18.3.4.1 MySQL Cluster mysqld Option and Variable Reference

The following table provides a list of the command-line options, server and status variables applicable within mysqld when it is running as an SQL node in a MySQL Cluster. For a table showing all command-line options, server and status variables available for use with mysqld, see Section 5.1.1, “Server Option and Variable Reference”.

Table 18.9 MySQL Cluster mysqld Options and Variables: MySQL Cluster NDB 7.2

Option or Variable NameCommand LineSystem VariableScope
Option FileStatus VariableDynamic
Notes

Handler_discover

NNBoth
NYN

The number of times that tables have been discovered

Ndb_api_wait_exec_complete_count_session

NNSession
NYN

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

NNGlobal
NYN

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

Ndb_api_wait_exec_complete_count

NNGlobal
NYN

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_scan_result_count_session

NNSession
NYN

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

NNGlobal
NYN

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

Ndb_api_wait_scan_result_count

NNGlobal
NYN

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

Ndb_api_wait_meta_request_count_session

NNSession
NYN

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

Ndb_api_wait_meta_request_count_slave

NNGlobal
NYN

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

Ndb_api_wait_meta_request_count

NNGlobal
NYN

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

Ndb_api_wait_nanos_count_session

NNSession
NYN

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

NNGlobal
NYN

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

Ndb_api_wait_nanos_count

NNGlobal
NYN

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

Ndb_api_bytes_sent_count_session

NNSession
NYN

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

Ndb_api_bytes_sent_count_slave

NNGlobal
NYN

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

Ndb_api_bytes_sent_count

NNGlobal
NYN

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

Ndb_api_bytes_received_count_session

NNSession
NYN

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

Ndb_api_bytes_received_count_slave

NNGlobal
NYN

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

Ndb_api_bytes_received_count

NNGlobal
NYN

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

Ndb_api_trans_start_count_session

NNSession
NYN

Number of transactions started in this client session.

Ndb_api_trans_start_count_slave

NNGlobal
NYN

Number of transactions started by this slave.

Ndb_api_trans_start_count

NNGlobal
NYN

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

Ndb_api_trans_commit_count_session

NNSession
NYN

Number of transactions committed in this client session.

Ndb_api_trans_commit_count_slave

NNGlobal
NYN

Number of transactions committed by this slave.

Ndb_api_trans_commit_count

NNGlobal
NYN

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

Ndb_api_trans_abort_count_session

NNSession
NYN

Number of transactions aborted in this client session.

Ndb_api_trans_abort_count_slave

NNGlobal
NYN

Number of transactions aborted by this slave.

Ndb_api_trans_abort_count

NNGlobal
NYN

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

Ndb_api_trans_close_count_session

NNSession
NYN

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

Ndb_api_trans_close_count_slave

NNGlobal
NYN

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

Ndb_api_trans_close_count

NNGlobal
NYN

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

Ndb_api_pk_op_count_session

NNSession
NYN

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

Ndb_api_pk_op_count_slave

NNGlobal
NYN

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

Ndb_api_pk_op_count

NNGlobal
NYN

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

Ndb_api_uk_op_count_session

NNSession
NYN

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

Ndb_api_uk_op_count_slave

NNGlobal
NYN

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

Ndb_api_uk_op_count

NNGlobal
NYN

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

Ndb_api_table_scan_count_session

NNSession
NYN

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

Ndb_api_table_scan_count_slave

NNGlobal
NYN

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

Ndb_api_table_scan_count

NNGlobal
NYN

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

Ndb_api_range_scan_count_session

NNSession
NYN

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

Ndb_api_range_scan_count_slave

NNGlobal
NYN

Number of range scans that have been started by this slave.

Ndb_api_range_scan_count

NNGlobal
NYN

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

Ndb_api_pruned_scan_count_session

NNSession
NYN

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

Ndb_api_pruned_scan_count_slave

NNGlobal
NYN

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

Ndb_api_pruned_scan_count

NNGlobal
NYN

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

Ndb_api_scan_batch_count_session

NNSession
NYN

Number of batches of rows received in this client session.

