ilog_index_expire_time

ilog_index_expire_time specifies the validity period of ilog files on OBServer nodes. Expired files can no longer be read.

Considerations

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 occupied if partitions are repeatedly created and dropped.

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 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.

Examples

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