Identifying Unused Table Files
Vector automatically removes files that are no longer used (for example, after a table or column is dropped).
System crashes, however, may cause unused table files that should have been deleted to be left on disk. If disk space is low you may need to remove such files.
Follow these steps to find and remove unused table files:
1. Connect to the database and issue the following SQL statement:
CALL VECTORWISE(CLEANUP_UNUSED_FILES)
This system command scans all locations recursively to find files that do not belong to any tables. It renames such files by adding "unused_" prefix. This command can be executed on a working system.
2. Make sure that the system is running correctly without these files.
3. Remove the unused files.
Note: CLEANUP_UNUSED_FILES does not mark unreleased files that may still be needed by a transaction. So using this system call may not help you to free space if there are long-running or hanging transactions in the system.