mysql – Optimizing MariaDB Performance

I need a different set of eyes checking my MariaDB settings. During peak load times, the CPU can hit upwards of 600% or more, and slows down WordPress application. I have used MySQLTuner to tweak a few settings.

Server is Debian 10.7, 32GB Ram, 8 Core cpu, Shared VM on Linode. It is running both Apache and MariaDB for a WordPress application.

I suspect it could be the large table that is being queried, it has over 6301558 rows and a size of 1.1GB.

mariadb.cnf file:

(mysqld)
symbolic-links=0
skip-external-locking
key_buffer_size = 128K
max_allowed_packet = 4M
query_cache_size = 0
query_cache_type = 0
tmp_table_size = 256M
max_heap_table_size = 256M
table_open_cache = 900
sort_buffer_size = 128K
read_buffer_size = 512K
read_rnd_buffer_size = 512K
net_buffer_length = 4K
thread_stack = 480K
innodb_file_per_table = 1
innodb_buffer_pool_size = 4G
innodb_buffer_pool_instances = 4
innodb_log_file_size = 512M
max_connections=300
max_user_connections=50
wait_timeout=50
interactive_timeout=50
long_query_time=5

Here is the MySQLTuner Summary:

-------- Storage Engine Statistics -----------------------------------------------------------------
(--) Status: +Aria +CSV +InnoDB +MEMORY +MRG_MyISAM +MyISAM +PERFORMANCE_SCHEMA +SEQUENCE 
(--) Data in InnoDB tables: 1.3G (Tables: 50)
(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
(OK) All database users have passwords assigned
(!!) There is no basic password file list!
 
-------- CVE Security Recommendations --------------------------------------------------------------
(--) Skipped due to --cvefile option undefined
 
-------- Performance Metrics -----------------------------------------------------------------------
(--) Up for: 2d 16h 34m 53s (34M q (146.936 qps), 60K conn, TX: 162G, RX: 6G)
(--) Reads / Writes: 98% / 2%
(--) Binary logging is disabled
(--) Physical Memory     : 31.4G
(--) Max MySQL memory    : 6.1G
(--) Other process memory: 0B
(--) Total buffers: 4.4G global + 5.8M per thread (300 max threads)
(--) P_S Max memory usage: 0B
(--) Galera GCache Max memory usage: 0B
(OK) Maximum reached memory usage: 4.6G (14.58% of installed RAM)
(OK) Maximum possible memory usage: 6.1G (19.43% of installed RAM)
(OK) Overall possible memory usage with other process is compatible with memory available
(OK) Slow queries: 0% (4K/34M)
(OK) Highest usage of available connections: 11% (33/300)
(!!) Aborted connections: 8.12%  (4923/60626)
(!!) 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% (352 temp sorts / 808K sorts)
(OK) No joins without indexes
(!!) Temporary tables created on disk: 46% (415K on disk / 892K total)
(OK) Thread cache hit rate: 99% (44 created / 60K connections)
(OK) Table cache hit rate: 94% (308 open / 325 opened)
(OK) table_definition_cache(400) is upper than number of tables(209)
(OK) Open file limit used: 0% (59/14K)
(OK) Table locks acquired immediately: 100% (52 immediate / 52 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: 8 thread(s).
(--) Using default value is good enough for your version (10.3.27-MariaDB-0+deb10u1)
 
-------- MyISAM Metrics ----------------------------------------------------------------------------
(!!) Key buffer used: 25.8% (33K used / 131K cache)
(OK) Key buffer size / total MyISAM indexes: 128.0K/124.0K
(!!) Read Key buffer hit rate: 90.0% (20 cached / 2 reads)
 
-------- InnoDB Metrics ----------------------------------------------------------------------------
(--) InnoDB is enabled.
(--) InnoDB Thread Concurrency: 0
(OK) InnoDB File per table is activated
(OK) InnoDB buffer pool / data size: 4.0G/1.3G
(OK) Ratio InnoDB log file size / InnoDB Buffer pool size: 512.0M * 2/4.0G should be equal to 25%
(OK) InnoDB buffer pool instances: 4
(--) Number of InnoDB Buffer Pool Chunk : 32 for 4 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: 100.00% (61483993760 hits/ 61484070155 total)
(OK) InnoDB Write log efficiency: 92.60% (3810440 hits/ 4114724 total)
(OK) InnoDB log waits: 0.00% (0 waits / 304284 writes)
 
