hi , Thank you everyone: version: mysql> select version(); +------------+ | version() | +------------+ | 5.7.31-log | +------------+ 1 row in set (0.00 sec) mysql> \s -------------- ./mysql Ver 14.14 Distrib 5.7.31, for linux-glibc2.12 (x86_64) using EditLine wrapper Connection id: 36 Current database: performance_schema Current user: root@localhost SSL: Not in use Current pager: less Using outfile: '' Using delimiter: ; Server version: 5.7.31-log MySQL Community Server (GPL) Protocol version: 10 Connection: Localhost via UNIX socket Server characterset: utf8 Db characterset: utf8 Client characterset: utf8 Conn. characterset: utf8 UNIX socket: /tmp/mysql-5.7-8307.sock Uptime: 3 min 53 sec Threads: 12 Questions: 997215 Slow queries: 0 Opens: 1325 Flush tables: 1 Open tables: 957 Queries per second avg: 4279.892 OS : CentOS Linux release 7.8.2003 (Core) mysql> UPDATE performance_schema.setup_instruments SET ENABLED = 'YES' WHERE NAME LIKE 'memory/%'; Query OK, 307 rows affected (0.00 sec) Rows matched: 377 Changed: 307 Warnings: 0 I found events (But not necessarily all) that have such problems: memory/sql/String::value: mysql> select user,event_name,LOW_COUNT_USED, CURRENT_COUNT_USED, HIGH_COUNT_USED,LOW_NUMBER_OF_BYTES_USED,HIGH_NUMBER_OF_BYTES_USED, sum(SUM_NUMBER_OF_BYTES_ALLOC)/1024/1024, sum(SUM_NUMBER_OF_BYTES_FREE)/1024/1024, sum(CURRENT_NUMBER_OF_BYTES_USED)/1024/1024 from memory_summary_by_user_by_event_name where event_name like 'memory/sql/String::value' group by user,event_name order by sum(CURRENT_NUMBER_OF_BYTES_USED)/1024/1024 desc limit 10\G *************************** 1. row *************************** user: root event_name: memory/sql/String::value LOW_COUNT_USED: 0 CURRENT_COUNT_USED: 11390 HIGH_COUNT_USED: 11534 LOW_NUMBER_OF_BYTES_USED: 18224 HIGH_NUMBER_OF_BYTES_USED: 53321408 sum(SUM_NUMBER_OF_BYTES_ALLOC)/1024/1024: 354.41739655 sum(SUM_NUMBER_OF_BYTES_FREE)/1024/1024: 311.76085663 sum(CURRENT_NUMBER_OF_BYTES_USED)/1024/1024: 42.65653992 *************************** 2. row *************************** user: NULL event_name: memory/sql/String::value LOW_COUNT_USED: 0 CURRENT_COUNT_USED: 0 HIGH_COUNT_USED: 0 LOW_NUMBER_OF_BYTES_USED: 0 HIGH_NUMBER_OF_BYTES_USED: 0 sum(SUM_NUMBER_OF_BYTES_ALLOC)/1024/1024: 0.00000000 sum(SUM_NUMBER_OF_BYTES_FREE)/1024/1024: 0.00000000 sum(CURRENT_NUMBER_OF_BYTES_USED)/1024/1024: 0.00000000 2 rows in set (0.01 sec) mysql> select SUBSTRING_INDEX(event_name,'/',3) event_name,LOW_COUNT_USED, CURRENT_COUNT_USED, HIGH_COUNT_USED,LOW_NUMBER_OF_BYTES_USED,HIGH_NUMBER_OF_BYTES_USED, sum(SUM_NUMBER_OF_BYTES_ALLOC)/1024/1024, sum(SUM_NUMBER_OF_BYTES_FREE)/1024/1024, sum(CURRENT_NUMBER_OF_BYTES_USED)/1024/1024 