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

Percona Monitoring and Management (PMM) PMM 2.x
1

Description:

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!

Snipaste_2024-05-09_14-43-30
Snipaste_2024-05-09_14-43-301522×432 29.4 KB

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”

Version:

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.

2 Likes
2

@wayne1 , this sounds like a bug.
Can you report a bug in our Jira at https://perconadev.atlassian.net/ 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 )

3

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 https://dev.mysql.com/doc/refman/8.0/en/performance-schema-system-variables.html