MySQLTuner report

 >>  MySQLTuner 1.9.9
         * Jean-Marie Renouard <[email protected]>
         * Major Hayden <[email protected]>
 >>  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 passed on the command line
[OK] Currently running supported MySQL version 10.3.38-MariaDB-1:10.3.38+maria~deb10
[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: 19.8G (Tables: 289)
[!!] Total fragmented tables: 1

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

-------- Views Metrics -----------------------------------------------------------------------------

-------- Triggers Metrics --------------------------------------------------------------------------

-------- Routines Metrics --------------------------------------------------------------------------

-------- Security Recommendations ------------------------------------------------------------------
[OK] There are no anonymous accounts for any database users
[!!] User ''debian-sys-maint'@'localhost'' has no password set.
[!!] User 'XXXXXXXXX'@% does not specify hostname restrictions.
[!!] User 'XXXXXXXXX'@% does not specify hostname restrictions.
[!!] User 'XXXXXXXXX'@% does not specify hostname restrictions.
[!!] User 'XXXXXXXXX'@% does not specify hostname restrictions.
[!!] User 'XXXXXXXXX'@% does not specify hostname restrictions.
[!!] User 'XXXXXXXXX'@% does not specify hostname restrictions.
[!!] User 'XXXXXXXXX'@% does not specify hostname restrictions.
[!!] User 'XXXXXXXXX'@% does not specify hostname restrictions.
[!!] User 'XXXXXXXXX'@% does not specify hostname restrictions.
[--] There are 620 basic passwords in the list.

-------- CVE Security Recommendations --------------------------------------------------------------
[OK] NO SECURITY CVE FOUND FOR YOUR VERSION

-------- Performance Metrics -----------------------------------------------------------------------
[--] Up for: 1d 0h 10m 43s (42M q [482.713 qps], 234K conn, TX: 68G, RX: 48G)
[--] Reads / Writes: 52% / 48%
[--] Binary logging is disabled
[--] Physical Memory     : 31.4G
[--] Max MySQL memory    : 23.1G
[--] Other process memory: 0B
[--] Total buffers: 20.3G global + 18.9M per thread (151 max threads)
[--] P_S Max memory usage: 0B
[--] Galera GCache Max memory usage: 0B
[OK] Maximum reached memory usage: 21.6G (68.61% of installed RAM)
[OK] Maximum possible memory usage: 23.1G (73.43% of installed RAM)
[OK] Overall possible memory usage with other process is compatible with memory available
[OK] Slow queries: 0% (53K/42M)
[OK] Highest usage of available connections: 45% (69/151)
[OK] Aborted connections: 0.00%  (3/234933)
[!!] 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% (23 temp sorts / 111K sorts)
[!!] Joins performed without indexes: 13020
[OK] Temporary tables created on disk: 15% (204K on disk / 1M total)
[OK] Thread cache hit rate: 99% (100 created / 234K connections)
[OK] Table cache hit rate: 99% (55M hits / 55M requests)
[!!] table_definition_cache (400) is less than number of tables (450)
[OK] Open file limit used: 0% (60/16K)
[OK] Table locks acquired immediately: 100% (30K immediate / 30K locks)

-------- Performance schema ------------------------------------------------------------------------
[!!] Performance_schema should be activated.
[--] Sys schema isn't installed.

-------- ThreadPool Metrics ------------------------------------------------------------------------
[--] ThreadPool stat is disabled.

-------- MyISAM Metrics ----------------------------------------------------------------------------
[!!] Key buffer used: 18.2% (23.4M used / 128.0M cache)
[OK] Key buffer size / total MyISAM indexes: 128.0M/115.0K
[OK] Read Key buffer hit rate: 95.7% (94 cached / 4 reads)

-------- InnoDB Metrics ----------------------------------------------------------------------------
[--] InnoDB is enabled.
[--] InnoDB Thread Concurrency: 0
[OK] InnoDB File per table is activated
[OK] InnoDB buffer pool / data size: 20.0G/19.8G
[!!] Ratio InnoDB log file size / InnoDB Buffer pool size (0.46875%): 48.0M * 2/20.0G should be equal to 25%
[!!] InnoDB buffer pool instances: 8
[--] Number of InnoDB Buffer Pool Chunk: 160 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: 99.99% (16933855441 hits/ 16935163100 total)
[OK] InnoDB Write log efficiency: 99.88% (139408110 hits/ 139577954 total)
[OK] InnoDB log waits: 0.00% (0 waits / 169844 writes)