Ndb_api_scan_batch_count_slave

NNGlobal
NYN

Number of batches of rows received by this slave.

Ndb_api_scan_batch_count

NNGlobal
NYN

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

Ndb_api_read_row_count_session

NNSession
NYN

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

Ndb_api_read_row_count_slave

NNGlobal
NYN

Total number of rows that have been read by this slave.

Ndb_api_read_row_count

NNGlobal
NYN

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

Ndb_api_trans_local_read_row_count_session

NNSession
NYN

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

Ndb_api_trans_local_read_row_count_slave

NNGlobal
NYN

Total number of rows that have been read by this slave.

Ndb_api_trans_local_read_row_count

NNGlobal
NYN

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

Ndb_api_event_data_count_injector

NNGlobal
NYN

Number of row change events received by the NDB binlog injector thread.

Ndb_api_event_data_count

NNGlobal
NYN

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

Ndb_api_event_nondata_count_injector

NNGlobal
NYN

Number of events received, other than row change events, by the NDB binlog injector thread.

Ndb_api_event_nondata_count

NNGlobal
NYN

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

Ndb_api_event_bytes_count_injector

NNGlobal
NYN

Number of bytes of events received by the NDB binlog injector thread.

Ndb_api_event_bytes_count

NNGlobal
NYN

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

Ndb_number_of_data_nodes

NNGlobal
NYN

If the server is part of a MySQL Cluster, the value of this variable is the number of data nodes in the cluster

Ndb_conflict_fn_max

NNGlobal
NYN

If the server is part of a MySQL 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

NNGlobal
NYN

If the server is part of a MySQL 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_fn_epoch

NNGlobal
NYN

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

Ndb_conflict_fn_epoch_trans

NNGlobal
NYN

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

Ndb_conflict_trans_row_conflict_count

NNGlobal
NYN

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

Ndb_conflict_trans_row_reject_count

NNGlobal
NYN

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_conflict_trans_reject_count

NNGlobal
NYN

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

Ndb_conflict_trans_detect_iter_count

NNGlobal
NYN

The 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_conflict_commit_count

NNGlobal
NYN

The number of epoch transactions committed after requiring transactional conflict handling.

ndb_optimization_delay

NYGlobal
NNY

Sets the number of milliseconds to wait between processing sets of rows by OPTIMIZE TABLE on NDB tables.

ndb_table_temporary

NYSession
NNY

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

ndb_table_no_logging

NYSession
NNY

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_autoincrement_prefetch_sz

YYBoth
YNY

NDB auto-increment prefetch size

ndb-batch-size

YYGlobal
YNN

The size (in bytes) to use for NDB transaction batches

ndb-blob-read-batch-bytes

YYBoth
YNY

Specifies the size in bytes that large BLOB reads should be batched into. 0 = no limit.

ndb-blob-write-batch-bytes

YYBoth
YNY

Specifies the size in bytes that large BLOB writes should be batched into. 0 = no limit.

ndb_cache_check_time

YYGlobal
YNY

The number of milliseconds between checks of cluster SQL nodes made by the MySQL query cache

ndb-cluster-connection-pool

YYGlobal
YYN

The number of connections to the cluster used by MySQL

ndb_join_pushdown

NYGlobal
NNN

Enables pushing down of joins to data nodes

Ndb_execute_count

NNGlobal
NYN

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

Ndb_scan_count

NNGlobal
NYN

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

Ndb_pruned_scan_count

NNGlobal
NYN

The number of scans executed by NDB since the cluster was last started where partition pruning could be used

ndb-connectstring

YN 
YNN

Point to the management server that distributes the cluster configuration

ndb_extra_logging

YYGlobal
YNY

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

ndb_force_send

YYBoth
YNY

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

ndb_use_exact_count

NYBoth
NNY

Use exact row count when planning queries

ndb-log-apply-status

YYGlobal
YNN

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_bin

YYBoth
NNY

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

ndb_log_binlog_index

YYGlobal
NNY

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-orig

YYGlobal
YNN

Log originating server id and epoch in mysql.ndb_binlog_index table.

