22.3.2.5 NDB Cluster mysqld Option and Variable Reference

Com_show_ndb_status: Count of SHOW NDB STATUS statements

Handler_discover: Number of times that tables have been discovered

ndb-batch-size: Size (in bytes) to use for NDB transaction batches

ndb-blob-read-batch-bytes: Specifies size in bytes that large BLOB reads should be batched into. 0 = no limit.

ndb-blob-write-batch-bytes: Specifies size in bytes that large BLOB writes should be batched into. 0 = no limit.

ndb-cluster-connection-pool: Number of connections to the cluster used by MySQL

ndb-cluster-connection-pool-nodeids: Comma-separated list of node IDs for connections to the cluster used by MySQL; the number of nodes in the list must be the same as the value set for --ndb-cluster-connection-pool

ndb-connectstring: Point to the management server that distributes the cluster configuration

ndb-default-column-format: Use this value (FIXED or DYNAMIC) by default for COLUMN_FORMAT and ROW_FORMAT options when creating or adding columns to a table.

ndb-deferred-constraints: Specifies that constraint checks on unique indexes (where these are supported) should be deferred until commit time. Not normally needed or used; for testing purposes only.

ndb-distribution: Default distribution for new tables in NDBCLUSTER (KEYHASH or LINHASH, default is KEYHASH)

ndb-log-apply-status: Cause a MySQL server acting as a slave to log mysql.ndb_apply_status updates received from its immediate master in its own binary log, using its own server ID. Effective only if the server is started with the --ndbcluster option.

ndb-log-empty-epochs: When enabled, causes epochs in which there were no changes to be written to the ndb_apply_status and ndb_binlog_index tables, even when --log-slave-updates is enabled.

ndb-log-empty-update: When enabled, causes updates that produced no changes to be written to the ndb_apply_status and ndb_binlog_index tables, even when --log-slave-updates is enabled.

ndb-log-exclusive-reads: Log primary key reads with exclusive locks; allow conflict resolution based on read conflicts

ndb-log-orig: Log originating server id and epoch in mysql.ndb_binlog_index table

ndb-log-transaction-id: Write NDB transaction IDs in the binary log.

ndb-log-update-as-write: Toggles logging of updates on the master between updates (OFF) and writes (ON)

ndb-mgmd-host: Set the host (and port, if desired) for connecting to management server

ndb-nodeid: NDB Cluster node ID for this MySQL server

ndb-recv-thread-activation-threshold: Activation threshold when receive thread takes over the polling of the cluster connection (measured in concurrently active threads)

ndb-recv-thread-cpu-mask: CPU mask for locking receiver threads to specific CPUs; specified as hexadecimal. See documentation for details.

ndb-transid-mysql-connection-map: Enable or disable the ndb_transid_mysql_connection_map plugin; that is, enable or disable the INFORMATION_SCHEMA table having that name

ndb-wait-connected: Time (in seconds) for the MySQL server to wait for connection to cluster management and data nodes before accepting MySQL client connections

ndb-wait-setup: Time (in seconds) for the MySQL server to wait for NDB engine setup to complete

ndb-allow-copying-alter-table: Set to OFF to keep ALTER TABLE from using copying operations on NDB tables

Ndb_api_bytes_received_count: Amount of data (in bytes) received from the data nodes by this MySQL Server (SQL node)

Ndb_api_bytes_received_count_session: Amount of data (in bytes) received from the data nodes in this client session

Ndb_api_bytes_received_count_slave: Amount of data (in bytes) received from the data nodes by this slave

Ndb_api_bytes_sent_count: Amount of data (in bytes) sent to the data nodes by this MySQL Server (SQL node)

Ndb_api_bytes_sent_count_session: Amount of data (in bytes) sent to the data nodes in this client session

Ndb_api_bytes_sent_count_slave: Amount of data (in bytes) sent to the data nodes by this slave

