Server version: 10.11.6-MariaDB-1:10.11.6+maria~deb11
32 GB RAM, 4 CPU cores, Linux on x64, SSD storage

The memory limits from where? What is your mariadb configuration?

this is the output of mysqltuner. The max MySQL Memory of 4.8G is exceeded by 6-fold:

-------- Performance Metrics -----------------------------------------------------------------------
[--] Up for: 6m 56s (49K q [118.413 qps], 432 conn, TX: 13M, RX: 23M)
[--] Reads / Writes: 18% / 82%
[--] Binary logging is disabled
[--] Physical Memory : 31.2G
[--] Max MySQL memory : 4.8G
[--] Other process memory: 0B
[--] Total buffers: 1.5G global + 6.7M per thread (500 max threads)
[--] P_S Max memory usage: 72B
[--] Galera GCache Max memory usage: 0B
[OK] Maximum reached memory usage: 1.6G (5.07% of installed RAM)
[OK] Maximum possible memory usage: 4.8G (15.39% of installed RAM)
[OK] Overall possible memory usage with other process is compatible with memory available
[!!] Slow queries: 56% (27K/49K)
[OK] Highest usage of available connections: 1% (5/500)
[OK] Aborted connections: 0.00% (0/432)
[!!] name resolution is active : a reverse name resolution is made for each new connection and can reduce performance
[!!] Query cache may be disabled by default due to mutex contention.
[OK] Query cache efficiency: 23.5% (3K cached / 15K selects)
[OK] Query cache prunes per day: 0
[OK] Sorts requiring temporary tables: 0% (0 temp sorts / 466 sorts)
[!!] Joins performed without indexes: 31
[OK] Temporary tables created on disk: 7% (218 on disk / 2K total)
[OK] Thread cache hit rate: 98% (5 created / 432 connections)
[!!] Table cache hit rate: 6% (4K open / 60K opened)
[OK] Open file limit used: 0% (59/64K)
[OK] Table locks acquired immediately: 99% (29K immediate / 29K locks)

BUT: The real memory consumption according to htop and other system tools is 18 G of RAM (while mariadb itself thinks it is only using 1.6G)

SHOW GLOBAL STATUS tells:

htop however says:
22G (which is 10x more than STATUS claims)

This is a log of all crashes:

