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-- GNU General Public License, version 2.0, for more details.
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-- Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA

DROP PROCEDURE IF EXISTS ps_trace_statement_digest;

DELIMITER $$

CREATE DEFINER='mysql.sys'@'localhost' PROCEDURE ps_trace_statement_digest (
        IN in_digest VARCHAR(32),
        IN in_runtime INT,
        IN in_interval DECIMAL(2,2),
        IN in_start_fresh BOOLEAN,
        IN in_auto_enable BOOLEAN
    )
    COMMENT '
Description
-----------

Traces all instrumentation within Performance Schema for a specific
Statement Digest.

When finding a statement of interest within the
performance_schema.events_statements_summary_by_digest table, feed
the DIGEST MD5 value in to this procedure, set how long to poll for,
and at what interval to poll, and it will generate a report of all
statistics tracked within Performance Schema for that digest for the
interval.

It will also attempt to generate an EXPLAIN for the longest running
example of the digest during the interval. Note this may fail, as:

   * Performance Schema truncates long SQL_TEXT values (and hence the
     EXPLAIN will fail due to parse errors)
   * the default schema is sys (so tables that are not fully qualified
     in the query may not be found)
   * some queries such as SHOW are not supported in EXPLAIN.

When the EXPLAIN fails, the error will be ignored and no EXPLAIN
output generated.

Requires the SUPER privilege for "SET sql_log_bin = 0;".

Parameters
-----------

in_digest (VARCHAR(32)):
  The statement digest identifier you would like to analyze
in_runtime (INT):
  The number of seconds to run analysis for
in_interval (DECIMAL(2,2)):
  The interval (in seconds, may be fractional) at which to try
  and take snapshots
in_start_fresh (BOOLEAN):
  Whether to TRUNCATE the events_statements_history_long and
  events_stages_history_long tables before starting
in_auto_enable (BOOLEAN):
  Whether to automatically turn on required consumers

Example
-----------

mysql> call ps_trace_statement_digest(\'891ec6860f98ba46d89dd20b0c03652c\', 10, 0.1, true, true);
+--------------------+
| SUMMARY STATISTICS |
+--------------------+
| SUMMARY STATISTICS |
+--------------------+
1 row in set (9.11 sec)

+------------+-----------+-----------+-----------+---------------+------------+------------+
| executions | exec_time | lock_time | rows_sent | rows_examined | tmp_tables | full_scans |
+------------+-----------+-----------+-----------+---------------+------------+------------+
|         21 | 4.11 ms   | 2.00 ms   |         0 |            21 |          0 |          0 |
+------------+-----------+-----------+-----------+---------------+------------+------------+
1 row in set (9.11 sec)

+------------------------------------------+-------+-----------+
| event_name                               | count | latency   |
+------------------------------------------+-------+-----------+
| stage/sql/checking query cache for query |    16 | 724.37 us |
| stage/sql/statistics                     |    16 | 546.92 us |
| stage/sql/freeing items                  |    18 | 520.11 us |
| stage/sql/init                           |    51 | 466.80 us |
...
| stage/sql/cleaning up                    |    18 | 11.92 us  |
| stage/sql/executing                      |    16 | 6.95 us   |
+------------------------------------------+-------+-----------+
17 rows in set (9.12 sec)

+---------------------------+
| LONGEST RUNNING STATEMENT |
+---------------------------+
| LONGEST RUNNING STATEMENT |
+---------------------------+
1 row in set (9.16 sec)

+-----------+-----------+-----------+-----------+---------------+------------+-----------+
| thread_id | exec_time | lock_time | rows_sent | rows_examined | tmp_tables | full_scan |
+-----------+-----------+-----------+-----------+---------------+------------+-----------+
|    166646 | 618.43 us | 1.00 ms   |         0 |             1 |          0 |         0 |
+-----------+-----------+-----------+-----------+---------------+------------+-----------+
1 row in set (9.16 sec)

// Truncated for clarity...
+-----------------------------------------------------------------+
| sql_text                                                        |
+-----------------------------------------------------------------+
| select hibeventhe0_.id as id1382_, hibeventhe0_.createdTime ... |
+-----------------------------------------------------------------+
1 row in set (9.17 sec)