Ndb_api_event_bytes_count: Number of bytes of events received by this MySQL Server (SQL node)

Ndb_api_event_bytes_count_injector: Number of bytes of events received by the NDB binary log injector thread

Ndb_api_event_data_count: Number of row change events received by this MySQL Server (SQL node)

Ndb_api_event_data_count_injector: Number of row change events received by the NDB binary log injector thread

Ndb_api_event_nondata_count: Number of events received, other than row change events, by this MySQL Server (SQL node)

Ndb_api_event_nondata_count_injector: Number of events received, other than row change events, by the NDB binary log injector thread

Ndb_api_pk_op_count: Number of operations based on or using primary keys by this MySQL Server (SQL node)

Ndb_api_pk_op_count_session: Number of operations based on or using primary keys in this client session

Ndb_api_pk_op_count_slave: Number of operations based on or using primary keys by this slave

Ndb_api_pruned_scan_count: Number of scans that have been pruned to a single partition by this MySQL Server (SQL node)

Ndb_api_pruned_scan_count_session: Number of scans that have been pruned to a single partition in this client session

Ndb_api_pruned_scan_count_slave: Number of scans that have been pruned to a single partition by this slave

Ndb_api_range_scan_count: Number of range scans that have been started by this MySQL Server (SQL node)

Ndb_api_range_scan_count_session: Number of range scans that have been started in this client session

Ndb_api_range_scan_count_slave: Number of range scans that have been started by this slave

Ndb_api_read_row_count: Total number of rows that have been read by this MySQL Server (SQL node)

Ndb_api_read_row_count_session: Total number of rows that have been read in this client session

Ndb_api_read_row_count_slave: Total number of rows that have been read by this slave

Ndb_api_scan_batch_count: Number of batches of rows received by this MySQL Server (SQL node)

Ndb_api_scan_batch_count_session: Number of batches of rows received in this client session

Ndb_api_scan_batch_count_slave: Number of batches of rows received by this slave

Ndb_api_table_scan_count: Number of table scans that have been started, including scans of internal tables, by this MySQL Server (SQL node)

Ndb_api_table_scan_count_session: Number of table scans that have been started, including scans of internal tables, in this client session

Ndb_api_table_scan_count_slave: Number of table scans that have been started, including scans of internal tables, by this slave

Ndb_api_trans_abort_count: Number of transactions aborted by this MySQL Server (SQL node)

Ndb_api_trans_abort_count_session: Number of transactions aborted in this client session

Ndb_api_trans_abort_count_slave: Number of transactions aborted by this slave

Ndb_api_trans_close_count: Number of transactions aborted (may be greater than the sum of TransCommitCount and TransAbortCount) by this MySQL Server (SQL node)

Ndb_api_trans_close_count_session: Number of transactions aborted (may be greater than the sum of TransCommitCount and TransAbortCount) in this client session

Ndb_api_trans_close_count_slave: Number of transactions aborted (may be greater than the sum of TransCommitCount and TransAbortCount) by this slave

Ndb_api_trans_commit_count: Number of transactions committed by this MySQL Server (SQL node)

Ndb_api_trans_commit_count_session: Number of transactions committed in this client session

Ndb_api_trans_commit_count_slave: Number of transactions committed by this slave

Ndb_api_trans_local_read_row_count: Total number of rows that have been read by this MySQL Server (SQL node)

Ndb_api_trans_local_read_row_count_session: Total number of rows that have been read in this client session

Ndb_api_trans_local_read_row_count_slave: Total number of rows that have been read by this slave

Ndb_api_trans_start_count: Number of transactions started by this MySQL Server (SQL node)

Ndb_api_trans_start_count_session: Number of transactions started in this client session

Ndb_api_trans_start_count_slave: Number of transactions started by this slave

Ndb_api_uk_op_count: Number of operations based on or using unique keys by this MySQL Server (SQL node)

