ilog_index_expire_time

ilog_index_expire_time specifies the validity period of ilog files cached on an OBServer node.

In OceanBase Database, file_id_cache caches the metadata of all ilog files and records the starting log ID and timestamp of each partition in the ilog files. By default, file_id_cache is cleaned only when ilog files are deleted. Therefore, on an OBServer node with a large disk, file_id_cache is likely to occupy large memory space. More memory space is required if partitions are repeatedly created and deleted.

You can use the ilog_index_expire_time parameter to free up some of the memory space occupied by file_id_cache. ilog_index_expire_time specifies the validity period of ilog files cached on an OBServer node. After the validity period of an ilog file ends, the ilog file is no longer cached in file_id_cache, which reduces the memory usage.

Take note of the following information when you set this parameter:

• If you decrease the value of this parameter, the system immediately cleans the expired memory space occupied by file_id_cache. You can query the size of space identified by ob_csr_file_id_cache to check the memory usage.

• If you increase the value of this parameter, file_id_cache caches ilog files within a larger time range after the relevant OBServer node is restarted.

Example

obclient> ALTER SYSTEM SET ilog_index_expire_time = '7d';