29.12.12.3 The ndb_replication_applier_status Table

NDBCLUSTER exposes its internal replication applier state for observation using global status variables such as Ndb_replica_max_replicated_epoch and Ndb_api_trans_start_count_replica, but these values reflect the state of the default replication channel only. The ndb_replication_applier_status provides the same information, but on a per-channel basis; with the exception of CHANNEL_NAME, each column in this table corresponds to a server status variable; where applicable, this information is included in the column descriptions provided later in this section.

This table is an NDB-specific extension to the replication_applier_status table.

The ndb_replication_applier_status table has the columns shown and described in the following list:

• CHANNEL_NAME:

  The name of the replication channel. The default is an empty string ("").

• MAX_REPLICATED_EPOCH:

  The most recently committed NDB epoch on this replica. Ndb_replica_max_replicated_epoch shows this value for the default replication channel.

• API_WAIT_EXEC_COMPLETE_COUNT:

  The number of times this thread has been blocked while waiting for an operation by this SQL node to complete. Ndb_api_wait_exec_complete_count_replica shows this value for the default replication channel.

• API_WAIT_SCAN_RESULT_COUNT:

  The number of times this thread has been blocked while waiting for a scan-based signal by this SQL node. Ndb_api_wait_scan_result_count_replica shows this value for the default replication channel.

• API_WAIT_META_REQUEST_COUNT:

  The number of times this thread has been blocked waiting for a metadata-based signal by this SQL node. Ndb_api_wait_meta_request_count_replica shows this value for the default replication channel.

• API_WAIT_NANOS_COUNT:

  Cumulative time in nanoseconds spent waiting for some type of signal from the data nodes by this SQL node. Ndb_api_wait_nanos_count_replica shows this value for the default replication channel.

• API_BYTES_SENT_COUNT:

  The number of bytes sent to the data nodes by this SQL node. Ndb_api_bytes_sent_count_replica shows this value for the default replication channel.

• API_BYTES_RECEIVED_COUNT:

  The number of bytes received from the data nodes by this SQL node. Ndb_api_bytes_received_count_replica shows this value for the default replication channel.

• API_TRANS_START_COUNT:

  The number of transactions started by this SQL node. Ndb_api_trans_start_count_replica shows this value for the default replication channel.

• API_TRANS_COMMIT_COUNT:

  The number of transactions committed by this SQL node. Ndb_api_trans_commit_count_replica shows this value for the default replication channel.

• API_TRANS_ABORT_COUNT:

  The number of transactions aborted by this SQL node. Ndb_api_trans_abort_count_replica shows this value for the default replication channel.

• API_TRANS_CLOSE_COUNT:

  The number of transactions which have been closed by this SQL node; this value may be greater than the sum of API_TRANS_COMMIT_COUNT and API_TRANS_ABORT_COUNT. Ndb_api_trans_close_count_replica shows this value for the default replication channel.

• API_PK_OP_COUNT:

  The number of primary key operations which have been performed by this SQL node. Ndb_api_pk_op_count_replica shows this value for the default replication channel.

• API_UK_OP_COUNT:

  The number of unique key operations which have been performed by this SQL node. Ndb_api_uk_op_count_replica shows this value for the default replication channel.

• API_TABLE_SCAN_COUNT:

  The number of table scans which have been started by this SQL node. This includes scans of internal tables. Ndb_api_table_scan_count_replica shows this value for the default replication channel.

• API_RANGE_SCAN_COUNT:

  The number of range scans which have been started by this SQL node. Ndb_api_range_scan_count_replica shows this value for the default replication channel.

• API_PRUNED_SCAN_COUNT:

  The number of scans which have been pruned to a single partition by this SQL node. Ndb_api_pruned_scan_count_replica shows this value for the default replication channel.

• API_SCAN_BATCH_COUNT:

  The number of row batches which have been received by this SQL node. Ndb_api_scan_batch_count_replica shows this value for the default replication channel.

• API_READ_ROW_COUNT:

  The total number of rows which have been read by this SQL node. Ndb_api_read_row_count_replica shows this value for the default replication channel.

• API_TRANS_LOCAL_READ_ROW_COUNT:

  The total number of rows which have been read by this SQL node locally. Ndb_api_trans_local_read_row_count_replica shows this value for the default replication channel.

• API_ADAPTIVE_SEND_FORCED_COUNT:

  The number of adaptive sends which have been sent by this SQL node making use of forced send. Ndb_api_adaptive_send_forced_count_replica shows this value for the default replication channel.

• API_ADAPTIVE_SEND_UNFORCED_COUNT:

  The number of adaptive sends which have been sent by this SQL node without using forced send. Ndb_api_adaptive_send_unforced_count_replica shows this value for the default replication channel.

• API_ADAPTIVE_SEND_DEFERRED_COUNT:

  The number of adaptive sends which were not actually sent by this SQL node. Ndb_api_adaptive_send_deferred_count_replica shows this value for the default replication channel.

