3.4 MGM API Data Structures

This section provides information about the data structures defined by the MGM API.

• The ndb_logevent Structure

• The ndb_mgm_node_state Structure

• The ndb_mgm_node_state2 Structure

• The ndb_mgm_cluster_state Structure

• The ndb_mgm_cluster_state2 Structure

• The ndb_mgm_reply Structure

The ndb_logevent Structure

Description

This structure models a Cluster log event, and is used for storing and retrieving log event information.

Definition.  ndb_logevent has 8 members, the first 7 of which are shown in the following list:

• void* handle: An NdbLogEventHandle, set by ndb_logevent_get_next(). This handle is used only for purposes of comparison.

• type: Tells which type of event (Ndb_logevent_type) this is.

• unsigned time: The time at which the log event was registered with the management server.

• category: The log event category (ndb_mgm_event_category).

• severity: The log event severity (ndb_mgm_event_severity).

• unsigned level: The log event level. This is a value in the range of 0 to 15, inclusive.

• unsigned source_nodeid: The node ID of the node that reported this event.

The 8^th member of this structure contains data specific to the log event, and is dependent on its type. It is defined as the union of a number of data structures, each corresponding to a log event type. Which structure to use is determined by the value of type, and is shown in the following table:

Table 3.7 Type Ndb_logevent_type values and structures used

Ndb_logevent_type Value	Structure
NDB_LE_Connected	Connected: unsigned node
NDB_LE_Disconnected	Disconnected: unsigned node
NDB_LE_CommunicationClosed	CommunicationClosed: unsigned node
NDB_LE_CommunicationOpened	CommunicationOpened: unsigned node
NDB_LE_ConnectedApiVersion	ConnectedApiVersion: unsigned node unsigned version
NDB_LE_GlobalCheckpointStarted	GlobalCheckpointStarted: unsigned gci
NDB_LE_GlobalCheckpointCompleted	GlobalCheckpointCompleted: unsigned gci
NDB_LE_LocalCheckpointStarted	LocalCheckpointStarted: unsigned lci unsigned keep_gci unsigned restore_gci
NDB_LE_LocalCheckpointCompleted	LocalCheckpointCompleted: unsigned lci
NDB_LE_LCPStoppedInCalcKeepGci	LCPStoppedInCalcKeepGci: unsigned data
NDB_LE_LCPFragmentCompleted	LCPFragmentCompleted: unsigned node unsigned table_id unsigned fragment_id
NDB_LE_UndoLogBlocked	UndoLogBlocked: unsigned acc_count unsigned tup_count
NDB_LE_NDBStartStarted	NDBStartStarted: unsigned version
NDB_LE_NDBStartCompleted	NDBStartCompleted: unsigned version
NDB_LE_STTORRYRecieved	STTORRYRecieved: [NONE]
NDB_LE_StartPhaseCompleted	StartPhaseCompleted: unsigned phase unsigned starttype
NDB_LE_CM_REGCONF	CM_REGCONF: unsigned own_id unsigned president_id unsigned dynamic_id
NDB_LE_CM_REGREF	CM_REGREF: unsigned own_id unsigned other_id unsigned cause
NDB_LE_FIND_NEIGHBOURS	FIND_NEIGHBOURS: unsigned own_id unsigned left_id unsigned right_id unsigned dynamic_id
NDB_LE_NDBStopStarted	NDBStopStarted: unsigned stoptype
NDB_LE_NDBStopCompleted	NDBStopCompleted: unsigned action unsigned signum
NDB_LE_NDBStopForced	NDBStopForced: unsigned action unsigned signum unsigned error unsigned sphase unsigned extra
NDB_LE_NDBStopAborted	NDBStopAborted: [NONE]
NDB_LE_StartREDOLog	StartREDOLog: unsigned node unsigned keep_gci unsigned completed_gci unsigned restorable_gci
NDB_LE_StartLog	StartLog: unsigned log_part unsigned start_mb unsigned stop_mb unsigned gci
NDB_LE_UNDORecordsExecuted	UNDORecordsExecuted: unsigned block unsigned data1 unsigned data2 unsigned data3 unsigned data4 unsigned data5 unsigned data6 unsigned data7 unsigned data8 unsigned data9 unsigned data10
NDB_LE_NR_CopyDict	NR_CopyDict: [NONE]
