Hello dear Percona team,
On our PMM3 deployment, we can see that the “pmm-agent“ is running some strange queries on MySQL databases. These strange queries are all failing. For example:
SELECT UNIX_TIMESTAMP(ts), UNIX_TIMESTAMP(NOW(6)), server_id
from `heartbeat`.`heartbeat`;
SHOW ENGINE TOKUDB STATUS;
SELECT @@query_response_time_stats;
Checking on some random databases being monitored by PMM3, we do not have the “heartbeat“ schema created in none. Also, we do not use the TokuDB storage engine, at all.
The question is: Why PMM3 is running those queries, and is there a way to disable them?
Thanks.
Hello @FabricioPedrosoJorge,
The heartbeat query is used by the mysql_exporter for more accurate replication lag calculations. If you are not using pt-heartbeat, that’s fine, the lag then comes from SHOW REPLICA STATUS. But the query must execute on a regular basis because you might add pt-heartbeat tomorrow.
The TokuDB query is for a dead MySQL engine, and there is an open issue to have that removed.
The last query for query_response_time is for a plugin in 5.7 which is not compatible in 8.0. I agree, if you have an 8.0+ system, this query should not be running. There is an open issue on this as well.
There is no way to disable these queries. Their failure should not be impacting your systems in any way. Feel free to upvote/comment on the JIRA issues.