• CONFLICT_FN_MAX:

  The number of times that NDB replication “greater timestamp wins” conflict resolution has been applied to update and delete operations. Ndb_conflict_fn_max shows this value for the default replication channel.

• CONFLICT_FN_OLD:

  The number of times that NDB replication “same timestamp wins” conflict resolution has been applied. Ndb_conflict_fn_old shows this value for the default replication channel.

• CONFLICT_FN_MAX_DEL_WIN:

  The number of times that NDB replication conflict resolution based on the result of NDB$MAX_DELETE_WIN() has been applied to update and delete operations. Ndb_conflict_fn_max_del_win shows this value for the default replication channel.

• CONFLICT_FN_MAX_INS:

  The number of times that NDB replication “greater timestamp wins” conflict resolution has been applied to insert operations. Ndb_conflict_fn_max_ins shows this value for the default replication channel.

• CONFLICT_FN_MAX_DEL_WIN_INS:

  The number of times that NDB replication conflict resolution based on the result of NDB$MAX_DELETE_WIN_INS() has been applied to update and delete operations. Ndb_conflict_fn_max_del_win_ins shows this value for the default replication channel.

• CONFLICT_FN_EPOCH:

  The number of rows which have been found in conflict by the NDB$EPOCH() NDB replication conflict detection function. Ndb_conflict_fn_epoch shows this value for the default replication channel.

• CONFLICT_FN_EPOCH_TRANS:

  The number of rows which have been found in conflict by the NDB$EPOCH_TRANS() NDB replication conflict detection function. Ndb_conflict_fn_epoch_trans shows this value for the default replication channel.

• CONFLICT_FN_EPOCH2:

  The number of rows which have been found in conflict by the NDB$EPOCH2() NDB replication conflict detection function. Ndb_conflict_fn_epoch2 shows this value for the default replication channel.

• CONFLICT_FN_EPOCH2_TRANS:

  The number of rows which have been found in conflict by the NDB$EPOCH2_TRANS() NDB replication conflict detection function. Ndb_conflict_fn_epoch2_trans shows this value for the default replication channel.

• CONFLICT_TRANS_ROW_CONFLICT_COUNT:

  The number of rows which have been found to be in conflict by a transactional conflict function, including any rows which were included in or dependent on conflicting transactions. Ndb_conflict_trans_row_conflict_count shows this value for the default replication channel.

• CONFLICT_TRANS_ROW_REJECT_COUNT:

  The total number of rows which have been realigned after being found to be in conflict by a transactional conflict function, including CONFLICT_TRANS_ROW_CONFLICT_COUNT as well as any rows which were included in or dependent on conflicting transactions. Ndb_conflict_trans_row_reject_count shows this value for the default replication channel.

• CONFLICT_TRANS_REJECT_COUNT:

  The number of transactions which have been rejected after being found to be in conflict by a transactional conflict function. Ndb_conflict_trans_reject_count shows this value for the default replication channel.

• CONFLICT_TRANS_DETECT_ITER_COUNT:

  The number of internal iterations which have been required to commit epoch transactions. This value should be normally be slightly greater than or equal to the value of CONFLICT_TRANS_CONFLICT_COMMIT_COUNT. Ndb_conflict_trans_detect_iter_count shows this value for the default replication channel.

• CONFLICT_TRANS_CONFLICT_COMMIT_COUNT:

  The number of epoch transactions which have been committed after requiring transactional conflict handling. Ndb_conflict_trans_conflict_commit_count shows this value for the default replication channel.

• CONFLICT_EPOCH_DELETE_DELETE_COUNT:

  The number of delete-delete conflicts detected. A delete-delete conflict occurs when a delete operation is applied, but the row does not exist. Ndb_epoch_delete_delete_count shows this value for the default replication channel.

• CONFLICT_REFLECTED_OP_PREPARE_COUNT:

  The number of reflected operations which have been received and prepared for execution. Ndb_conflict_reflected_op_prepare_count shows this value for the default replication channel.

• CONFLICT_REFLECTED_OP_DISCARD_COUNT:

  The nmber of reflected operations which have not been applied due to errors during execution. Ndb_conflict_reflected_op_discard_count shows this value for the default replication channel.

• CONFLICT_REFRESH_OP_COUNT:

  The number of refresh operations which have been prepared. Ndb_conflict_refresh_op_count shows this value for the default replication channel.

• CONFLICT_LAST_CONFLICT_EPOCH:

  The most recent NDB epoch on this replica during which a conflict was detected. Ndb_conflict_last_conflict_epoch shows this value for the default replication channel.

• CONFLICT_LAST_STABLE_EPOCH:

  The most recent NDB epoch during which no conflicts were detected. Ndb_conflict_last_stable_epoch shows this value for the default replication channel.

For more information, see the descriptions of the indicated server status variables, as well as Section 25.7, “NDB Cluster Replication”.