Ndb_api_uk_op_count_session: Number of operations based on or using unique keys in this client session

Ndb_api_uk_op_count_slave: Number of operations based on or using unique keys by this slave

Ndb_api_wait_exec_complete_count: Number of times thread has been blocked while waiting for execution of an operation to complete by this MySQL Server (SQL node)

Ndb_api_wait_exec_complete_count_session: Number of times thread has been blocked while waiting for execution of an operation to complete in this client session

Ndb_api_wait_exec_complete_count_slave: Number of times thread has been blocked while waiting for execution of an operation to complete by this slave

Ndb_api_wait_meta_request_count: Number of times thread has been blocked waiting for a metadata-based signal by this MySQL Server (SQL node)

Ndb_api_wait_meta_request_count_session: Number of times thread has been blocked waiting for a metadata-based signal in this client session

Ndb_api_wait_meta_request_count_slave: Number of times thread has been blocked waiting for a metadata-based signal by this slave

Ndb_api_wait_nanos_count: Total time (in nanoseconds) spent waiting for some type of signal from the data nodes by this MySQL Server (SQL node)

Ndb_api_wait_nanos_count_session: Total time (in nanoseconds) spent waiting for some type of signal from the data nodes in this client session

Ndb_api_wait_nanos_count_slave: Total time (in nanoseconds) spent waiting for some type of signal from the data nodes by this slave

Ndb_api_wait_scan_result_count: Number of times thread has been blocked while waiting for a scan-based signal by this MySQL Server (SQL node)

Ndb_api_wait_scan_result_count_session: Number of times thread has been blocked while waiting for a scan-based signal in this client session

Ndb_api_wait_scan_result_count_slave: Number of times thread has been blocked while waiting for a scan-based signal by this slave

ndb_autoincrement_prefetch_sz: NDB auto-increment prefetch size

ndb_cache_check_time: Number of milliseconds between checks of cluster SQL nodes made by the MySQL query cache

ndb_clear_apply_status: Causes RESET SLAVE to clear all rows from the ndb_apply_status table; ON by default

Ndb_cluster_node_id: If the server is acting as an NDB Cluster node, then the value of this variable its node ID in the cluster

Ndb_config_from_host: The host name or IP address of the Cluster management server Formerly Ndb_connected_host

Ndb_config_from_port: The port for connecting to Cluster management server. Formerly Ndb_connected_port

Ndb_conflict_fn_epoch: Number of rows that have been found in conflict by the NDB$EPOCH() conflict detection function

Ndb_conflict_fn_epoch2: Number of rows that have been found in conflict by the NDB$EPOCH2() conflict detection function

Ndb_conflict_fn_epoch2_trans: Number of rows that have been found in conflict by the NDB$EPOCH2_TRANS() conflict detection function

Ndb_conflict_fn_epoch_trans: Number of rows that have been found in conflict by the NDB$EPOCH_TRANS() conflict detection function

Ndb_conflict_fn_max: If the server is part of an NDB Cluster involved in cluster replication, the value of this variable indicates the number of times that conflict resolution based on "greater timestamp wins" has been applied

Ndb_conflict_fn_old: If the server is part of an NDB Cluster involved in cluster replication, the value of this variable indicates the number of times that "same timestamp wins" conflict resolution has been applied

Ndb_conflict_last_conflict_epoch: Most recent NDB epoch on this slave in which a conflict was detected

Ndb_conflict_last_stable_epoch: Number of rows found to be in conflict by a transactional conflict function

Ndb_conflict_reflected_op_discard_count: Number of reflected operations that were not applied due an error during execution

Ndb_conflict_reflected_op_prepare_count: Number of reflected operations received that have been prepared for execution

Ndb_conflict_refresh_op_count: Number of refresh operations that have been prepared

Ndb_conflict_trans_conflict_commit_count: Number of epoch transactions committed after requiring transactional conflict handling

Ndb_conflict_trans_detect_iter_count: Number of internal iterations required to commit an epoch transaction. Should be (slightly) greater than or equal to Ndb_conflict_trans_conflict_commit_count

Ndb_conflict_trans_reject_count: Number of transactions rejected after being found in conflict by a transactional conflict function

Ndb_conflict_trans_row_conflict_count: Number of rows found in conflict by a transactional conflict function. Includes any rows included in or dependent on conflicting transactions.

