Mysqld high CPU usage

Emilian

Hello!
High CPU from Mysqld.
I use woocommerce, flatsome theme, and a few plugins (RankMath, Akismet, Social Login, Nginx helper)
3k products and 12k sales in the database.
Server DO: 2cpu, 4GB RAM.

tail -n 20 /var/log/mysql/mariadb-slow.log

Thread_id: 50640 Schema: website_com_KMixjvmu QC_hit: No

Query_time: 10.082259 Lock_time: 0.000139 Rows_sent: 5 Rows_examined: 184471
Rows_affected: 0 Bytes_sent: 161
Tmp_tables: 3 Tmp_disk_tables: 0 Tmp_table_sizes: 8372264
Full_scan: No Full_join: No Tmp_table: Yes Tmp_table_on_disk: No
Filesort: Yes Filesort_on_disk: No Merge_passes: 0 Priority_queue: Yes
SET timestamp=1603958986;
SELECT wp_posts.ID FROM wp_posts INNER JOIN wp_postmeta ON ( wp_posts.ID = wp_postmeta.post_id ) >INNER JOIN wp_postmeta AS mt1 ON ( wp_posts.ID = mt1.post_id ) WHERE 1=1 AND wp_posts.post_parent = 0 >AND (
wp_posts.ID NOT IN (
SELECT object_id
FROM wp_term_relationships
WHERE term_taxonomy_id IN (7)
)
) AND (
wp_postmeta.meta_key = 'total_sales'
AND
(
( mt1.meta_key = '_price' AND CAST(mt1.meta_value AS DECIMAL) > '0' )
)
) AND wp_posts.post_type = 'product' AND ((wp_posts.post_status = 'publish')) GROUP BY wp_posts.ID ORDER BY >wp_postmeta.meta_value+0 DESC LIMIT 0, 5;

Mysqltuner

MySQLTuner 1.7.19 - Major Hayden major@mhtx.net
Bug reports, feature requests, and downloads at http://mysqltuner.pl/
Run with '--help' for additional options and output filtering

[--] Skipped version check for MySQLTuner script

[OK] Logged in using credentials from Debian maintenance account.
[OK] Currently running supported MySQL version 10.3.25-MariaDB-1:10.3.25+maria_focal-log
[OK] Operating on 64-bit architecture

-------- Log file Recommendations ------------------------------------------------------------------
[!!] Log file doesn't exist

-------- Storage Engine Statistics -----------------------------------------------------------------
[--] Status: +Aria +CSV +InnoDB +MEMORY +MRG_MyISAM +MyISAM +PERFORMANCE_SCHEMA +SEQUENCE
[--] Data in InnoDB tables: 2.0M (Tables: 8)
[--] Data in MyISAM tables: 284.6M (Tables: 76)
[OK] Total fragmented tables: 0

-------- Analysis Performance Metrics --------------------------------------------------------------
[--] innodb_stats_on_metadata: OFF
[OK] No stat updates during querying INFORMATION_SCHEMA.

-------- Security Recommendations ------------------------------------------------------------------
[OK] There are no anonymous accounts for any database users
[!!] User 'netdata@127.0.0.1' has no password set.
[!!] There is no basic password file list!

-------- CVE Security Recommendations --------------------------------------------------------------
[--] Skipped due to --cvefile option undefined

-------- Performance Metrics -----------------------------------------------------------------------
[--] Up for: 1d 17h 54m 2s (11M q [76.316 qps], 52K conn, TX: 50G, RX: 3G)
[--] Reads / Writes: 97% / 3%
[--] Binary logging is disabled
[--] Physical Memory : 3.8G
[--] Max MySQL memory : 9.6G
[--] Other process memory: 0B
[--] Total buffers: 2.7G global + 71.5M per thread (100 max threads)
[--] P_S Max memory usage: 0B
[--] Galera GCache Max memory usage: 0B
[!!] Maximum reached memory usage: 5.2G (136.52% of installed RAM)
[!!] Maximum possible memory usage: 9.6G (251.01% of installed RAM)
[!!] Overall possible memory usage with other process exceeded memory
[OK] Slow queries: 0% (153/11M)
[OK] Highest usage of available connections: 37% (37/100)
[OK] Aborted connections: 0.04% (19/52808)
[!!] name resolution is active : a reverse name resolution is made for each new connection and can reduce >performance
[OK] Query cache is disabled by default due to mutex contention on multiprocessor machines.
[OK] Sorts requiring temporary tables: 0% (0 temp sorts / 4M sorts)
[OK] No joins without indexes
[!!] Temporary tables created on disk: 71% (1M on disk / 2M total)
[OK] Thread cache hit rate: 99% (61 created / 52K connections)
[OK] Table cache hit rate: 98% (432 open / 438 opened)
[OK] table_definition_cache(400) is upper than number of tables(243)
[OK] Open file limit used: 0% (471/500K)
[OK] Table locks acquired immediately: 99% (15M immediate / 15M locks)

-------- Performance schema ------------------------------------------------------------------------
[--] Performance schema is disabled.
[--] Memory used by P_S: 0B
[--] Sys schema isn't installed.

