Hi support team,

A high level summary of the problem:

At 1:xx a.m. daily, some transactions take place at node 1, with select statements involved and transaction isolation level are repeatable read.

Node 2 slave thread memory consumption bumped up by ~2GB per day during this batch job execution, and such memory is not released.

We are unable to capture what was running at node 2. The information_summary.processlist.info_binary is NULL throughout the observation period.

Thanks and best regards,

Lawrence

frelist Is wsrep-slave-thread=128 in every node ?

Yes, but we recently we have reduced it match with the # of vCPUs and the situation remains the same.

I got a small reproducible case as in the attached file:

1. A table called t2 is created.
2. An insert w/ 10mil records via the stored procedure InsertIntoLknmT2_bind_savept() caused increase in node 2's memory utilization, whenever the SP was executed for the first & second time.
3. An SP Update_LknmT2_bind_savept was executed twice. Each time, there was rapid increase in memory utilization at node 2, during commit.
4. An SP Update_LknmT2_bind was executed twice. Each time, there was rapid increase in memory utilization at node 2, during commit.

It appears that the committing after running large batch of INSERT or UPDATE can lead to such situation, regardless of the presence of savepoint / release savepoint.

Thanks and best regards,

Lawrence

Investigation-2025-04-03.txt

In the previously attached file, the same insert / update is executed 10mil times, in a single transaction. The SQLs are written using bind variable. In this situation, will the memory used to parse the SQL be allocated for the first SQL, and re-used for the rest of SQLs within that same transaction, or will the memory used to parse the SQL be multiplied by 10mil times, since they are in the same transaction?

I raise the above query because it can be observed that there is a sharp rise in memory utilization, even though only a single INSERT/UPDATE SQL skeleton is used.