def _undo_add_shard_mapping(shard_mapping_id, table_name, column_name, range_check=False, update_only=False): """Add a table to a shard mapping. :param shard_mapping_id: The shard mapping id to which the input table is attached. :param table_name: The table being sharded. :param column_name: The column whose value is used in the sharding scheme being applied :param range_check: Indicates if range check should be turned on for this table. :param update_only: Only update the state store and skip adding range checks. :return: True if the the table was successfully added. False otherwise. """ if range_check and not update_only: sharding_defn = ShardMapping.fetch_shard_mapping_defn(shard_mapping_id) if sharding_defn: _, sharding_type, global_group_id = sharding_defn SHARD_METADATA_VERIFIER.drop_shard_range_trigger( global_group_id, sharding_type, table_name, column_name )
def _undo_add_shard_mapping(shard_mapping_id, table_name, column_name, range_check=False, update_only=False): """Add a table to a shard mapping. :param shard_mapping_id: The shard mapping id to which the input table is attached. :param table_name: The table being sharded. :param column_name: The column whose value is used in the sharding scheme being applied :param range_check: Indicates if range check should be turned on for this table. :param update_only: Only update the state store and skip adding range checks. :return: True if the the table was successfully added. False otherwise. """ if range_check and not update_only: sharding_defn = ShardMapping.fetch_shard_mapping_defn(shard_mapping_id) if sharding_defn: _, sharding_type, global_group_id = sharding_defn SHARD_METADATA_VERIFIER.drop_shard_range_trigger( global_group_id, sharding_type, table_name, column_name)
def verify_and_fetch_shard(shard_id): """Find out if the shard_id exists and return the sharding specification for it. If it does not exist throw an exception. :param shard_id: The ID for the shard whose specification needs to be fetched. :return: The sharding specification class representing the shard ID. :raises: ShardingError if the shard ID is not found. """ #Here the underlying sharding specification might be a RANGE #or a HASH. The type of sharding specification is obtained from the #shard mapping. range_sharding_spec = RangeShardingSpecification.fetch(shard_id) if range_sharding_spec is None: raise _errors.ShardingError(SHARD_NOT_FOUND % (shard_id, )) #Fetch the shard mappings and use them to find the type of sharding #scheme. shard_mappings = ShardMapping.fetch_by_id( range_sharding_spec.shard_mapping_id ) if shard_mappings is None: raise _errors.ShardingError( SHARD_MAPPING_NOT_FOUND % ( range_sharding_spec.shard_mapping_id, ) ) #Fetch the shard mapping definition. There is only one shard mapping #definition associated with all of the shard mappings. shard_mapping_defn = ShardMapping.fetch_shard_mapping_defn( range_sharding_spec.shard_mapping_id ) if shard_mapping_defn is None: raise _errors.ShardingError( SHARD_MAPPING_DEFN_NOT_FOUND % ( range_sharding_spec.shard_mapping_id, ) ) shard = Shards.fetch(shard_id) if shard is None: raise _errors.ShardingError(SHARD_NOT_FOUND % (shard_id, )) #Both of the shard_mappings retrieved will be of the same sharding #type. Hence it is safe to use one of them to retireve the sharding type. if shard_mappings[0].type_name == "HASH": return HashShardingSpecification.fetch(shard_id), \ shard, shard_mappings, shard_mapping_defn else: return range_sharding_spec, shard, shard_mappings, shard_mapping_defn
def verify_and_fetch_shard(shard_id): """Find out if the shard_id exists and return the sharding specification for it. If it does not exist throw an exception. :param shard_id: The ID for the shard whose specification needs to be fetched. :return: The sharding specification class representing the shard ID. :raises: ShardingError if the shard ID is not found. """ #Here the underlying sharding specification might be a RANGE #or a HASH. The type of sharding specification is obtained from the #shard mapping. range_sharding_spec = RangeShardingSpecification.fetch(shard_id) if range_sharding_spec is None: raise _errors.ShardingError(SHARD_NOT_FOUND % (shard_id, )) #Fetch the shard mappings and use them to find the type of sharding #scheme. shard_mappings = ShardMapping.fetch_by_id( range_sharding_spec.shard_mapping_id) if shard_mappings is None: raise _errors.ShardingError(SHARD_MAPPING_NOT_FOUND % (range_sharding_spec.shard_mapping_id, )) #Fetch the shard mapping definition. There is only one shard mapping #definition associated with all of the shard mappings. shard_mapping_defn = ShardMapping.fetch_shard_mapping_defn( range_sharding_spec.shard_mapping_id) if shard_mapping_defn is None: raise _errors.ShardingError(SHARD_MAPPING_DEFN_NOT_FOUND % (range_sharding_spec.shard_mapping_id, )) shard = Shards.fetch(shard_id) if shard is None: raise _errors.ShardingError(SHARD_NOT_FOUND % (shard_id, )) #Both of the shard_mappings retrieved will be of the same sharding #type. Hence it is safe to use one of them to retireve the sharding type. if shard_mappings[0].type_name == "HASH": return HashShardingSpecification.fetch(shard_id), \ shard, shard_mappings, shard_mapping_defn else: return range_sharding_spec, shard, shard_mappings, shard_mapping_defn
