Memory usage control

The current version of OceanBase Database can track the memory usage of a single SQL statement. When memory usage exceeds a specified threshold, the system returns an error and stops the SQL statement execution to prevent out-of-memory (OOM) issues or for OOM troubleshooting.

Adjust the memory usage threshold for the execution of a single SQL statement

OceanBase Database allows you to use the tenant-level parameter query_memory_limit_percentage to specify the maximum percentage of memory in the tenant available for a single SQL statement. The default value is 50, indicating that the system returns an error and stops the SQL statement execution when the memory used by a single SQL statement exceeds 50% of the tenant memory. You can adjust the parameter

by performing the following steps based on your business needs:

1. Log in to a user tenant of the cluster as the tenant administrator.

   Note

   The administrator user is the root user in MySQL mode and the SYS user in Oracle mode.

   Here is an example:

   obclient -h172.30.xxx.xxx -P2883 -uroot@mysqltenant#obdemo -pxxxx -A
   

2. Query the value of the query_memory_limit_percentage parameter.

   obclient> SHOW PARAMETERS LIKE '%query_memory_limit_percentage%';
   

3. Adjust the value of the query_memory_limit_percentage parameter.

   Here is an example:

   obclient> ALTER SYSTEM SET query_memory_limit_percentage = 50;
   

References

query_memory_limit_percentage