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maxscale restart due to memory increase

Due to an increase in memory, maxscale automatically restarted and the DB connection was lost. This was the first time this had happened in over a year. The version of my maxscale is 2.4.8. I don't know what the problem is. Can you tell me about a case where this might happen?

DB Log

2023-10-24 11:09:04 5210330 [Warning] Aborted connection 5210330 to db: 'unconnected' user: 'maxscale' host: '*.*.*.*' (Got an error reading communication packets)

Application Log

2023-10-24 11:09:43,066 WARN [org.jboss.jca.adapters.jdbc.local.LocalManagedConnectionFactory] (default task-1) IJ030027: Destroying connection that is not valid, due to the following exception: org.mariadb.jdbc.MariaDbConnection@369e5a07: java.sql.SQLNonTransientConnectionException: (conn=421684) unexpected end of stream, read 0 bytes from 4 (socket was closed by server)

Maxscale Log

2023-10-24 11:09:07 alert : (421546) Fatal: MaxScale 2.4.8 received fatal signal 6. Commit ID: 5984af468c7c9aa01830bd82527cbbde28c90a44 System name: Linux Release string: NAME="CentOS Linux" 2023-10-24 11:09:08 alert : (421546) MariaDB MaxScale /app/maxscale/logs/maxscale.log Tue Oct 24 11:09:09 2023 2023-10-24 11:09:09 notice : syslog logging is enabled. 2023-10-24 11:09:09 notice : maxlog logging is enabled. 2023-10-24 11:09:09 notice : Using up to 37.73GiB of memory for query classifier cache 2023-10-24 11:09:09 notice : Working directory: /app/maxscale/logs 2023-10-24 11:09:09 notice : The collection of SQLite memory allocation statistics turned off. 2023-10-24 11:09:09 notice : Threading mode of SQLite set to Multi-thread. 2023-10-24 11:09:09 notice : MariaDB MaxScale 2.4.8 started (Commit: 5984af468c7c9aa01830bd82527cbbde28c90a44) 2023-10-24 11:09:09 notice : MaxScale is running in process 11444 2023-10-24 11:09:09 notice : Configuration file: /etc/maxscale.cnf 2023-10-24 11:09:09 notice : Log directory: /app/maxscale/logs 2023-10-24 11:09:09 notice : Data directory: /var/lib/maxscale 2023-10-24 11:09:09 notice : Module directory: /usr/lib64/maxscale 2023-10-24 11:09:09 notice : Service cache: /var/cache/maxscale 2023-10-24 11:09:09 notice : Worker message queue size: 1.00MiB 2023-10-24 11:09:09 notice : No query classifier specified, using default 'qc_sqlite'. 2023-10-24 11:09:09 notice : Loaded module qc_sqlite: V1.0.0 from /usr/lib64/maxscale/libqc_sqlite.so 2023-10-24 11:09:09 notice : Query classification results are cached and reused. Memory used per thread: 965.81MiB 2023-10-24 11:09:09 notice : The systemd watchdog is Enabled. Internal timeout = 30s 2023-10-24 11:09:09 notice : Loading /etc/maxscale.cnf. 2023-10-24 11:09:09 notice : /etc/maxscale.cnf.d does not exist, not reading. 2023-10-24 11:09:09 notice : Loaded module maxscaled: V2.0.0 from /usr/lib64/maxscale/libmaxscaled.so 2023-10-24 11:09:09 warning: [cli] THE 'cli' MODULE AND 'maxadmin' ARE DEPRECATED: Use 'maxctrl' instead 2023-10-24 11:09:09 notice : Loaded module cli: V1.0.0 from /usr/lib64/maxscale/libcli.so 2023-10-24 11:09:09 notice : Loaded module MariaDBClient: V1.1.0 from /usr/lib64/maxscale/libmariadbclient.so 2023-10-24 11:09:09 notice : [galeramon] Initialise the MySQL Galera Monitor module. 2023-10-24 11:09:09 notice : Loaded module galeramon: V2.0.0 from /usr/lib64/maxscale/libgaleramon.so 2023-10-24 11:09:09 notice : [readwritesplit] Initializing statement-based read/write split router module. 2023-10-24 11:09:09 notice : Loaded module readwritesplit: V1.1.0 from /usr/lib64/maxscale/libreadwritesplit.so 2023-10-24 11:09:09 notice : Loaded module MariaDBBackend: V2.0.0 from /usr/lib64/maxscale/libmariadbbackend.so 2023-10-24 11:09:09 notice : Loaded module mariadbbackendauth: V1.0.0 from /usr/lib64/maxscale/libmariadbbackendauth.so 2023-10-24 11:09:09 notice : Loaded module MaxAdminAuth: V2.1.0 from /usr/lib64/maxscale/libmaxadminauth.so 2023-10-24 11:09:09 notice : Loaded module mariadbauth: V1.1.0 from /usr/lib64/maxscale/libmariadbauth.so 2023-10-24 11:09:09 notice : Started REST API on [127.0.0.1]:8989 2023-10-24 11:09:09 notice : MaxScale started with 40 worker threads, each with a stack size of 8388608 bytes. 2023-10-24 11:09:09 notice : Starting a total of 2 services... 2023-10-24 11:09:09 notice : Server 'db01' charset: utf8 2023-10-24 11:09:09 notice : Server 'db01' version: 10.4.16-MariaDB-log 2023-10-24 11:09:09 warning: [MariaDBAuth] [Splitter-Service] User 'maxscale' is missing the SHOW DATABASES privilege. This means that MaxScale cannot see all databases and authentication can fail. 2023-10-24 11:09:09 notice : Server 'db02' charset: utf8 2023-10-24 11:09:09 notice : Server 'db02' version: 10.4.16-MariaDB-log 2023-10-24 11:09:09 warning: [MariaDBAuth] [Splitter-Service] User 'maxscale' is missing the SHOW DATABASES privilege. This means that MaxScale cannot see all databases and authentication can fail. 2023-10-24 11:09:09 notice : [MariaDBAuth] [Splitter-Service] Loaded 267 MySQL users for listener 'Splitter-Listener' from server 'db01' with checksum 0x3835117b. 2023-10-24 11:09:09 notice : Listening for connections at [0.0.0.0]:3306 2023-10-24 11:09:09 notice : Service 'Splitter-Service' started (1/2) 2023-10-24 11:09:09 notice : Listening for connections at [/var/run/maxscale/maxadmin.sock]:0 2023-10-24 11:09:09 notice : Service 'MaxAdmin-Service' started (2/2) 2023-10-24 11:09:09 notice : Journal file was created 690849 seconds ago. Maximum journal age is 28800 seconds. 2023-10-24 11:09:09 notice : Removing stale journal file for monitor 'Galera-Monitor'. 2023-10-24 11:09:09 notice : Server changed state: db01[**.db01:4306]: new_master. [Running] -> [Master, Synced, Running] 2023-10-24 11:09:09 notice : Server changed state: db02[**.db02:4306]: new_slave. [Running] -> [Slave, Synced, Running] 2023-10-24 11:09:43 alert : (49) Fatal: MaxScale 2.4.8 received fatal signal 6. Commit ID: 5984af468c7c9aa01830bd82527cbbde28c90a44 System name: Linux Release string: NAME="CentOS Linux"

Answer Answered by Markus Mäkelä in this comment.

MaxScale 2.4.8 is a relatively old release and the 2.4 series of MaxScale releases has reached EOL. I'd recommend upgrading to a version of MaxScale that is still maintained.

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