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”.

This table was added in NDB 9.0.0.