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I have an Amazon 24XL server

  • 96 Cores
  • 378 GB RAM
  • Database size 5.7G
  • Debian GNU/Linux 9 (stretch)
  • PHP 7.3.16
  • mysql Ver 15.1 Distrib 10.3.22-MariaDB

I have only one WordPress site where users read articles, there are 4-5 small plugins One plugins is used to add the points and rewards in my subscribers profile. When there are around 2500 Users on my site there are around 3000+ UPDATE queries that runs to update the table 'wp_custom_points_user'

The issue is that the queries stuck in updating I can't find the way to fix those things However server has much RAM , CPU available but due to queries on the same table it stuck and caused 502 on my site. I am looking to optimize MySQL to cater concurrent update queries as they are taking longer to respond and I suspect there are some locks. However I have all tables with indexing and using InnoDB

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Here is the SHOW ENGINE INNODB STATUS;

=====================================
2020-04-06 13:45:46 0x7f934bf24700 INNODB MONITOR OUTPUT
=====================================
Per second averages calculated from the last 27 seconds
-----------------
BACKGROUND THREAD
-----------------
srv_master_thread loops: 8196 srv_active, 0 srv_shutdown, 0 srv_idle
srv_master_thread log flush and writes: 8196
----------
SEMAPHORES
----------
OS WAIT ARRAY INFO: reservation count 15589494
OS WAIT ARRAY INFO: signal count 41500023
RW-shared spins 0, rounds 154525943, OS waits 1459106
RW-excl spins 0, rounds 10328037, OS waits 40587
RW-sx spins 71982, rounds 547220, OS waits 3916
Spin rounds per wait: 154525943.00 RW-shared, 10328037.00 RW-excl, 7.60 RW-sx
------------
TRANSACTIONS
------------
Trx id counter 351880322
Purge done for trx's n:o < 351880319 undo n:o < 0 state: running
History list length 1
... truncated...
mpact format; info bits 0
 0: len 4; hex 80000001; asc     ;;
 1: len 6; hex 000000000000; asc       ;;
 2: len 7; hex 80000000000000; asc        ;;
 3: len 4; hex 80004cd6; asc   L ;;
 4: len 4; hex 800186b0; asc     ;;

------------------
---TRANSACTION 351861705, ACTIVE 40 sec starting index read
mysql tables in use 1, locked 1
LOCK WAIT 2 lock struct(s), heap size 1136, 1 row lock(s)
MySQL thread id 421774, OS thread handle 140270896170752, query id 8187691 localhost wpdatabayf Updating
UPDATE `wp_custom_points_user` SET `total_points` = '18900' WHERE `user_id` = 188768
------- TRX HAS BEEN WAITING 40 SEC FOR THIS LOCK TO BE GRANTED:
RECORD LOCKS space id 1468 page no 5 n bits 568 index PRIMARY of table `wpdatabayf`.`wp_custom_points_user` trx id 351861705 lock_mode X waiting
Record lock, heap no 2 PHYSICAL RECORD: n_fields 5; compact format; info bits 0
 0: len 4; hex 80000001; asc     ;;
 1: len 6; hex 000000000000; asc       ;;
 2: len 7; hex 80000000000000; asc        ;;
 3: len 4; hex 80004cd6; asc   L ;;
 4: len 4; hex 800186b0; asc     ;;

---BUFFER POOL 1
.
.
.
.
---BUFFER POOL 31
Buffer pool size   8192
Free buffers       1725
Database pages     6096
Old database pages 2253
Modified db pages  183
Percent of dirty pages(LRU & free pages): 2.340
Max dirty pages percent: 75.000
Pending reads 0
Pending writes: LRU 0, flush list 0, single page 0
Pages made young 0, not young 0
0.00 youngs/s, 0.00 non-youngs/s
Pages read 5594, created 502, written 12349
0.00 reads/s, 0.00 creates/s, 0.74 writes/s
Buffer pool hit rate 1000 / 1000, young-making rate 0 / 1000 not 0 / 1000
Pages read ahead 0.00/s, evicted without access 0.00/s, Random read ahead 0.00/s
LRU len: 6096, unzip_LRU len: 0
I/O sum[0]:cur[0], unzip sum[0]:cur[0]
--------------
ROW OPERATIONS
--------------
0 queries inside InnoDB, 0 queries in queue
2 read views open inside InnoDB
Process ID=72108, Main thread ID=140323093444352, state: sleeping
Number of rows inserted 88380, updated 193228, deleted 34011, read 84305568368
11.44 inserts/s, 21.74 updates/s, 0.00 deletes/s, 12469107.55 reads/s
Number of system rows inserted 0, updated 0, deleted 0, read 0
0.00 inserts/s, 0.00 updates/s, 0.00 deletes/s, 0.00 reads/s
----------------------------
END OF INNODB MONITOR OUTPUT
============================
  • Are you asking for help fixing a MySQL problem or reducing the number of updates your plugin is making? – Rup Apr 6 at 13:56
  • @Rup thank you for your update I am looking to optimize mysql to cater concurrent update queries as they are taking longer to respond and I suspect there are some locks. However I have all tables with indexing and using InnoDB – naqi Apr 6 at 14:03
  • Please post TEXT results of A) SHOW CREATE TABLE wp_custom_points_user; for analysis. – Wilson Hauck May 17 at 15:39
  • Additional information request. Any SSD or NVME devices on MySQL Host server? Post on pastebin.com and share the links. From your SSH login root, Text results of: B) SHOW GLOBAL STATUS; after minimum 24 hours UPTIME C) SHOW GLOBAL VARIABLES; D) SHOW FULL PROCESSLIST; E) complete MySQLTuner report AND Optional very helpful information, if available includes - htop OR top for most active apps, ulimit -a for a Linux/Unix list of limits, iostat -xm 5 3 for IOPS by device and core/cpu count, for server workload tuning analysis to provide suggestions. – Wilson Hauck May 17 at 15:41
  • It would be helpful to explore the cause of this information in your SHOW ENGINE INNODB STATUS REPORT. Number of rows inserted 88380, updated 193228, deleted 34011, read 84305568368 11.44 inserts/s, 21.74 updates/s, 0.00 deletes/s, 12469107.55 reads/s - Reading 12 million rows per second average since startup can not be healthy. – Wilson Hauck Jun 8 at 18:50

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