Ndb_conflict_trans_row_reject_count: Total number of rows realigned after being found in conflict by a transactional conflict function. Includes Ndb_conflict_trans_row_conflict_count and any rows included in or dependent on conflicting transactions.

ndb_data_node_neighbour: Specifies cluster data node "closest" to this MySQL Server, for transaction hinting and fully replicated tables

ndb_default_column_format: Sets default row format and column format (FIXED or DYNAMIC) used for new NDB tables

ndb_deferred_constraints: Specifies that constraint checks should be deferred (where these are supported). Not normally needed or used; for testing purposes only.

ndb_distribution: Default distribution for new tables in NDBCLUSTER (KEYHASH or LINHASH, default is KEYHASH)

Ndb_conflict_delete_delete_count: Number of delete-delete conflicts detected (delete operation is applied, but row does not exist)

ndb_eventbuffer_free_percent: Percentage of free memory that should be available in event buffer before resumption of buffering, after reaching limit set by ndb_eventbuffer_max_alloc

ndb_eventbuffer_max_alloc: Maximum memory that can be allocated for buffering events by the NDB API. Defaults to 0 (no limit).

Ndb_execute_count: Provides the number of round trips to the NDB kernel made by operations

ndb_extra_logging: Controls logging of NDB Cluster schema, connection, and data distribution events in the MySQL error log

ndb_force_send: Forces sending of buffers to NDB immediately, without waiting for other threads

ndb_fully_replicated: Whether new NDB tables are fully replicated

ndb_index_stat_enable: Use NDB index statistics in query optimization

ndb_index_stat_option: Comma-separated list of tunable options for NDB index statistics; the list should contain no spaces

ndb_join_pushdown: Enables pushing down of joins to data nodes

ndb_log_apply_status: Whether or not a MySQL server acting as a slave logs mysql.ndb_apply_status updates received from its immediate master in its own binary log, using its own server ID

ndb_log_bin: Write updates to NDB tables in the binary log. Effective only if binary logging is enabled with --log-bin.

ndb_log_binlog_index: Insert mapping between epochs and binary log positions into the ndb_binlog_index table. Defaults to ON. Effective only if binary logging is enabled on the server.

ndb_log_empty_epochs: When enabled, epochs in which there were no changes are written to the ndb_apply_status and ndb_binlog_index tables, even when log_slave_updates is enabled

ndb_log_empty_update: When enabled, updates which produce no changes are written to the ndb_apply_status and ndb_binlog_index tables, even when log_slave_updates is enabled

ndb_log_exclusive_reads: Log primary key reads with exclusive locks; allow conflict resolution based on read conflicts

ndb_log_orig: Whether the id and epoch of the originating server are recorded in the mysql.ndb_binlog_index table. Set using the --ndb-log-orig option when starting mysqld.

ndb_log_transaction_id: Whether NDB transaction IDs are written into the binary log (Read-only.)

ndb-log-update-minimal: Log updates in a minimal format.

ndb_log_updated_only: Log complete rows (ON) or updates only (OFF)

ndb_metadata_check: Enable auto-detection of NDB metadata changes to synchronize with data dictionary

ndb_metadata_check_interval: Interval in seconds to perform check for NDB metadata changes to synchronize with data dictionary

Ndb_metadata_detected_count: Number of times NDB metadata change monitor thread has detected changes