+------------------------------------------+-----------+
| event_name                               | latency   |
+------------------------------------------+-----------+
| stage/sql/init                           | 8.61 us   |
| stage/sql/Waiting for query cache lock   | 453.23 us |
| stage/sql/init                           | 331.07 ns |
| stage/sql/checking query cache for query | 43.04 us  |
...
| stage/sql/freeing items                  | 30.46 us  |
| stage/sql/cleaning up                    | 662.13 ns |
+------------------------------------------+-----------+
18 rows in set (9.23 sec)

+----+-------------+--------------+-------+---------------+-----------+---------+-------------+------+-------+
| id | select_type | table        | type  | possible_keys | key       | key_len | ref         | rows | Extra |
+----+-------------+--------------+-------+---------------+-----------+---------+-------------+------+-------+
|  1 | SIMPLE      | hibeventhe0_ | const | fixedTime     | fixedTime | 775     | const,const |    1 | NULL  |
+----+-------------+--------------+-------+---------------+-----------+---------+-------------+------+-------+
1 row in set (9.27 sec)

Query OK, 0 rows affected (9.28 sec)
'
    SQL SECURITY INVOKER
    NOT DETERMINISTIC
    MODIFIES SQL DATA
BEGIN

    DECLARE v_start_fresh BOOLEAN DEFAULT false;
    DECLARE v_auto_enable BOOLEAN DEFAULT false;
    DECLARE v_explain     BOOLEAN DEFAULT true;
    DECLARE v_this_thread_enabed ENUM('YES', 'NO');
    DECLARE v_runtime INT DEFAULT 0;
    DECLARE v_start INT DEFAULT 0;
    DECLARE v_found_stmts INT;

    SET @log_bin := @@sql_log_bin;
    SET sql_log_bin = 0;

    -- Do not track the current thread, it will kill the stack
    SELECT INSTRUMENTED INTO v_this_thread_enabed FROM performance_schema.threads WHERE PROCESSLIST_ID = CONNECTION_ID();
    CALL sys.ps_setup_disable_thread(CONNECTION_ID());

    DROP TEMPORARY TABLE IF EXISTS stmt_trace;
    CREATE TEMPORARY TABLE stmt_trace (
        thread_id BIGINT UNSIGNED,
        timer_start BIGINT UNSIGNED,
        event_id BIGINT UNSIGNED,
        sql_text longtext,
        timer_wait BIGINT UNSIGNED,
        lock_time BIGINT UNSIGNED,
        errors BIGINT UNSIGNED,
        mysql_errno INT,
        rows_sent BIGINT UNSIGNED,
        rows_affected BIGINT UNSIGNED,
        rows_examined BIGINT UNSIGNED,
        created_tmp_tables BIGINT UNSIGNED,
        created_tmp_disk_tables BIGINT UNSIGNED,
        no_index_used BIGINT UNSIGNED,
        PRIMARY KEY (thread_id, timer_start)
    );

    DROP TEMPORARY TABLE IF EXISTS stmt_stages;
    CREATE TEMPORARY TABLE stmt_stages (
       event_id BIGINT UNSIGNED,
       stmt_id BIGINT UNSIGNED,
       event_name VARCHAR(128),
       timer_wait BIGINT UNSIGNED,
       PRIMARY KEY (event_id)
    );

    SET v_start_fresh = in_start_fresh;
    IF v_start_fresh THEN
        TRUNCATE TABLE performance_schema.events_statements_history_long;
        TRUNCATE TABLE performance_schema.events_stages_history_long;
    END IF;

    SET v_auto_enable = in_auto_enable;
    IF v_auto_enable THEN
        CALL sys.ps_setup_save(0);

        UPDATE performance_schema.threads
           SET INSTRUMENTED = IF(PROCESSLIST_ID IS NOT NULL, 'YES', 'NO');

        -- Only the events_statements_history_long and events_stages_history_long tables and their ancestors are needed
        UPDATE performance_schema.setup_consumers
           SET ENABLED = 'YES'
         WHERE NAME NOT LIKE '%\_history'
               AND NAME NOT LIKE 'events_wait%'
               AND NAME NOT LIKE 'events_transactions%'
               AND NAME <> 'statements_digest';

