Set Index Lock Mode Operation

• Unlocked - when lock mode is set to UNLOCK:

  • Any change to the index definition will be applied.
  • If the new index definition differs from the one stored on the server,
    the index will be updated and the data will be re-indexed using the new index definition.

• Locked (ignore) - when lock mode is set to LOCKED_IGNORE:

  • Index definition changes will Not be applied.
  • Modifying the index definition will return successfully and no error will be raised,
    however, no change will be made to the index definition on the server.

• Locked (error) - when lock mode is set to LOCKED_ERROR:

  • Index definitions changes will Not be applied.
  • An exception will be thrown upon trying to modify the index.

Consider the following scenario:

• Your client application defines and deploys a static-index upon application startup.

• After the application has started, you make a change to your index definition and re-indexing occurs.
  However, if the index lock mode is UNLOCK, the next time your application will start,
  it will reset the index definition back to the original version.

• Locking the index allows to make changes to the running index and prevents the application
  from setting it back to the previous definition upon startup. See the following steps:
  
  

  1. Run your application
  2. Modify the index definition on the server (from Studio, or from another application),
     and then set this index lock mode to LOCKED_IGNORE.
  3. A side-by-side replacement index is created on the server.
     It will index your dataset according to the new definition.
  4. At this point, if any instance of your original application is started,
     the code that defines and deploys the index upon startup will have no effect
     since the index is LOCKED.
  5. Once the replacement index is done indexing, it will replace the original index.

# Define the set lock mode operation
# Pass index name & lock mode
set_lock_mode_op = SetIndexesLockOperation(IndexLockMode.LOCKED_IGNORE, "Orders/Totals")

# Execute the operation by passing it to maintenance.send
# An exception will be thrown if index does not exist
store.maintenance.send(set_lock_mode_op)

# Lock mode is now set to 'LockedIgnore'
# Any modification done now to the index will Not be applied, and will Not throw

# Define the set lock mode operation, pass the parameters
set_lock_mode_op = SetIndexesLockOperation(IndexLockMode.LOCKED_ERROR, "Orders/Totals", "Orders/ByCompany")

# Execute the operation by passing it to maintenance.send
# An exception will be thrown if any of the specified indexes does not exist
store.maintenance.send(set_lock_mode_op)

# Lock mode is now set to 'LockedError' on both indexes
# Any modifications done now to either index will throw

class SetIndexesLockOperation(VoidMaintenanceOperation):
    def __init__(self, mode: IndexLockMode, *index_names: str): ...

class IndexLockMode(Enum):
    UNLOCK = "Unlock"
    LOCKED_IGNORE = "LockedIgnore"
    LOCKED_ERROR = "LockedError"

    def __str__(self):
        return self.value