MySQL 如何获取执行中的Queries信息？
适用于：MySQL服务器-版本5.6及更高版本
目的： 了解MySQL中执行了哪些查询，并获得它们的统计数据。
查询信息的主要来源是 performance_schema.events_statements_summary_by_digest 。此表根据规范化查询的前1024个字符以及执行这些查询的默认模式来聚集数据。它包括诸如查询执行了多少次、总/平均/最小/最大执行次数、是否使用了索引等信息。
events_statements_summary_by_digest 一行数据示例:
select * from performance_schema.events_statements_summary_by_digest limit 1G ;
*************************** 1. row ***************************
SCHEMA_NAME: NULL
DIGEST: NULL
DIGEST_TEXT: NULL
COUNT_STAR: 15874319033
SUM_TIMER_WAIT: 1187054378614800688
MIN_TIMER_WAIT: 7544000
AVG_TIMER_WAIT: 8209124000
MAX_TIMER_WAIT: 3613526422741000
SUM_LOCK_TIME: 1501434543795000000
SUM_ERRORS: 19634001
SUM_WARNINGS: 104128780
SUM_ROWS_AFFECTED: 7586098231
SUM_ROWS_SENT: 793508469051
SUM_ROWS_EXAMINED: 73964574771009
SUM_CREATED_TMP_DISK_TABLES: 29299
SUM_CREATED_TMP_TABLES: 1626394519
SUM_SELECT_FULL_JOIN: 391188771
SUM_SELECT_FULL_RANGE_JOIN: 1396714
SUM_SELECT_RANGE: 363623329
SUM_SELECT_RANGE_CHECK: 18
SUM_SELECT_SCAN: 2403956125
SUM_SORT_MERGE_PASSES: 4072044
SUM_SORT_RANGE: 0
SUM_SORT_ROWS: 205672901636
SUM_SORT_SCAN: 2416156953
SUM_NO_INDEX_USED: 2258897285
SUM_NO_GOOD_INDEX_USED: 24
FIRST_SEEN: 2021-11-23 00:45:19.866135
LAST_SEEN: 2023-09-15 22:18:11.186681
QUANTILE_95: 5011872336
QUANTILE_99: 125892541179
QUANTILE_999: 1513561248436
QUERY_SAMPLE_TEXT: select a.*
,b.REFUND_SIGN
from t_orc_ve_bu_sale_order_to_c a
QUERY_SAMPLE_SEEN: 2023-09-15 22:18:04.394621
QUERY_SAMPLE_TIMER_WAIT: 4336854074000
1 row in set (0.00 sec)