ndb-log-transaction-id

YYGlobal
YNN

Write NDB transaction IDs in the binary log. Requires --log-bin-v1-events=OFF.

ndb_log_transaction_id

NYGlobal
NNN

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

ndb_log_updated_only

YYGlobal
YNY

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

ndb-log-update-as-write

YYGlobal
YNY

Toggles logging of updates on the master between updates (OFF) and writes (ON)

ndb-log-empty-epochs

YYGlobal
YNY

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_epochs

YYGlobal
YNY

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-transid-mysql-connection-map

YN 
NNN

Enable or disable the ndb_transid_mysql_connection_map plugin; that is, enable or disable the INFORMATION_SCHEMA table having that name.

Ndb_pushed_reads

NNGlobal
NYN

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

Ndb_pushed_queries_defined

NNGlobal
NYN

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

Ndb_pushed_queries_dropped

NNGlobal
NYN

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

Ndb_pushed_queries_executed

NNGlobal
NYN

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

ndb-nodeid

YNGlobal
YYN

MySQL Cluster node ID for this MySQL server

ndb-mgmd-host

YN 
YNN

Set the host (and port, if desired) for connecting to the management server

ndb-wait-connected

YYGlobal
YNN

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

YYGlobal
YNN

Time (in seconds) for the MySQL server to wait for NDB engine setup to complete.

ndbcluster

YN 
YNN

Enable NDB Cluster (if this version of MySQL supports it)

ndbinfo_database

NYGlobal
NNN

The name used for the NDB information database; read only.

ndbinfo_max_bytes

YYBoth
NNY

Used for debugging only.

ndbinfo_max_rows

YYBoth
NNY

Used for debugging only.

ndbinfo_offline

NYGlobal
NNY

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

ndbinfo_show_hidden

YYBoth
NNY

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

ndbinfo_table_prefix

YYBoth
NNY

The prefix to use for naming ndbinfo internal base tables. Defaults to 'ndb$'.

ndbinfo_version

NYGlobal
NNN

The version of the ndbinfo engine; read only.

server-id-bits

YYGlobal
YNN

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.

transaction_allow_batching

NYSession
NNY

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

have_ndbcluster

NYGlobal
NNN

Whether mysqld supports NDB Cluster tables (set by --ndbcluster option)

ndb-deferred-constraints

YYBoth
YNY

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_deferred_constraints

YYBoth
YNY

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

ndb-distribution

YYGlobal
YNY

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

ndb_distribution

YYGlobal
YNY

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

ndb_index_stat_cache_entries

YN 
YNN

Sets the granularity of the statistics by determining the number of starting and ending keys

ndb_index_stat_enable

YN 
YNN

Use NDB index statistics in query optimization

ndb_index_stat_option

YN 
YNN

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

ndb_index_stat_update_freq

YN 
YNN

How often to query data nodes instead of the statistics cache

ndb_optimized_node_selection

YN 
YNN

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

ndb_report_thresh_binlog_epoch_slip

YN 
YNN

This is a threshold on the number of epochs to be behind before reporting binlog status

ndb_report_thresh_binlog_mem_usage

YN 
YNN

This is a threshold on the percentage of free memory remaining before reporting binlog status

ndb_use_transactions

YYBoth
YNY

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

Ndb_cluster_node_id

NNBoth
NYN

If the server is acting as a MySQL Cluster node, then the value of this variable its node ID in the cluster

Ndb_config_from_host

NNBoth
NYN

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

Ndb_config_from_port

NNBoth
NYN

The port for connecting to the Cluster management server. Formerly Ndb_connected_port

Com_show_ndb_status

NNBoth
NYN

Count of SHOW NDB STATUS statements