2024-02-05 09:00:46 MEM_CRIT: 31726092 - restart mariadb-server
2024-02-05 09:15:38 MEM_CRIT: 29104500 - restart mariadb-server
2024-02-05 09:31:02 CRASHED: start mariadb-server
2024-02-05 09:45:37 MEM_CRIT: 30282144 - restart mariadb-server
2024-02-05 10:00:36 MEM_CRIT: 28055600 - restart mariadb-server
2024-02-05 10:15:36 MEM_CRIT: 24246396 - restart mariadb-server
2024-02-05 10:30:36 MEM_CRIT: 24133768 - restart mariadb-server
2024-02-05 10:45:29 MEM_CRIT: 34178228 - restart mariadb-server
2024-02-05 11:00:30 MEM_CRIT: 22367804 - restart mariadb-server
2024-02-05 11:15:30 MEM_CRIT: 24386304 - restart mariadb-server
2024-02-05 11:30:29 MEM_CRIT: 24058304 - restart mariadb-server
2024-02-05 11:45:33 MEM_CRIT: 30246664 - restart mariadb-server
2024-02-05 12:00:31 MEM_CRIT: 29184444 - restart mariadb-server
2024-02-05 12:15:01 CRASHED: start mariadb-server
2024-02-05 12:30:34 MEM_CRIT: 32789068 - restart mariadb-server
2024-02-05 12:45:36 MEM_CRIT: 30915580 - restart mariadb-server
2024-02-05 13:00:34 MEM_CRIT: 31627160 - restart mariadb-server
2024-02-05 13:00:38 SWAP_WARN: 2136016
2024-02-05 13:15:36 SWAP_WARN: 2051536
2024-02-05 13:30:35 MEM_CRIT: 27203764 - restart mariadb-server
2024-02-05 13:30:40 SWAP_CRIT: 2625536 - restart mariadb-server
2024-02-05 13:45:33 MEM_CRIT: 28711708 - restart mariadb-server
2024-02-05 13:45:36 SWAP_CRIT: 2602480 - restart mariadb-server
2024-02-05 14:00:38 MEM_CRIT: 29051868 - restart mariadb-server
2024-02-05 14:00:42 SWAP_CRIT: 2609768 - restart mariadb-server
2024-02-05 14:15:35 MEM_CRIT: 34405256 - restart mariadb-server
2024-02-05 14:15:40 SWAP_WARN: 2447876
2024-02-05 14:30:37 MEM_CRIT: 21432660 - restart mariadb-server
2024-02-05 14:30:41 SWAP_WARN: 2426100
2024-02-05 14:45:35 SWAP_WARN: 2412168
2024-02-05 15:00:36 MEM_CRIT: 26707468 - restart mariadb-server
2024-02-05 15:00:40 SWAP_WARN: 2418920
2024-02-05 15:15:37 MEM_CRIT: 26416144 - restart mariadb-server
2024-02-05 15:15:41 SWAP_WARN: 2405424
2024-02-05 15:30:34 MEM_CRIT: 31726064 - restart mariadb-server
2024-02-05 15:30:38 SWAP_WARN: 2479700
2024-02-05 15:45:37 MEM_CRIT: 23153288 - restart mariadb-server
2024-02-05 15:45:40 SWAP_WARN: 2450004
2024-02-05 16:00:38 MEM_CRIT: 32272416 - restart mariadb-server
2024-02-05 16:00:43 SWAP_CRIT: 2606936 - restart mariadb-server
2024-02-05 16:30:37 MEM_CRIT: 28644620 - restart mariadb-server
2024-02-05 16:45:37 MEM_CRIT: 28760484 - restart mariadb-server
2024-02-05 17:15:01 CRASHED: start mariadb-server
2024-02-05 17:45:37 MEM_CRIT: 23925420 - restart mariadb-server
2024-02-05 18:00:35 MEM_CRIT: 29372856 - restart mariadb-server
2024-02-05 18:30:36 MEM_CRIT: 29184744 - restart mariadb-server
2024-02-05 19:00:01 CRASHED: start mariadb-server
2024-02-05 19:30:38 MEM_CRIT: 24255240 - restart mariadb-server
2024-02-05 19:45:33 MEM_CRIT: 26680092 - restart mariadb-server
2024-02-05 20:00:39 MEM_CRIT: 25893060 - restart mariadb-server
2024-02-05 20:15:40 MEM_CRIT: 33069852 - restart mariadb-server
2024-02-05 20:30:39 MEM_CRIT: 33667204 - restart mariadb-server
2024-02-05 20:45:34 MEM_CRIT: 24988640 - restart mariadb-server
2024-02-05 21:15:34 MEM_CRIT: 26416056 - restart mariadb-server

What is your mariadb configuration my_print_defaults --mysqld?

Your 4k table_open_cache appears insufficient for the tables actually being used.

Try enabling the performance_schema memory instrumentation. If this shows similar figures to Memory_used, install dgbsyms with package, and use bcc's memleak try an interval of 1 minute.

What a previous version of MariaDB running ok on your workload? Which version?

--socket=/run/mysqld/mysqld.sock
--pid-file=/run/mysqld/mysqld.pid
--basedir=/usr
--log_error=/var/log/mysql/error.log
--expire_logs_days=10
--character-set-server=utf8mb4
--collation-server=utf8mb4_general_ci
--innodb_buffer_pool_size=1G
--innodb_log_file_size=256M
--innodb_buffer_pool_instances=1
--innodb_flush_log_at_trx_commit=2
--tmp_table_size=256M
--table_open_cache=4000
--key_buffer_size=32M
--join_buffer_size=4M
--query_cache_limit=8M
--query_cache_size=128M
--open_files_limit=48000
--max_heap_table_size=256M
--myisam_sort_buffer_size=512M
--slow_query_log_file=/var/log/mysql/mariadb-slow.log
--long_query_time=10
--log_slow_rate_limit=1000
--log-queries-not-using-indexes
--max_connections=500
--tmpdir=/var/tmp
--myisam_repair_threads=2
--low_priority_updates=1
--max_allowed_packet=64M
--performance_schema=ON
--ssl_cert=/etc/mysql/ssl/bnet008.b-net.cloud.crt
--ssl_key=/etc/mysql/ssl/bnet008.b-net.cloud-nopw.key
--ssl_ca=/etc/mysql/ssl/mysql_2020_bundle.crt

@daniel Black why do you think, increasing table_open_cache will reduce the amount of memory leaks during sequential INSERT statements?

> why do you think, increasing table_open_cache will reduce the amount of memory

It would potentially reduce memory fragmentation, and it if somehow reduces the leak, then it could be a cause.

Aside min_examined_row_limit can reduce the slow query log to something more manageable.

Can you show the table structure, the form of the insert statements and the triggers? Change the fieldnames/table names (consistently) if you don't want to show them publicly.