-------- Aria Metrics ------------------------------------------------------------------------------
[--] Aria Storage Engine is enabled.
[OK] Aria pagecache size / total Aria indexes: 128.0M/0B
[OK] Aria pagecache hit rate: 99.8% (31M cached / 64K 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:
    Run OPTIMIZE TABLE to defragment tables for better performance
      OPTIMIZE TABLE `XXXXXXXXX`.`XXXXXXXXX`; -- can free 968 MB
    Total freed space after theses OPTIMIZE TABLE : 968 Mb
    Set up a Secure Password for 'XXXXXXXXX'@'localhost' user: SET PASSWORD FOR 'XXXXXXXXX'@'localhost' = PASSWORD('secure_password');
    Restrict Host for 'XXXXXXXXX'@'%' to 'XXXXXXXXX'@LimitedIPRangeOrLocalhost
    RENAME USER 'XXXXXXXXX'@'%' TO 'XXXXXXXXX'@LimitedIPRangeOrLocalhost;
    Restrict Host for 'XXXXXXXXX'@'%' to 'XXXXXXXXX'@LimitedIPRangeOrLocalhost
    RENAME USER 'XXXXXXXXX'@'%' TO 'XXXXXXXXX'@LimitedIPRangeOrLocalhost;
    Restrict Host for 'XXXXXXXXX'@'%' to 'XXXXXXXXX'@LimitedIPRangeOrLocalhost
    RENAME USER 'XXXXXXXXX'@'%' TO 'XXXXXXXXX'@LimitedIPRangeOrLocalhost;
    Restrict Host for 'XXXXXXXXX'@'%' to 'XXXXXXXXX'@LimitedIPRangeOrLocalhost
    RENAME USER 'XXXXXXXXX'@'%' TO 'XXXXXXXXX'@LimitedIPRangeOrLocalhost;
    Restrict Host for 'XXXXXXXXX'@'%' to 'XXXXXXXXX'@LimitedIPRangeOrLocalhost
    RENAME USER 'XXXXXXXXX'@'%' TO 'XXXXXXXXX'@LimitedIPRangeOrLocalhost;
    Restrict Host for 'XXXXXXXXX'@'%' to 'XXXXXXXXX'@LimitedIPRangeOrLocalhost
    RENAME USER 'XXXXXXXXX'@'%' TO 'XXXXXXXXX'@LimitedIPRangeOrLocalhost;
    Restrict Host for 'XXXXXXXXX'@'%' to 'XXXXXXXXX'@LimitedIPRangeOrLocalhost
    RENAME USER 'XXXXXXXXX'@'%' TO 'XXXXXXXXX'@LimitedIPRangeOrLocalhost;
    Restrict Host for 'XXXXXXXXX'@'%' to 'XXXXXXXXX'@LimitedIPRangeOrLocalhost
    RENAME USER 'XXXXXXXXX'@'%' TO 'XXXXXXXXX'@LimitedIPRangeOrLocalhost;
    Restrict Host for 'XXXXXXXXX'@'%' to 'XXXXXXXXX'@LimitedIPRangeOrLocalhost
    RENAME USER 'XXXXXXXXX'@'%' TO 'XXXXXXXXX'@LimitedIPRangeOrLocalhost;
    Configure your accounts with ip or subnets only, then update your configuration with skip-name-resolve=1
    We will suggest raising the 'join_buffer_size' until JOINs not using indexes are found.
             See https://dev.mysql.com/doc/internals/en/join-buffer-size.html
             (specially the conclusions at the bottom of the page).
    Performance schema should be activated for better diagnostics
    Consider installing Sys schema from https://github.com/mysql/mysql-sys for MySQL
    Before changing innodb_log_file_size and/or innodb_log_files_in_group read this: https://bit.ly/2TcGgtU
Variables to adjust:
    skip-name-resolve=1
    join_buffer_size (> 256.0K, or always use indexes with JOINs)
    table_definition_cache(400) > 450 or -1 (autosizing if supported)
    performance_schema=ON
    key_buffer_size (~ 24M)
    innodb_log_file_size should be (=2G) if possible, so InnoDB total log files size equals 25% of buffer pool size.
    innodb_buffer_pool_instances(=20)