Ndb_number_of_data_nodes: If the server is part of an NDB Cluster, the value of this variable is the number of data nodes in the cluster

ndb-optimization-delay: Sets the number of milliseconds to wait between processing sets of rows by OPTIMIZE TABLE on NDB tables

ndb_optimized_node_selection: Determines how an SQL node chooses a cluster data node to use as transaction coordinator

Ndb_pruned_scan_count: Number of scans executed by NDB since the cluster was last started where partition pruning could be used

Ndb_pushed_queries_defined: Number of joins that API nodes have attempted to push down to the data nodes

Ndb_pushed_queries_dropped: Number of joins that API nodes have tried to push down, but failed

Ndb_pushed_queries_executed: Number of joins successfully pushed down and executed on the data nodes

Ndb_pushed_reads: Number of reads executed on the data nodes by pushed-down joins

ndb_read_backup: Enable read from any replica

ndb_recv_thread_activation_threshold: Activation threshold when receive thread takes over the polling of the cluster connection (measured in concurrently active threads)

ndb_recv_thread_cpu_mask: CPU mask for locking receiver threads to specific CPUs; specified as hexadecimal. See documentation for details.

ndb_report_thresh_binlog_epoch_slip: NDB 7.5.4 and later: Threshold for number of epochs completely buffered, but not yet consumed by binlog injector thread which when exceeded generates BUFFERED_EPOCHS_OVER_THRESHOLD event buffer status message; prior to NDB 7.5.4: Threshold for number of epochs to lag behind before reporting binary log status

ndb_report_thresh_binlog_mem_usage: This is a threshold on the percentage of free memory remaining before reporting binary log status

ndb_row_checksum: When enabled, set row checksums; enabled by default

Ndb_scan_count: The total number of scans executed by NDB since the cluster was last started

ndb_show_foreign_key_mock_tables: Show the mock tables used to support foreign_key_checks=0

ndb_slave_conflict_role: Role for slave to play in conflict detection and resolution. Value is one of PRIMARY, SECONDARY, PASS, or NONE (default). Can be changed only when slave SQL thread is stopped. See documentation for further information.

Ndb_slave_max_replicated_epoch: The most recently committed NDB epoch on this slave. When this value is greater than or equal to Ndb_conflict_last_conflict_epoch, no conflicts have yet been detected.

Ndb_system_name: Configured cluster system name; empty if server not connected to NDB

ndb_table_no_logging: NDB tables created when this setting is enabled are not checkpointed to disk (although table schema files are created). The setting in effect when the table is created with or altered to use NDBCLUSTER persists for the lifetime of the table.

ndb_table_temporary: NDB tables are not persistent on disk: no schema files are created and the tables are not logged

ndb_use_exact_count: Use exact row count when planning queries

ndb_use_transactions: Forces NDB to use a count of records during SELECT COUNT(*) query planning to speed up this type of query

ndb_version: Shows build and NDB engine version as an integer

ndb_version_string: Shows build information including NDB engine version in ndb-x.y.z format

ndbcluster: Enable NDB Cluster (if this version of MySQL supports it) Disabled by --skip-ndbcluster

ndbinfo_database: The name used for the NDB information database; read only

ndbinfo_max_bytes: Used for debugging only

ndbinfo_max_rows: Used for debugging only

ndbinfo_offline: Put the ndbinfo database into offline mode, in which no rows are returned from tables or views

ndbinfo_show_hidden: Whether to show ndbinfo internal base tables in the mysql client. The default is OFF.

ndbinfo_table_prefix: The prefix to use for naming ndbinfo internal base tables

ndbinfo_version: The version of the ndbinfo engine; read only

server-id-bits: Sets the number of least significant bits in the server_id actually used for identifying the server, permitting NDB API applications to store application data in the most significant bits. server_id must be less than 2 to the power of this value.

slave_allow_batching: Turns update batching on and off for a replication slave

transaction_allow_batching: Allows batching of statements within a transaction. Disable AUTOCOMMIT to use.