-------- AriaDB Metrics ----------------------------------------------------------------------------
(--) AriaDB is enabled.
(OK) Aria pagecache size / total Aria indexes: 128.0M/1B
(OK) Aria pagecache hit rate: 98.8% (16M cached / 189K 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: MIXED
(--) XA support enabled: ON
(--) Semi synchronous replication Master: OFF
(--) Semi synchronous replication Slave: OFF
(--) This is a standalone server
 
-------- Recommendations ---------------------------------------------------------------------------
General recommendations:
    Control warning line(s) into /var/log/mysql/error.log file
    Reduce or eliminate unclosed connections and network issues
    Configure your accounts with ip or subnets only, then update your configuration with skip-name-resolve=1
    Temporary table size is already large - reduce result set size
    Reduce your SELECT DISTINCT queries without LIMIT clauses

Here is the Show InnoDB Status summary:

| InnoDB |      | 
=====================================
2021-02-22 04:27:30 0x7fab5b545700 INNODB MONITOR OUTPUT
=====================================
Per second averages calculated from the last 16 seconds
-----------------
BACKGROUND THREAD
-----------------
srv_master_thread loops: 43199 srv_active, 0 srv_shutdown, 186293 srv_idle
srv_master_thread log flush and writes: 229472
----------
SEMAPHORES
----------
OS WAIT ARRAY INFO: reservation count 4983384
OS WAIT ARRAY INFO: signal count 19744358
RW-shared spins 51316513, rounds 100262737, OS waits 897220
RW-excl spins 455471, rounds 5720299, OS waits 147869
RW-sx spins 2141, rounds 25812, OS waits 246
Spin rounds per wait: 1.95 RW-shared, 12.56 RW-excl, 12.06 RW-sx
------------
TRANSACTIONS
------------
Trx id counter 20743979
Purge done for trx's n:o < 20743956 undo n:o < 0 state: running
History list length 5
LIST OF TRANSACTIONS FOR EACH SESSION:
---TRANSACTION 421853553754616, not started
0 lock struct(s), heap size 1128, 0 row lock(s)
---TRANSACTION 421853553750400, not started
0 lock struct(s), heap size 1128, 0 row lock(s)
---TRANSACTION 421853553746184, ACTIVE 4 sec fetching rows
mysql tables in use 6, locked 0
0 lock struct(s), heap size 1128, 0 row lock(s)
MySQL thread id 58994, OS thread handle 140373653628672, query id 33162998 localhost wordpress Sending data
SELECT SQL_CALC_FOUND_ROWS DISTINCT `t1`.`id` FROM `gf_entry` AS `t1` LEFT JOIN `gf_entry_meta` AS `m2` ON (`m2`.`entry_id` = `t1`.`id` AND `m2`.`meta_key` = 228) LEFT JOIN `gf_entry_meta` AS `m3` ON (`m3`.`entry_id` = `t1`.`id` AND `m3`.`meta_key` = 68) LEFT JOIN `gf_entry_meta` AS `m4` ON (`m4`.`entry_id` = `t1`.`id` AND `m4`.`meta_key` = 71) LEFT JOIN `gf_entry_meta` AS `m5` ON (`m5`.`entry_id` = `t1`.`id` AND `m5`.`meta_key` = 42) LEFT JOIN `gf_entry_meta` AS `c6` ON (`c6`.`entry_id` = `t1`.`id` AND `c6`.`meta_key` = 'sequence') WHERE (`t1`.`form_id` IN 
Trx read view will not see trx with id >= 20743955, sees < 20743955
---TRANSACTION 421853553741968, not started
0 lock struct(s), heap size 1128, 0 row lock(s)
--------
FILE I/O
--------
I/O thread 0 state: waiting for completed aio requests (insert buffer thread)
I/O thread 1 state: waiting for completed aio requests (log thread)
I/O thread 2 state: waiting for completed aio requests (read thread)
I/O thread 3 state: waiting for completed aio requests (read thread)
I/O thread 4 state: waiting for completed aio requests (read thread)
I/O thread 5 state: waiting for completed aio requests (read thread)
I/O thread 6 state: waiting for completed aio requests (write thread)
I/O thread 7 state: waiting for completed aio requests (write thread)
I/O thread 8 state: waiting for completed aio requests (write thread)
I/O thread 9 state: waiting for completed aio requests (write thread)
Pending normal aio reads: (0, 0, 0, 0) , aio writes: (0, 0, 0, 0) ,
 ibuf aio reads:, log i/o's:, sync i/o's:
Pending flushes (fsync) log: 0; buffer pool: 0
78113 OS file reads, 2188616 OS file writes, 877265 OS fsyncs
0.00 reads/s, 0 avg bytes/read, 18.25 writes/s, 8.69 fsyncs/s
-------------------------------------
INSERT BUFFER AND ADAPTIVE HASH INDEX