        UPDATE performance_schema.setup_instruments
           SET ENABLED = 'YES',
               TIMED   = 'YES'
         WHERE NAME LIKE 'statement/%' OR NAME LIKE 'stage/%';
    END IF;

    WHILE v_runtime < in_runtime DO
        SELECT UNIX_TIMESTAMP() INTO v_start;

        INSERT IGNORE INTO stmt_trace
        SELECT thread_id, timer_start, event_id, sql_text, timer_wait, lock_time, errors, mysql_errno, 
               rows_sent, rows_affected, rows_examined, created_tmp_tables, created_tmp_disk_tables, no_index_used
          FROM performance_schema.events_statements_history_long
        WHERE digest = in_digest;

        INSERT IGNORE INTO stmt_stages
        SELECT stages.event_id, stmt_trace.event_id,
               stages.event_name, stages.timer_wait
          FROM performance_schema.events_stages_history_long AS stages
          JOIN stmt_trace ON stages.nesting_event_id = stmt_trace.event_id;

        SELECT SLEEP(in_interval) INTO @sleep;
        SET v_runtime = v_runtime + (UNIX_TIMESTAMP() - v_start);
    END WHILE;

    SELECT "SUMMARY STATISTICS";

    SELECT COUNT(*) executions,
           sys.format_time(SUM(timer_wait)) AS exec_time,
           sys.format_time(SUM(lock_time)) AS lock_time,
           SUM(rows_sent) AS rows_sent,
           SUM(rows_affected) AS rows_affected,
           SUM(rows_examined) AS rows_examined,
           SUM(created_tmp_tables) AS tmp_tables,
           SUM(no_index_used) AS full_scans
      FROM stmt_trace;

    SELECT event_name,
           COUNT(*) as count,
           sys.format_time(SUM(timer_wait)) as latency
      FROM stmt_stages
     GROUP BY event_name
     ORDER BY SUM(timer_wait) DESC;

    SELECT "LONGEST RUNNING STATEMENT";

    SELECT thread_id,
           sys.format_time(timer_wait) AS exec_time,
           sys.format_time(lock_time) AS lock_time,
           rows_sent,
           rows_affected,
           rows_examined,
           created_tmp_tables AS tmp_tables,
           no_index_used AS full_scan
      FROM stmt_trace
     ORDER BY timer_wait DESC LIMIT 1;

    SELECT sql_text
      FROM stmt_trace
     ORDER BY timer_wait DESC LIMIT 1;

    SELECT sql_text, event_id INTO @sql, @sql_id
      FROM stmt_trace
    ORDER BY timer_wait DESC LIMIT 1;

    IF (@sql_id IS NOT NULL) THEN
        SELECT event_name,
               sys.format_time(timer_wait) as latency
          FROM stmt_stages
         WHERE stmt_id = @sql_id
         ORDER BY event_id;
    END IF;

    DROP TEMPORARY TABLE stmt_trace;
    DROP TEMPORARY TABLE stmt_stages;

    IF (@sql IS NOT NULL) THEN
        SET @stmt := CONCAT("EXPLAIN FORMAT=JSON ", @sql);
        BEGIN
            -- Not all queries support EXPLAIN, so catch the cases that are
            -- not supported. Currently that includes cases where the table
            -- is not fully qualified and is not in the default schema for this
            -- procedure as it's not possible to change the default schema inside
            -- a procedure.
            --
            -- Errno = 1064: You have an error in your SQL syntax
            -- Errno = 1146: Table '...' doesn't exist
            DECLARE CONTINUE HANDLER FOR 1064, 1146 SET v_explain = false;

            PREPARE explain_stmt FROM @stmt;
        END;

        IF (v_explain) THEN
            EXECUTE explain_stmt;
            DEALLOCATE PREPARE explain_stmt;
        END IF;
    END IF;

    IF v_auto_enable THEN
        CALL sys.ps_setup_reload_saved();
    END IF;
    -- Restore INSTRUMENTED for this thread
    IF (v_this_thread_enabed = 'YES') THEN
        CALL sys.ps_setup_enable_thread(CONNECTION_ID());
    END IF;

    SET sql_log_bin = @log_bin;
END$$

DELIMITER ;
