hi , Thank you everyone: A) Please report the exact version of MySQL used. : mysql> select version(); +------------+ | version() | +------------+ | 5.7.32-log | +------------+ 1 row in set (0.00 sec) mysql> \s -------------- ./mysql Ver 14.14 Distrib 5.7.32, for linux-glibc2.12 (x86_64) using EditLine wrapper Connection id: 26 Current database: Current user: root@localhost SSL: Not in use Current pager: less Using outfile: '' Using delimiter: ; Server version: 5.7.32-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: 45 sec Threads: 50 Questions: 3596 Slow queries: 6 Opens: 253 Flush tables: 1 Open tables: 246 Queries per second avg: 79.911 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 use sysbench : sysbench --db-driver=mysql /usr/share/sysbench/oltp_read_write.lua --mysql-host=127.0.0.1 --mysql-port=8307 --mysql-db=sbtest --mysql-user=root --mysql-password=coepaas --tables=16 --table_size=500000 --threads=16 --time=3600 --report-interval=1 prepare sysbench --db-driver=mysql /usr/share/sysbench/oltp_read_write.lua --mysql-host=127.0.0.1 --mysql-port=8307 --mysql-db=sbtest --mysql-user=root --mysql-password=coepaas --tables=16 --table_size=500000 --threads=64 --time=300 --report-interval=1 run B) Please report the full row returned by performance schema tables. In particular, seeing the data with both counts (COUNT columns) and sizes (SIZE columns) would help to understand if the issue is about missing an event entirely, or only about incorrect sizes. : mysql> desc memory_summary_by_user_by_event_name; +------------------------------+---------------------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +------------------------------+---------------------+------+-----+---------+-------+ | USER | char(32) | YES | | NULL | | | EVENT_NAME | varchar(128) | NO | | NULL | | | COUNT_ALLOC | bigint(20) unsigned | NO | | NULL | | | COUNT_FREE | bigint(20) unsigned | NO | | NULL | | | SUM_NUMBER_OF_BYTES_ALLOC | bigint(20) unsigned | NO | | NULL | | | SUM_NUMBER_OF_BYTES_FREE | bigint(20) unsigned | NO | | NULL | | | LOW_COUNT_USED | bigint(20) | NO | | NULL | | | CURRENT_COUNT_USED | bigint(20) | NO | | NULL | | | HIGH_COUNT_USED | bigint(20) | NO | | NULL | | | LOW_NUMBER_OF_BYTES_USED | bigint(20) | NO | | NULL | | | CURRENT_NUMBER_OF_BYTES_USED | bigint(20) | NO | | NULL | | | HIGH_NUMBER_OF_BYTES_USED | bigint(20) | NO | | NULL | | +------------------------------+---------------------+------+-----+---------+-------+ 12 rows in set (0.03 sec) mysql> select user,event_name,COUNT_ALLOC, COUNT_FREE, 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 group by user,event_name order by sum(SUM_NUMBER_OF_BYTES_ALLOC)/1024/1024 desc limit 30; +------+----------------------------------------------+-------------+------------+----------------+--------------------+-----------------+--------------------------+---------------------------+------------------------------------------+-----------------------------------------+---------------------------------------------+ | user | event_name | COUNT_ALLOC | COUNT_FREE | 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 | +------+----------------------------------------------+-------------+------------+----------------+--------------------+-----------------+--------------------------+---------------------------+------------------------------------------+-----------------------------------------+---------------------------------------------+ | root | memory/sql/Filesort_buffer::sort_keys | 605994 | 605994 | 0 | 0 | 66 | 0 | 16757496 | 83662.85746765 | 83662.85746765 | 0.00000000 | | root | memory/memory/HP_PTRS | 605188 | 605184 | 0 | 4 | 132 | 0 | 15168496 | 66379.10918427 | 66378.68377686 | 0.42540741 | | root | memory/mysys/IO_CACHE | 1819130 | 1819115 | 0 | 15 | 598 | 0 | 8676917 | 37891.48547363 | 37891.33700562 | 0.14846802 | | root | memory/sql/thd::main_mem_root | 215271 | 215067 | -137 | 204 | 1361 | -1117584 | 83515968 | 13687.92623901 | 13686.32955933 | 1.59667969 | | root | memory/innodb/mem0mem | 13435847 | 13429972 | -67 | 5875 | 15759 | -208760 | 125171685 | 9328.88556099 | 9317.41566944 | 11.46989155 | | root | memory/sql/QUICK_RANGE_SELECT::alloc | 2120215 | 2120215 | 0 | 0 | 89 | 0 | 361696 | 8217.38601685 | 8217.38601685 | 0.00000000 | | root | memory/sql/test_quick_select | 2096877 | 2096877 | 0 | 0 | 91 | 0 | 369824 | 8126.93417358 | 8126.93417358 | 0.00000000 | | root | memory/sql/String::value | 35833869 | 35828585 | -8 | 5284 | 8638 | -35576 | 26826664 | 1401.23159790 | 1380.67434692 | 20.55725098 | | root | memory/sql/Log_event | 5055446 | 5055446 | 0 | 0 | 292 | 0 | 77611 | 1074.57352924 | 1074.57352924 | 0.00000000 | | root | memory/innodb/fil0fil | 2462 | 2430 | 0 | 32 | 50 | 0 | 17050332 | 934.08673096 | 934.07672119 | 0.01000977 | | root | memory/sql/Prepared_statement::main_mem_root | 112358 | 112358 | 0 | 0 | 33024 | 0 | 270086112 | 876.96029663 | 876.96029663 | 0.00000000 | | root | memory/memory/HP_SHARE | 605146 | 605144 | 0 | 2 | 130 | 0 | 95321 | 422.73590088 | 422.73447323 | 0.00142765 | | root | memory/memory/HP_INFO | 302573 | 302572 | 0 | 1 | 65 | 0 | 93846 | 415.52423286 | 415.52262497 | 0.00160789 | | root | memory/memory/HP_KEYDEF | 302573 | 302573 | 0 | 0 | 65 | 0 | 61392 | 272.39651489 | 272.39651489 | 0.00000000 | | root | memory/sql/MYSQL_LOCK | 8393567 | 8393566 | 0 | 1 | 164 | 0 | 5512 | 256.29611206 | 256.29606628 | 0.00004578 | | root | memory/sql/Filesort_info::record_pointers | 304353 | 304353 | 0 | 0 | 68 | 0 | 52308 | 231.34230804 | 231.34230804 | 0.00000000 | | root | memory/sql/TABLE::sort_io_cache | 598972 | 598972 | 0 | 0 | 65 | 0 | 18200 | 159.94277954 | 159.94277954 | 0.00000000 | | root | memory/sql/Sort_param::tmp_buffer | 605090 | 605090 | 0 | 0 | 64 | 0 | 15872 | 140.80234528 | 140.80234528 | 0.00000000 | | root | memory/innodb/btr0sea | 412242 | 412242 | 0 | 0 | 178 | 0 | 121824 | 118.60642242 | 118.60642242 | 0.00000000 | | root | memory/innodb/std | 1642212 | 1523879 | -4478 | 118333 | 155326 | -2012408 | 7149160 | 88.44647217 | 84.83243561 | 3.61403656 | | root | memory/innodb/row_merge_sort | 16 | 16 | 0 | 0 | 16 | 0 | 50331648 | 48.00000000 | 48.00000000 | 0.00000000 | | root | memory/innodb/row0merge | 80 | 80 | 0 | 0 | 64 | 0 | 33557248 | 32.00366211 | 32.00366211 | 0.00000000 | | root | memory/innodb/btr0pcur | 910781 | 909120 | 0 | 1661 | 1661 | 0 | 263267 | 28.87248325 | 28.62141228 | 0.25107098 | | root | memory/innodb/btr0btr | 109747 | 109747 | 0 | 0 | 39 | 0 | 10707 | 24.33452797 | 24.33452797 | 0.00000000 | | root | memory/sql/Row_data_memory::memory | 2130 | 2130 | 0 | 0 | 6 | 0 | 55266 | 17.90101337 | 17.90101337 | 0.00000000 | | root | memory/sql/prune_partitions::exec | 3006 | 3006 | 0 | 0 | 24 | 0 | 97536 | 11.65045166 | 11.65045166 | 0.00000000 | | root | memory/sql/NET::buff | 216 | 215 | 0 | 1 | 216 | 0 | 11666920 | 11.12644196 | 11.11081028 | 0.01563168 | | NULL | memory/innodb/mem0mem | 6126 | 6122 | 0 | 