NDB_LE_NR_CopyDistr	NR_CopyDistr: [NONE]
NDB_LE_NR_CopyFragsStarted	NR_CopyFragsStarted: unsigned dest_node
NDB_LE_NR_CopyFragDone	NR_CopyFragDone: unsigned dest_node unsigned table_id unsigned fragment_id
NDB_LE_NR_CopyFragsCompleted	NR_CopyFragsCompleted: unsigned dest_node
NDB_LE_NodeFailCompleted	NodeFailCompleted: unsigned block unsigned failed_node unsigned completing_node (For block and completing_node, 0 is interpreted as “all”.)
NDB_LE_NODE_FAILREP	NODE_FAILREP: unsigned failed_node unsigned failure_state
NDB_LE_ArbitState	ArbitState: unsigned code unsigned arbit_node unsigned ticket_0 unsigned ticket_1
NDB_LE_ArbitResult	ArbitResult: unsigned code unsigned arbit_node unsigned ticket_0 unsigned ticket_1
NDB_LE_GCP_TakeoverStarted	GCP_TakeoverStarted: [NONE]
NDB_LE_GCP_TakeoverCompleted	GCP_TakeoverCompleted: [NONE]
NDB_LE_LCP_TakeoverStarted	LCP_TakeoverStarted: [NONE]
NDB_LE_TransReportCounters	TransReportCounters: unsigned trans_count unsigned commit_count unsigned read_count unsigned simple_read_count unsigned write_count unsigned attrinfo_count unsigned conc_op_count unsigned abort_count unsigned scan_count unsigned range_scan_count
NDB_LE_OperationReportCounters	OperationReportCounters: unsigned ops
NDB_LE_TableCreated	TableCreated: unsigned table_id
NDB_LE_JobStatistic	JobStatistic: unsigned mean_loop_count
NDB_LE_SendBytesStatistic	SendBytesStatistic: unsigned to_node unsigned mean_sent_bytes
NDB_LE_ReceiveBytesStatistic	ReceiveBytesStatistic: unsigned from_node unsigned mean_received_bytes
NDB_LE_MemoryUsage	MemoryUsage: int gth unsigned page_size_kb unsigned pages_used unsigned pages_total unsigned block
NDB_LE_TransporterError	TransporterError: unsigned to_node unsigned code
NDB_LE_TransporterWarning	TransporterWarning: unsigned to_node unsigned code
NDB_LE_MissedHeartbeat	MissedHeartbeat: unsigned node unsigned count
NDB_LE_DeadDueToHeartbeat	DeadDueToHeartbeat: unsigned node
NDB_LE_WarningEvent	WarningEvent: [NOT YET IMPLEMENTED]
NDB_LE_SentHeartbeat	SentHeartbeat: unsigned node
NDB_LE_CreateLogBytes	CreateLogBytes: unsigned node
NDB_LE_InfoEvent	InfoEvent: [NOT YET IMPLEMENTED]
NDB_LE_EventBufferStatus (Prior to NDB 7.5)	EventBufferStatus:: unsigned usage unsigned alloc unsigned max unsigned apply_gci_l unsigned apply_gci_h unsigned latest_gci_l unsigned latest_gci_h
NDB_LE_EventBufferStatus2 (NDB 7.5)	EventBufferStatus2: unsigned usage unsigned alloc unsigned max unsigned latest_consumed_epoch_l unsigned latest_consumed_epoch_h unsigned latest_buffered_epoch_l unsigned latest_buffered_epoch_h unsigned ndb_reference unsigned report_reason report_reason is one of NO_REPORT, COMPLETELY_BUFFERING, PARTIALLY_DISCARDING, COMPLETELY_DISCARDING, PARTIALLY_BUFFERING, BUFFERED_EPOCHS_OVER_THRESHOLD, ENOUGH_FREE_EVENTBUFFER, or LOW_FREE_EVENTBUFFER; see Event Buffer Reporting in the Cluster Log, for descriptions of these values
NDB_LE_BackupStarted	BackupStarted: unsigned starting_node unsigned backup_id
NDB_LE_BackupFailedToStart	BackupFailedToStart: unsigned starting_node unsigned error
NDB_LE_BackupCompleted	BackupCompleted: unsigned starting_node unsigned backup_id unsigned start_gci unsigned stop_gci unsigned n_records unsigned n_log_records unsigned n_bytes unsigned n_log_bytes
NDB_LE_BackupAborted	BackupAborted: unsigned starting_node unsigned backup_id unsigned error
NDB_LE_SingleUser	SingleUser: unsigned type unsigned node_id
NDB_LE_StartReport	StartReport: unsigned report_type unsigned remaining_time unsigned bitmask_size unsigned bitmask_data[1]

The ndb_mgm_node_state Structure

Description

Provides information on the status of a Cluster node.

