I upgrade some month ago from Ubuntu 18.04 to 20.04. So MySQL upgrade from 5.7.33 to 8.0.23.
I notice after the upgrade that MySQL is slow to start.
2021-02-24T09:20:16.972632Z 0 [System] [MY-013172] [Server] Received SHUTDOWN from user <via user signal>. Shutting down mysqld (Version: 8.0.23-0ubuntu0.20.04.1). 2021-02-24T09:23:19.459483Z 0 [System] [MY-010910] [Server] /usr/sbin/mysqld: Shutdown complete (mysqld 8.0.23-0ubuntu0.20.04.1) (Ubuntu). 2021-02-24T09:28:43.738171Z 0 [System] [MY-010116] [Server] /usr/sbin/mysqld (mysqld 8.0.23-0ubuntu0.20.04.1) starting as process 999 2021-02-24T09:28:44.973719Z 1 [System] [MY-013576] [InnoDB] InnoDB initialization has started. 2021-02-24T09:33:02.352311Z 1 [System] [MY-013577] [InnoDB] InnoDB initialization has ended. 2021-02-24T09:33:06.424798Z 0 [System] [MY-011323] [Server] X Plugin ready for connections. Bind-address: '::' port: 33060, socket: /var/run/mysqld/mysqlx.sock 2021-02-24T09:33:07.646778Z 0 [Warning] [MY-010068] [Server] CA certificate ca.pem is self signed. 2021-02-24T09:33:07.647106Z 0 [System] [MY-013602] [Server] Channel mysql_main configured to support TLS. Encrypted connections are now supported for this channel. 2021-02-24T09:33:08.295842Z 0 [System] [MY-010931] [Server] /usr/sbin/mysqld: ready for connections. Version: '8.0.23-0ubuntu0.20.04.1' socket: '/var/run/mysqld/mysqld.sock' port: 3306 (Ubuntu) The slowdown seems to come from the "InnoDB initialization".
The MySQL contains 70 databases (Wordpress) for development project and are not actively used.
I also notice this slowdown on 3 other servers. (but not as much and they contains less databases.)
Due to this slowdown, websites display "database connection" error during Innodb initialization.
What causes exactly this slowdown ? Is there any parameter to speed up the process ?
Edit : Actual configuration
# # The MySQL database server configuration file. # # One can use all long options that the program supports. # Run program with --help to get a list of available options and with # --print-defaults to see which it would actually understand and use. # # For explanations see # http://dev.mysql.com/doc/mysql/en/server-system-variables.html # Here is entries for some specific programs # The following values assume you have at least 32M ram [mysqld] # # * Basic Settings # user = mysql pid-file = /var/run/mysqld/mysqld.pid socket = /var/run/mysqld/mysqld.sock port = 3306 basedir = /usr datadir = /var/lib/mysql # If MySQL is running as a replication slave, this should be # changed. Ref https://dev.mysql.com/doc/refman/8.0/en/server-system-variables.html#sysvar_tmpdir tmpdir = /tmp # # Instead of skip-networking the default is now to listen only on # localhost which is more compatible and is not less secure. bind-address = 127.0.0.1 # # * Fine Tuning # key_buffer_size = 16M # max_allowed_packet = 64M # thread_stack = 256K # thread_cache_size = -1 # This replaces the startup script and checks MyISAM tables if needed # the first time they are touched myisam-recover-options = BACKUP # max_connections = 151 # table_open_cache = 4000 # # * Logging and Replication # # Both location gets rotated by the cronjob. # # Log all queries # Be aware that this log type is a performance killer. # general_log_file = /var/log/mysql/query.log # general_log = 1 # # Error log - should be very few entries. # log_error = /var/log/mysql/error.log # # Here you can see queries with especially long duration # slow_query_log = 1 # slow_query_log_file = /var/log/mysql/mysql-slow.log # long_query_time = 2 # log-queries-not-using-indexes # # The following can be used as easy to replay backup logs or for replication. # note: if you are setting up a replication slave, see README.Debian about # other settings you may need to change. # server-id = 1 # log_bin = /var/log/mysql/mysql-bin.log # binlog_expire_logs_seconds = 2592000 max_binlog_size = 100M # binlog_do_db = include_database_name # binlog_ignore_db = include_database_name skip-name-resolve table_open_cache = 4000 join_buffer_size = 8M tmp_table_size = 64M key_buffer_size = 48M max_heap_table_size = 64M innodb_buffer_pool_size = 1500M innodb_buffer_pool_instances = 1 innodb_log_file_size = 190M 