from memory_summary_global_by_event_name where event_name like 'memory/sql/String::value' group by SUBSTRING_INDEX(event_name,'/',3) order by sum(CURRENT_NUMBER_OF_BYTES_USED)/1024/1024 desc limit 10 \G *************************** 1. row *************************** event_name: memory/sql/String::value LOW_COUNT_USED: -11358 CURRENT_COUNT_USED: 87 HIGH_COUNT_USED: 2742 LOW_NUMBER_OF_BYTES_USED: -44653552 HIGH_NUMBER_OF_BYTES_USED: 19213488 sum(SUM_NUMBER_OF_BYTES_ALLOC)/1024/1024: 356.04094696 sum(SUM_NUMBER_OF_BYTES_FREE)/1024/1024: 355.76100922 sum(CURRENT_NUMBER_OF_BYTES_USED)/1024/1024: 0.27993774 1 row in set (0.01 sec) memory/sql/THD::transactions::mem_root: mysql> select user,event_name,LOW_COUNT_USED, CURRENT_COUNT_USED, HIGH_COUNT_USED,LOW_NUMBER_OF_BYTES_USED,HIGH_NUMBER_OF_BYTES_USED, sum(SUM_NUMBER_OF_BYTES_ALLOC)/1024/1024, sum(SUM_NUMBER_OF_BYTES_FREE)/1024/1024, sum(CURRENT_NUMBER_OF_BYTES_USED)/1024/1024 from memory_summary_by_user_by_event_name where event_name like 'memory/sql/THD::transactions::mem_root' group by user,event_name order by sum(CURRENT_NUMBER_OF_BYTES_USED)/1024/1024 desc limit 10\G *************************** 1. row *************************** user: root event_name: memory/sql/THD::transactions::mem_root LOW_COUNT_USED: 0 CURRENT_COUNT_USED: 953 HIGH_COUNT_USED: 953 LOW_NUMBER_OF_BYTES_USED: 0 HIGH_NUMBER_OF_BYTES_USED: 3918736 sum(SUM_NUMBER_OF_BYTES_ALLOC)/1024/1024: 3.73719788 sum(SUM_NUMBER_OF_BYTES_FREE)/1024/1024: 0.00000000 sum(CURRENT_NUMBER_OF_BYTES_USED)/1024/1024: 3.73719788 *************************** 2. row *************************** user: NULL event_name: memory/sql/THD::transactions::mem_root LOW_COUNT_USED: 0 CURRENT_COUNT_USED: 0 HIGH_COUNT_USED: 0 LOW_NUMBER_OF_BYTES_USED: 0 HIGH_NUMBER_OF_BYTES_USED: 0 sum(SUM_NUMBER_OF_BYTES_ALLOC)/1024/1024: 0.00000000 sum(SUM_NUMBER_OF_BYTES_FREE)/1024/1024: 0.00000000 sum(CURRENT_NUMBER_OF_BYTES_USED)/1024/1024: 0.00000000 2 rows in set (0.01 sec) mysql> select SUBSTRING_INDEX(event_name,'/',3) event_name,LOW_COUNT_USED, CURRENT_COUNT_USED, HIGH_COUNT_USED,LOW_NUMBER_OF_BYTES_USED,HIGH_NUMBER_OF_BYTES_USED, sum(SUM_NUMBER_OF_BYTES_ALLOC)/1024/1024, sum(SUM_NUMBER_OF_BYTES_FREE)/1024/1024, sum(CURRENT_NUMBER_OF_BYTES_USED)/1024/1024 from memory_summary_global_by_event_name where event_name like 'memory/sql/THD::transactions::mem_root' group by SUBSTRING_INDEX(event_name,'/',3) order by sum(CURRENT_NUMBER_OF_BYTES_USED)/1024/1024 desc limit 10\G *************************** 1. row *************************** event_name: memory/sql/THD::transactions::mem_root LOW_COUNT_USED: -950 CURRENT_COUNT_USED: 3 HIGH_COUNT_USED: 498 LOW_NUMBER_OF_BYTES_USED: -3906400 HIGH_NUMBER_OF_BYTES_USED: 2047776 sum(SUM_NUMBER_OF_BYTES_ALLOC)/1024/1024: 3.73719788 sum(SUM_NUMBER_OF_BYTES_FREE)/1024/1024: 3.72543335 sum(CURRENT_NUMBER_OF_BYTES_USED)/1024/1024: 0.01176453 1 row in set (0.00 sec) memory/sql/thd::main_mem_root: mysql> select user,event_name,LOW_COUNT_USED, CURRENT_COUNT_USED, HIGH_COUNT_USED,LOW_NUMBER_OF_BYTES_USED,HIGH_NUMBER_OF_BYTES_USED, sum(SUM_NUMBER_OF_BYTES_ALLOC)/1024/1024, sum(SUM_NUMBER_OF_BYTES_FREE)/1024/1024, sum(CURRENT_NUMBER_OF_BYTES_USED)/1024/1024 from memory_summary_by_user_by_event_name where event_name like 'memory/sql/thd::main_mem_root' group by user,event_name order by sum(CURRENT_NUMBER_OF_BYTES_USED)/1024/1024 desc limit 10\G *************************** 1. row *************************** user: root event_name: memory/sql/thd::main_mem_root LOW_COUNT_USED: 0 CURRENT_COUNT_USED: 957 HIGH_COUNT_USED: 1569 LOW_NUMBER_OF_BYTES_USED: 0 HIGH_NUMBER_OF_BYTES_USED: 13460784 sum(SUM_NUMBER_OF_BYTES_ALLOC)/1024/1024: 12168.13130951 sum(SUM_NUMBER_OF_BYTES_FREE)/1024/1024: 12160.64032745 sum(CURRENT_NUMBER_OF_BYTES_USED)/1024/1024: 7.49098206 *************************** 2. row *************************** user: NULL event_name: memory/sql/thd::main_mem_root LOW_COUNT_USED: 0 CURRENT_COUNT_USED: 0 HIGH_COUNT_USED: 0 LOW_NUMBER_OF_BYTES_USED: 0 HIGH_NUMBER_OF_BYTES_USED: 0 sum(SUM_NUMBER_OF_BYTES_ALLOC)/1024/1024: 0.00000000 sum(SUM_NUMBER_OF_BYTES_FREE)/1024/1024: 0.00000000 sum(CURRENT_NUMBER_OF_BYTES_USED)/1024/1024: 0.00000000 2 rows in set (0.00 sec) mysql> select SUBSTRING_INDEX(event_name,'/',3) event_name,LOW_COUNT_USED, CURRENT_COUNT_USED, HIGH_COUNT_USED,LOW_NUMBER_OF_BYTES_USED,HIGH_NUMBER_OF_BYTES_USED, sum(SUM_NUMBER_OF_BYTES_ALLOC)/1024/1024, sum(SUM_NUMBER_OF_BYTES_FREE)/1024/1024, sum(CURRENT_NUMBER_OF_BYTES_USED)/1024/1024 from memory_summary_global_by_event_name where event_name like 'memory/sql/thd::main_mem_root' group by SUBSTRING_INDEX(event_name,'/',3) order by sum(CURRENT_NUMBER_OF_BYTES_USED)/1024/1024 desc limit 10 \G *************************** 1. row *************************** event_name: memory/sql/thd::main_mem_root LOW_COUNT_USED: -951 CURRENT_COUNT_USED: 6 HIGH_COUNT_USED: 1046 LOW_NUMBER_OF_BYTES_USED: -7805808 HIGH_NUMBER_OF_BYTES_USED: 9168000 sum(SUM_NUMBER_OF_BYTES_ALLOC)/1024/1024: 12169.65657806 sum(SUM_NUMBER_OF_BYTES_FREE)/1024/1024: 12169.60979462 sum(CURRENT_NUMBER_OF_BYTES_USED)/1024/1024: 0.04678345 1 row in set (0.01 sec)