Definition.  This structure contains the following members:

• int node_id: The cluster node's node ID.

• enum ndb_mgm_node_type node_type: The node type.

  See The ndb_mgm_node_type Type, for permitted values.

• enum ndb_mgm_node_status node_status: The node's status.

  See The ndb_mgm_node_status Type, for permitted values.

• int start_phase: The start phase.

  This is valid only if the node_type is NDB_MGM_NODE_TYPE_NDB and the node_status is NDB_MGM_NODE_STATUS_STARTING.

• int dynamic_id: The ID for heartbeats and master takeover.

  Valid only for data (ndbd) nodes.

• int node_group: The node group to which the node belongs.

  Valid only for data (ndbd) nodes.

• int version: Internal version number.

• int connect_count: The number of times this node has connected to or disconnected from the management server.

• char connect_address[]: The IP address of this node as seen by the other nodes in the cluster.

• int mysql_version: The MySQL version number, expressed as an integer (for example: 80200). Applies only to SQL nodes.

• int is_single_user: The node ID of the API or SQL node having exclusive access when the cluster is in single user mode. Does not otherwise apply. Added in NDB 8.0.

The ndb_mgm_node_state2 Structure

Description

Provides information on the status of a Cluster node.

Definition.  This structure contains the following members:

• int node_id: The cluster node's node ID.

• enum ndb_mgm_node_type node_type: The node type.

  See The ndb_mgm_node_type Type, for permitted values.

• enum ndb_mgm_node_status node_status: The node's status.

  See The ndb_mgm_node_status Type, for permitted values.

• int start_phase: The start phase.

  This is valid only if the node_type is NDB_MGM_NODE_TYPE_NDB and the node_status is NDB_MGM_NODE_STATUS_STARTING.

• int dynamic_id: The ID for heartbeats and master takeover.

  Valid only for data (ndbd) nodes.

• int node_group: The node group to which the node belongs.

  Valid only for data (ndbd) nodes.

• int version: Internal version number.

• int connect_count: The number of times this node has connected to or disconnected from the management server.

• int mysql_version: The MySQL version number, expressed as an integer (for example: 80200). Applies only to SQL nodes.

• int is_single_user: The node ID of the API or SQL node having exclusive access when the cluster is in single user mode. Does not otherwise apply.

• char connect_address[]: The IP address of this node as seen by the other nodes in the cluster.

The ndb_mgm_cluster_state Structure

Description

Provides information on the status of all Cluster nodes. This structure is returned by ndb_mgm_get_status().

Definition.  This structure has the following two members:

• int no_of_nodes: The number of elements in the node_states array.

• struct ndb_mgm_node_state node_states[]: An array containing the states of the nodes.

  Each element of this array is an ndb_mgm_node_state structure.

See ndb_mgm_get_status().

The ndb_mgm_cluster_state2 Structure

Description

Provides information on the status of all Cluster nodes. This structure is returned by ndb_mgm_get_status3(), and was added in NDB 8.0.

Definition.  This structure has the following two members:

• int no_of_nodes: The number of elements in the node_states array.

• struct ndb_mgm_node_state2 node_states[]: An array containing the states of the nodes.

  Each element of this array is an ndb_mgm_node_state2 structure.

See ndb_mgm_get_status3().

The ndb_mgm_reply Structure

Description

Contains response information, consisting of a response code and a corresponding message, from the management server.

Definition.  This structure contains two members, as shown here:

• int return_code: For a successful operation, this value is 0; otherwise, it contains an error code.

  For error codes, see The ndb_mgm_error Type.

• char message[256]: contains the text of the response or error message.

See ndb_mgm_get_latest_error(), and ndb_mgm_get_latest_error_msg().