PMM not reporting InnoDB Contention stats for MySQL 8.0

General

Escalation

General

Escalation

Description

MySQL 8.037 InnoDB Contention satt s not being reported in PMM

Attachment show it working for MySQL 5.7.42 but not for MySQL 8.0.37

How to test

step 1: start latest PMM(It is 2.42.0 at present) as following using docker:

step 2: start MySQL 5.7 & 8.0 [Used PS8.0.36] using the following command:

step 3: add the following configuration parameters to my.sandbox.cnf file and restart MySQL

step 4: configure the node and add it to the PMM server. Please use the correct IP of the docker container:

To get IP from a docker container, please run the following command:

step 5: Add 5.7 & 8.0 MySQL to PMM server:

step 6: start sysbench against 5.7 & 8.0

step 7: Now navigate to /graph/d/mysql-innodb/mysql-innodb-details and open the InnoDB Contention pane, and check no graph & values are being displayed for 8.0 and that it is properly displaying for 5.7

How to document

None

AFFECTED CS IDs

CSTASK0017507

Attachments

Activity

Show:

Nurlan Moldomurov February 20, 2025 at 11:15 AM

Note: Add comment to tooltips of these panels that they doesn’t support MySQL 8.0

Nurlan Moldomurov January 20, 2025 at 9:36 AM

I’m not sure if it’s possible to remove some panels for particular version.

Tibor Korocz (Percona) January 17, 2025 at 1:16 PM

We discussed it with and the metrics are deprecated and we did not find any alternatives to them. Probably we have to remove these graphs for Mysql 8.

Nurlan Moldomurov December 5, 2024 at 12:36 PM

I Found this in parent commit of the one you shared.
Bug#32225367: RW_LOCK_STATS OPERATION HAS REGRESSION FROM 5.6, LOWER CACHE EFFICIENCY

In the term of CPU cache efficiency, often used shard counter "rw_lock_stats" is better to be sharded by "os_thread_get_curr_id() based" index (thread bonded) than "my_timer_cycles()" index (random). Because of the changing about shard index, regression seems to be caused from 5.7.5. (for 5.7): Change sharding method to os_thread_get_curr_id() based and optimize, for compatibility (for 8.0): Remove rw_lock_stats (the best for performance). And deprecated outputs as always 0.