The "max-query-length" parameter is not effective


Hi, I faced an error called “EXPLAIN failed because the query was too long and trimmed. Set max-query-length to a larger value.” while i was used PMM QAN/explain on MySQL long-length query.
After that, I re-added the MySQL node and set “max-query-length” to “-1”, but the error still came up.

Looking forward for your reply, thanks!

Steps to Reproduce:

  1. Add a new MySQL node called “prod2” and set “max-query-length” to “-1” .
  2. Remove old MySQL node called “prod”


PMM Version: 2.41.2
MySQL Version: 8.0.26

Expected Result:

Expected the Result of PMM QAN/explain with long-length query work well.

1 Like

@wayne1 , this sounds like a bug.
Can you report a bug in our Jira at so we can reproduce it?
It will be good to have also an example of the query you had here and the client version (if it’s not the same as the server )

Hello, what data source was used? if it’s performance schema, there is also variable that should be updated on DB side performance_schema_max_digest_length