Debian 11 - MySQL OOM Killer Activation During Large Query Execution
After trying multiple solutions online, I still can't figure this out. I'm running Debian 11 with MySQL 8.0 and I've recently encountered a troubling scenario where the Out Of Memory (OOM) killer is terminating the MySQL process while executing large `JOIN` queries on sizable tables. The tables involved have around 1 million rows each, and the query looks like this: ```sql SELECT a.*, b.* FROM table_a a JOIN table_b b ON a.id = b.a_id WHERE a.created_at > '2023-01-01' AND b.status = 'active'; ``` I've tried increasing the `innodb_buffer_pool_size` to 2G, which is half of my available RAM (4G), but the scenario continues. The MySQL process is using around 3.5G of memory before the OOM killer intervenes. I’ve also adjusted `tmp_table_size` and `max_heap_table_size` to 512M, as I read that could help with large in-memory operations. When I check the system logs (`/var/log/syslog`), I see messages like: ``` [... MySQL] Out of memory: Kill process 1234 (mysqld) score 950 or sacrifice child ``` I’ve confirmed that there are no other resource-intensive processes running, and my swap space is set to 2G, but it seems insufficient during these large query executions. I’m considering adding more RAM or optimizing the query, but I’m unsure where to start. Any advice on how to prevent the OOM killer from terminating MySQL during these queries would be greatly appreciated. Should I tune additional parameters or adopt a different approach to handling large datasets? For context: I'm using Sql on Windows.