MySQL 8.4 发行说明
跟踪特定语句摘要的所有性能架构检测。
如果您在性能架构 events_statements_summary_by_digest 表中找到感兴趣的语句，请将其 DIGEST 列的 MD5 值指定给此过程，并指明轮询持续时间和间隔。结果是该间隔内针对该摘要在性能架构中跟踪的所有统计信息的报告。
该过程还会尝试为该间隔内运行时间最长的摘要示例执行 EXPLAIN。此尝试可能会失败，因为性能架构会截断长的 SQL_TEXT 值。因此，由于解析错误，EXPLAIN 会失败。
此过程通过操作 sql_log_bin 系统变量的会话值来在其执行期间禁用二进制日志记录。这是一项受限操作，因此该过程需要足够的权限来设置受限会话变量。请参阅 第 7.1.9.1 节，“系统变量权限”。
in_digest VARCHAR(32)：要分析的语句摘要标识符。in_runtime INT：分析运行时间（以秒为单位）。in_interval DECIMAL(2,2)：尝试获取快照的分析间隔（可以是小数），以秒为单位。in_start_fresh BOOLEAN：是否在开始之前截断性能架构events_statements_history_long和events_stages_history_long表。in_auto_enable BOOLEAN：是否自动启用所需的使用者。
mysql> CALL sys.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/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/init | 331.07 ns |
...
| 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)