySQL does not generate.
Differences from MySQL
[not yet complete] EXPLAIN FORMAT=JSON differences from MySQL.
Output format
TODO: describe our output format.
See also
- ANALYZE FORMAT=JSON produces output like EXPLAIN FORMAT=JSON, but amended with the data from query execution.
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