4 | 17 | 0 | 34488 | 9.02374268 | 9.01861572 | 0.00512695 | | root | memory/sql/my_bitmap_map | 2120215 | 2120215 | 0 | 0 | 89 | 0 | 364 | 8.08877563 | 8.08877563 | 0.00000000 | | NULL | memory/innodb/std | 2238 | 2097 | 0 | 141 | 149 | 0 | 103848 | 6.80074310 | 6.79566193 | 0.00508118 | +------+----------------------------------------------+-------------+------------+----------------+--------------------+-----------------+--------------------------+---------------------------+------------------------------------------+-----------------------------------------+---------------------------------------------+ 30 rows in set (0.01 sec) ysql> desc memory_summary_global_by_event_name; +------------------------------+---------------------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +------------------------------+---------------------+------+-----+---------+-------+ | EVENT_NAME | varchar(128) | NO | | NULL | | | COUNT_ALLOC | bigint(20) unsigned | NO | | NULL | | | COUNT_FREE | bigint(20) unsigned | NO | | NULL | | | SUM_NUMBER_OF_BYTES_ALLOC | bigint(20) unsigned | NO | | NULL | | | SUM_NUMBER_OF_BYTES_FREE | bigint(20) unsigned | NO | | NULL | | | LOW_COUNT_USED | bigint(20) | NO | | NULL | | | CURRENT_COUNT_USED | bigint(20) | NO | | NULL | | | HIGH_COUNT_USED | bigint(20) | NO | | NULL | | | LOW_NUMBER_OF_BYTES_USED | bigint(20) | NO | | NULL | | | CURRENT_NUMBER_OF_BYTES_USED | bigint(20) | NO | | NULL | | | HIGH_NUMBER_OF_BYTES_USED | bigint(20) | NO | | NULL | | +------------------------------+---------------------+------+-----+---------+-------+ 11 rows in set (0.00 sec) ysql> select SUBSTRING_INDEX(event_name,'/',3) event_name, COUNT_ALLOC, COUNT_FREE, 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 group by SUBSTRING_INDEX(event_name,'/',3) order by sum(SUM_NUMBER_OF_BYTES_ALLOC)/1024/1024 desc limit 30 ; +----------------------------------------------------------+-------------+------------+----------------+--------------------+-----------------+--------------------------+---------------------------+------------------------------------------+-----------------------------------------+---------------------------------------------+ | event_name | COUNT_ALLOC | COUNT_FREE | 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 | +----------------------------------------------------------+-------------+------------+----------------+--------------------+-----------------+--------------------------+---------------------------+------------------------------------------+-----------------------------------------+---------------------------------------------+ | memory/sql/Filesort_buffer::sort_keys | 606028 | 606028 | 0 | 0 | 66 | 0 | 16757496 | 83662.89090729 | 83662.89090729 | 0.00000000 | | memory/memory/HP_PTRS | 605191 | 605188 | 0 | 3 | 132 | 0 | 15168496 | 66379.42242432 | 66379.10918427 | 0.31324005 | | memory/mysys/IO_CACHE | 1819234 | 1819219 | 0 | 15 | 598 | 0 | 8676917 | 37893.64198303 | 37893.49351501 | 0.14846802 | | memory/sql/thd::main_mem_root | 216196 | 216191 | -336 | 5 | 1167 | -2750976 | 81926784 | 13695.63818359 | 13695.59922791 | 0.03895569 | | memory/innodb/mem0mem | 13443029 | 13437150 | -67 | 5879 | 15776 | -208760 | 125206173 | 9340.26906013 | 9328.79404163 | 11.47501850 | | memory/sql/QUICK_RANGE_SELECT::alloc | 2120215 | 2120215 | 0 | 0 | 89 | 0 | 361696 | 8217.38601685 | 8217.38601685 | 0.00000000 | | memory/sql/test_quick_select | 2096912 | 2096912 | 0 | 0 | 91 | 0 | 369824 | 8127.06982422 | 8127.06982422 | 0.00000000 | | memory/sql/TABLE | 1216575 | 1214146 | 78 | 2429 | 3390 | -803304 | 2699059 | 2140.09445858 | 2137.98879147 | 2.10566711 | | memory/sql/String::value | 35917486 | 35917437 | -5375 | 49 | 3663 | -22065848 | 7422960 | 1406.24004364 | 1406.17586517 | 0.06417847 | | memory/sql/Log_event | 5055766 | 5055766 | 0 | 0 | 292 | 0 | 77611 | 1074.64448261 | 1074.64448261 | 0.00000000 | | memory/innodb/fil0fil | 12110 | 12078 | 0 | 32 | 55 | 0 | 17051212 | 934.76922035 | 934.75921059 | 0.01000977 | | memory/sql/Prepared_statement::main_mem_root | 112366 | 112366 | 0 | 0 | 33024 | 0 | 270086112 | 877.02264404 | 877.02264404 | 0.00000000 | | memory/memory/HP_SHARE | 605148 | 605146 | 0 | 2 | 130 | 0 | 95321 | 422.73729801 | 422.73590088 | 0.00139713 | | memory/memory/HP_INFO | 302574 | 302573 | 0 | 1 | 65 | 0 | 93846 | 415.52565765 | 415.52423286 | 0.00142479 | | memory/memory/HP_KEYDEF | 302574 | 302574 | 0 | 0 | 65 | 0 | 61392 | 272.39741516 | 272.39741516 | 0.00000000 | | memory/sql/MYSQL_LOCK | 8393953 | 8393952 | 0 | 1 | 165 | 0 | 5544 | 256.31195068 | 256.31190491 | 0.00004578 | | memory/sql/Filesort_info::record_pointers | 304421 | 304421 | 0 | 0 | 68 | 0 | 52308 | 231.36204147 | 231.36204147 | 0.00000000 | | memory/sql/TABLE::sort_io_cache | 599006 | 599006 | 0 | 0 | 65 | 0 | 18200 | 159.95185852 | 159.95185852 | 0.00000000 | | memory/sql/Sort_param::tmp_buffer | 605090 | 605090 | 0 | 0 | 64 | 0 | 15872 | 140.80234528 | 140.80234528 | 0.00000000 | | memory/innodb/btr0sea | 412254 | 412254 | 0 | 0 | 180 | 0 | 123632 | 118.61116028 | 118.61116028 | 0.00000000 | | memory/innodb/std | 1644519 | 1644424 | -122857 | 95 | 37449 | -5800536 | 3473224 | 95.25182343 | 95.24534607 | 0.00647736 | | memory/innodb/row_merge_sort | 16 | 16 | 0 | 0 | 16 | 0 | 50331648 | 48.00000000 | 48.00000000 | 0.00000000 | | memory/innodb/row0merge | 80 | 80 | 0 | 0 | 64 | 0 | 33557248 | 32.00366211 | 32.00366211 | 0.00000000 | | memory/performance_schema/prepared_statements_instances | 19 | 0 | 0 | 19 | 19 | 0 | 32374784 | 30.87500000 | 0.00000000 | 30.87500000 | | memory/innodb/btr0pcur | 910789 | 909126 | 0 | 1663 | 1663 | 0 | 263629 | 28.87325191 | 28.62183571 | 0.25141621 | | memory/innodb/btr0btr | 109750 | 109750 | 0 | 0 | 39 | 0 | 10707 | 24.33639622 | 24.33639622 | 0.00000000 | | memory/sql/Row_data_memory::memory | 2210 | 2210 | 0 | 0 | 6 | 0 | 55266 | 18.57595539 | 18.57595539 | 0.00000000 | | memory/performance_schema/events_statements_history_long | 1 | 0 | 0 | 1 | 1 | 0 | 14320000 | 13.65661621 | 0.00000000 | 13.65661621 | | memory/sql/prune_partitions::exec | 3006 | 3006 | 0 | 0 | 24 | 0 | 97536 | 11.65045166 | 11.65045166 | 0.00000000 | | memory/sql/NET::buff | 216 | 215 | 0 | 1 | 216 | 0 | 11666920 | 11.12644196 | 11.11081028 | 0.01563168 | +----------------------------------------------------------+-------------+------------+----------------+--------------------+-----------------+--------------------------+---------------------------+------------------------------------------+-----------------------------------------+---------------------------------------------+ 30 rows in set (0.01 sec) C) Please clarify if this issue is seen only on the "memory/sql/String::value" instrument, or if the same happens on other memory instruments. Likewise, this can help to understand if the issue is about some specific instrumentation, or more general. : event “memory/sql/String::value, memory/innodb/std” Looks problematic