-------------------------------------
Ibuf: size 1, free list len 17, seg size 19, 77 merges
merged operations:
 insert 95, delete mark 23, delete 0
discarded operations:
 insert 0, delete mark 0, delete 0
Hash table size 1106407, node heap has 2 buffer(s)
Hash table size 1106407, node heap has 9533 buffer(s)
Hash table size 1106407, node heap has 1 buffer(s)
Hash table size 1106407, node heap has 2 buffer(s)
Hash table size 1106407, node heap has 33 buffer(s)
Hash table size 1106407, node heap has 3 buffer(s)
Hash table size 1106407, node heap has 116 buffer(s)
Hash table size 1106407, node heap has 59 buffer(s)
581124.87 hash searches/s, 6749.39 non-hash searches/s
---
LOG
---
Log sequence number 77876397893
Log flushed up to   77876397893
Pages flushed up to 77876397893
Last checkpoint at  77876397846
0 pending log flushes, 0 pending chkp writes
335013 log i/o's done, 3.19 log i/o's/second
----------------------
BUFFER POOL AND MEMORY
----------------------
Total large memory allocated 4418699264
Dictionary memory allocated 154224
Buffer pool size   262144
Free buffers       170996
Database pages     81399
Old database pages 29966
Modified db pages  0
Percent of dirty pages(LRU & free pages): 0.000
Max dirty pages percent: 75.000
Pending reads 0
Pending writes: LRU 0, flush list 0, single page 0
Pages made young 284, not young 0
0.00 youngs/s, 0.00 non-youngs/s
Pages read 78047, created 3352, written 1647191
0.00 reads/s, 0.00 creates/s, 12.81 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: 81399, unzip_LRU len: 0
I/O sum(0):cur(0), unzip sum(0):cur(0)
----------------------
INDIVIDUAL BUFFER POOL INFO
----------------------
---BUFFER POOL 0
Buffer pool size   65536
Free buffers       42613
Database pages     20486
Old database pages 7542
Modified db pages  0
Percent of dirty pages(LRU & free pages): 0.000
Max dirty pages percent: 75.000
Pending reads 0
Pending writes: LRU 0, flush list 0, single page 0
Pages made young 56, not young 0
0.00 youngs/s, 0.00 non-youngs/s
Pages read 19547, created 939, written 502730
0.00 reads/s, 0.00 creates/s, 3.75 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: 20486, unzip_LRU len: 0
I/O sum(0):cur(0), unzip sum(0):cur(0)
---BUFFER POOL 1
Buffer pool size   65536
Free buffers       42824
Database pages     20336
Old database pages 7486
Modified db pages  0
Percent of dirty pages(LRU & free pages): 0.000
Max dirty pages percent: 75.000
Pending reads 0
Pending writes: LRU 0, flush list 0, single page 0
Pages made young 78, not young 0
0.00 youngs/s, 0.00 non-youngs/s
Pages read 19366, created 970, written 435222
0.00 reads/s, 0.00 creates/s, 5.37 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: 20336, unzip_LRU len: 0
I/O sum(0):cur(0), unzip sum(0):cur(0)
---BUFFER POOL 2
Buffer pool size   65536
Free buffers       42837
Database pages     20259
Old database pages 7458
Modified db pages  0
Percent of dirty pages(LRU & free pages): 0.000
Max dirty pages percent: 75.000
Pending reads 0
Pending writes: LRU 0, flush list 0, single page 0
Pages made young 101, not young 0
0.00 youngs/s, 0.00 non-youngs/s
Pages read 19576, created 683, written 288950
0.00 reads/s, 0.00 creates/s, 0.62 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: 20259, unzip_LRU len: 0
I/O sum(0):cur(0), unzip sum(0):cur(0)
---BUFFER POOL 3
Buffer pool size   65536
Free buffers       42722
Database pages     20318
Old database pages 7480
Modified db pages  0
Percent of dirty pages(LRU & free pages): 0.000
Max dirty pages percent: 75.000
Pending reads 0
Pending writes: LRU 0, flush list 0, single page 0
Pages made young 49, not young 0
0.00 youngs/s, 0.00 non-youngs/s
Pages read 19558, created 760, written 420289
0.00 reads/s, 0.00 creates/s, 3.06 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: 20318, 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
1 read views open inside InnoDB
Process ID=913, Main thread ID=140373985957632, state: sleeping
Number of rows inserted 324605, updated 93101, deleted 46031, read 45083162989
1.00 inserts/s, 0.75 updates/s, 0.12 deletes/s, 607231.05 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
============================