-------- ThreadPool Metrics ------------------------------------------------------------------------
[--] ThreadPool stat is enabled.
[--] Thread Pool Size: 2 thread(s).
[--] Using default value is good enough for your version (10.3.25-MariaDB-1:10.3.25+maria_focal-log)

-------- MyISAM Metrics ----------------------------------------------------------------------------
[!!] Key buffer used: 29.6% (39M used / 134M cache)
[OK] Key buffer size / total MyISAM indexes: 128.0M/69.7M
[OK] Read Key buffer hit rate: 100.0% (2B cached / 14K reads)
[!!] Write Key buffer hit rate: 85.2% (385K cached / 328K writes)

-------- InnoDB Metrics ----------------------------------------------------------------------------
[--] InnoDB is enabled.
[--] InnoDB Thread Concurrency: 0
[OK] InnoDB File per table is activated
[OK] InnoDB buffer pool / data size: 2.0G/2.0M
[!!] Ratio InnoDB log file size / InnoDB Buffer pool size (14.35546875 %): 147.0M * 2/2.0G should be equal to 25%
[!!] InnoDB buffer pool instances: 8
[--] Number of InnoDB Buffer Pool Chunk : 16 for 8 Buffer Pool Instance(s)
[OK] Innodb_buffer_pool_size aligned with Innodb_buffer_pool_chunk_size & Innodb_buffer_pool_instances
[OK] InnoDB Read buffer efficiency: 99.97% (1325690 hits/ 1326121 total)
[!!] InnoDB Write Log efficiency: 37.14% (325 hits/ 875 total)
[OK] InnoDB log waits: 0.00% (0 waits / 1200 writes)

-------- AriaDB Metrics ----------------------------------------------------------------------------
[--] AriaDB is enabled.
[OK] Aria pagecache size / total Aria indexes: 128.0M/1B
[OK] Aria pagecache hit rate: 98.5% (83M cached / 1M reads)

-------- TokuDB Metrics ----------------------------------------------------------------------------
[--] TokuDB is disabled.

-------- XtraDB Metrics ----------------------------------------------------------------------------
[--] XtraDB is disabled.

-------- Galera Metrics ----------------------------------------------------------------------------
[--] Galera is disabled.

-------- Replication Metrics -----------------------------------------------------------------------
[--] Galera Synchronous replication: NO
[--] No replication slave(s) for this server.
[--] Binlog format: ROW
[--] XA support enabled: ON
[--] Semi synchronous replication Master: OFF
[--] Semi synchronous replication Slave: OFF
[--] This is a standalone server

-------- Recommendations ---------------------------------------------------------------------------
General recommendations:
Set up a Secure Password for netdata@127.0.0.1 user: SET PASSWORD FOR 'netdata'@'SpecificDNSorIp' = >PASSWORD('secure_password');
Reduce your overall MySQL memory footprint for system stability
Dedicate this server to your database for highest performance.
>Configure your accounts with ip or subnets only, then update your configuration with skip-name-resolve=1
>When making adjustments, make tmp_table_size/max_heap_table_size equal
>Reduce your SELECT DISTINCT queries which have no LIMIT clause
>Performance schema should be activated for better diagnostics
>Consider installing Sys schema from https://github.com/mysql/mysql-sys for MySQL
>Consider installing Sys schema from https://github.com/FromDual/mariadb-sys for MariaDB
>Before changing innodb_log_file_size and/or innodb_log_files_in_group read this: https://bit.ly/2TcGgtU
Variables to adjust:
*** MySQL's maximum memory usage is dangerously high ***
*** Add RAM before increasing MySQL buffer variables ***
>tmp_table_size (> 128M)
max_heap_table_size (> 128M)
performance_schema = ON enable PFS
>innodb_log_file_size should be (=256M) if possible, so InnoDB total log files size equals to 25% of buffer pool size.
innodb_buffer_pool_instances(=2)

corus9

yeah it seems , after update im also experiencing high mysqld

tyrro

If you use WooCommerce I'd suggest switching your tables from MyISAM to InnoDB. Here's a good article about it: https://rtcamp.com/tutorials/mysql/myisam-to-innodb/

And you will need to optimized your MySQL config file, your current MySQL usage takes more memory then you have. Start by reducing amount of connections from 100 to just say 50, you can always increase it later if required.