def _add_shard(shard_mapping_id, groupid_lb_list, state, update_only=False): """Add the RANGE shard specification. This represents a single instance of a shard specification that maps a key RANGE to a server. :param shard_mapping_id: The unique identification for a shard mapping. :param groupid_lb_list: The list of group_id, lower_bounds pairs in the format, group_id/lower_bound, group_id/lower_bound... . :param state: Indicates whether a given shard is ENABLED or DISABLED :param update_only: Only update the state store and skip adding range checks. :return: True if the add succeeded. False otherwise. :raises: ShardingError If the group on which the shard is being created does not exist, If the shard_mapping_id is not found, If adding the shard definition fails, If the state of the shard is an invalid value, If the range definition is invalid. """ shard_mapping = ShardMapping.fetch_shard_mapping_defn(shard_mapping_id) if shard_mapping is None: raise _errors.ShardingError(SHARD_MAPPING_NOT_FOUND % \ (shard_mapping_id, )) schema_type = shard_mapping[1] if len(RangeShardingSpecification.list(shard_mapping_id)) != 0: raise _errors.ShardingError(SHARDS_ALREADY_EXIST) group_id_list, lower_bound_list = \ _utils.get_group_lower_bound_list(groupid_lb_list) if (len(group_id_list) != len(lower_bound_list)) and\ schema_type == "RANGE": raise _errors.ShardingError(LOWER_BOUND_GROUP_ID_COUNT_MISMATCH) if len(lower_bound_list) != 0 and schema_type == "HASH": raise _errors.ShardingError(LOWER_BOUND_AUTO_GENERATED) if schema_type in Shards.VALID_RANGE_SHARDING_TYPES: for lower_bound in lower_bound_list: if not SHARDING_DATATYPE_HANDLER[schema_type].\ is_valid_lower_bound(lower_bound): raise _errors.ShardingError( INVALID_LOWER_BOUND_VALUE % (lower_bound, )) state = state.upper() if state not in Shards.VALID_SHARD_STATES: raise _errors.ShardingError(INVALID_SHARD_STATE % (state, )) for index, group_id in enumerate(group_id_list): shard = Shards.add(group_id, state) shard_id = shard.shard_id if schema_type == "HASH": HashShardingSpecification.add( shard_mapping_id, shard_id ) _LOGGER.debug( "Added Shard (map id = %s, id = %s).", shard_mapping_id, shard_id ) else: range_sharding_specification = \ SHARDING_SPECIFICATION_HANDLER[schema_type].add( shard_mapping_id, lower_bound_list[index], shard_id ) _LOGGER.debug( "Added Shard (map id = %s, lower bound = %s, id = %s).", range_sharding_specification.shard_mapping_id, range_sharding_specification.lower_bound, range_sharding_specification.shard_id ) if not update_only: #If the shard is added in a DISABLED state do not setup replication #with the primary of the global group. Basically setup replication only #if the shard is ENABLED. if state == "ENABLED": _setup_shard_group_replication(shard_id) if not update_only: #Add the shard limits into the metadata present in each of the shards. _events.trigger_within_procedure( ADD_SHARD_RANGE_CHECK, shard_mapping_id, schema_type )
def _add_shard(shard_mapping_id, groupid_lb_list, state): """Add the RANGE shard specification. This represents a single instance of a shard specification that maps a key RANGE to a server. :param shard_mapping_id: The unique identification for a shard mapping. :param groupid_lb_list: The list of group_id, lower_bounds pairs in the format, group_id/lower_bound, group_id/lower_bound... . :param state: Indicates whether a given shard is ENABLED or DISABLED :return: True if the add succeeded. False otherwise. :raises: ShardingError If the group on which the shard is being created does not exist, If the shard_mapping_id is not found, If adding the shard definition fails, If the state of the shard is an invalid value, If the range definition is invalid. """ shard_mapping = ShardMapping.fetch_shard_mapping_defn(shard_mapping_id) if shard_mapping is None: raise _errors.ShardingError(SHARD_MAPPING_NOT_FOUND % \ (shard_mapping_id, )) schema_type = shard_mapping[1] if len(RangeShardingSpecification.list(shard_mapping_id)) != 0: raise _errors.ShardingError(SHARDS_ALREADY_EXIST) group_id_list, lower_bound_list = \ _utils.get_group_lower_bound_list(groupid_lb_list) if (len(group_id_list) != len(lower_bound_list)) and\ schema_type == "RANGE": raise _errors.ShardingError(LOWER_BOUND_GROUP_ID_COUNT_MISMATCH) if len(lower_bound_list) != 0 and schema_type == "HASH": raise _errors.ShardingError(LOWER_BOUND_AUTO_GENERATED) if schema_type in Shards.VALID_RANGE_SHARDING_TYPES: for lower_bound in lower_bound_list: if not SHARDING_DATATYPE_HANDLER[schema_type].\ is_valid_lower_bound(lower_bound): raise _errors.ShardingError(INVALID_LOWER_BOUND_VALUE % (lower_bound, )) state = state.upper() if state not in Shards.VALID_SHARD_STATES: raise _errors.ShardingError(INVALID_SHARD_STATE % (state, )) for index, group_id in enumerate(group_id_list): shard = Shards.add(group_id, state) shard_id = shard.shard_id if schema_type == "HASH": HashShardingSpecification.add(shard_mapping_id, shard_id) _LOGGER.debug("Added Shard (map id = %s, id = %s).", shard_mapping_id, shard_id) else: range_sharding_specification = \ SHARDING_SPECIFICATION_HANDLER[schema_type].add( shard_mapping_id, lower_bound_list[index], shard_id ) _LOGGER.debug( "Added Shard (map id = %s, lower bound = %s, id = %s).", range_sharding_specification.shard_mapping_id, range_sharding_specification.lower_bound, range_sharding_specification.shard_id) #If the shard is added in a DISABLED state do not setup replication #with the primary of the global group. Basically setup replication only #if the shard is ENABLED. if state == "ENABLED": _setup_shard_group_replication(shard_id)