Comprehensive list of system variables to configure Spider globally or per session, affecting connection timeouts, buffering, and query pushdown strategies.
The following variables are available when the Spider storage engine has been installed.
See Server System Variables for a complete list of system variables and instructions on setting them.
See also the Full list of MariaDB options, system and status variables.
MariaDB starting with
Starting from , MariaDB 10.6.15, , , MariaDB 10.11.5, , all spider system variables with the value -1 for deferring to table parameter values follow the correct overriding mechanism: table parameter (if set) overrides system variables (if not -1) overrides actual variable default. As a side effect, all such system variables in all versions have the same default value as the table param default value. Before this change, a non-minus-one system variable value would override the table parameter value. That is, if both the system variable value and the table parameter value were set to be non-minus-one, the system variable value would prevail. For + where the system variable default values were the same as table param default instead of -1, this means that if the system variable were not set, but a table param is set to a non-default value, the default would override the non-default value.
spider_auto_increment_modeDescription: The mode.
-1 Falls back to the default value, if the is not set.
0 Normal Mode. Uses a counter that Spider gets from the remote backend server with an exclusive lock for the auto-increment value. This mode is slow. Use Quick Mode (2), if you use Spider tables with the table partitioning feature and the auto-increment column is the first column of the index.
spider_bgs_first_readDescription: Number of first read records to use when performing a concurrent background search. To start a range scan on the remote backend, the storage engine first needs to send the first record. Fetching a second record in the same query can save a network round trip stopping the plan if the backend has a single record. The first and second reads are used to warm up for background search. When not using and , the third read fetches the remaining data source in a single fetch.
-1 Falls back to the default value, if the is not set.
0 Records are usually retrieved.
spider_bgs_modeDescription: Background search mode. This enables the use of a thread per data server connection if the query is not shard-based and must be distributed across shards. The partitioning plugin scans partitions one after the other to optimize memory usage. Because the shards are external, reading all shards can be performed in parallel when the plan prunes multiple partitions.
-1 Falls back to the default value, if the is not set.
0 Disables background search.
spider_bgs_second_readDescription: Number of second read records on the backend server when using background search. When the first records are found from , the engine continues scanning a range adding a LIMIT of and .
-1 Falls back to the default value, if the is not set.
0 Records are usually retrieved.
spider_bka_engineDescription: Storage engine used with temporary tables when the system variable is set to 1. Defaults to the value of the , which is by default.
Scope: Global, Session
Dynamic: Yes
Data Type: string
spider_bka_modeDescription: Internal action to perform when multi-split reads are disabled. If the system variable is set to 0, Spider uses this variable to determine how to handle statements when the optimizer resolves range retrieval to multiple conditions.
-1 Falls back to the default value, if the is not set.
0 Uses "union all".
spider_bka_table_name_typeDescription: The type of temporary table name for bka.
Scope: Global, Session
Dynamic: Yes
Data Type: numeric
spider_block_sizeDescription: Size of memory block used in MariaDB. Can usually be left unchanged.
Scope: Global, Session
Dynamic: Yes
Data Type: numeric
spider_buffer_sizeDescription: Buffer size. -1, the default, will use the .
Scope: Global, Session
Dynamic: Yes
Data Type: numeric
spider_bulk_sizeDescription: Size in bytes of the buffer when multiple grouping multiple INSERT statements in a batch, (that is, bulk inserts).
-1 The is adopted.
0 or greater: Size of the buffer.
spider_bulk_update_modeDescription: Bulk update and delete mode. Note: If you use a non-default value for the or system variables, Spider sets this variable to 2.
-1 Falls back to the default value, if the is not set.
0 Sends UPDATE
spider_bulk_update_sizeDescription: Size in bytes for UPDATE and DELETE queries when generating bulk updates.
-1 The is adopted.
0 or greater: Size of buffer.
spider_casual_readDescription: Casual Reads enables all isolation levels, (such as repeatable reads) to work with transactions on multiple backends. With auto-commit queries, you can relax read consistency and run on multiple connections to the backends. This enables parallel queries across partitions, even if multiple shards are stored on the same physical server. Deprecated in due to the complexity of the code for little benefit.
-1 Use .
0 Use casual read.
spider_conn_recycle_modeDescription: Connection recycle mode.
0 Disconnect.
1 Recycle by all sessions.
spider_conn_recycle_strictDescription: Whether to force the creation of new connections.
1 Don't force.
0 Force new connection
spider_conn_wait_timeoutDescription: Max waiting time in seconds for Spider to get a remote connection.
Scope: Global
Dynamic: Yes
Data Type: numeric
spider_connect_error_intervalDescription: Return same error code until interval passes if connection is failed
Scope: Global,
Dynamic: Yes
Data Type: numeric
spider_connect_mutexDescription: Whether to serialize remote servers connections (use mutex at connecting). Use this parameter if you get an error or slowdown due to too many connection processes.
0 Not serialized.
1 : Serialized.
spider_connect_retry_countDescription: Number of times to retry connections that fail due to too many connection processes.
Scope: Global, Session
Dynamic: Yes
Data Type: numeric
spider_connect_retry_intervalDescription: Interval in microseconds for connection failure due to too many connection processes.
Scope: Global, Session
Dynamic: Yes
Data Type: numeric
spider_connect_timeoutDescription: Timeout in seconds to declare remote backend unresponsive when opening a connection. Change for high-latency networks.
-1 The is adopted.
0 Less than 1.
spider_crd_bg_modeDescription: Indexes cardinality statistics in the background. Disable when the system variable is set to 3 or when the variable is set to 0.
-1 Falls back to the default value, if the is not set.
0
spider_crd_intervalDescription: Time interval in seconds of index cardinality statistics. Set to 0 to always get the latest information from remote servers.
-1 The is adopted.
1 or more: Interval in seconds table state confirmation.
spider_crd_modeDescription: Mode for index cardinality statistics. By default, uses SHOW at the table-level.
-1,0 Uses the .
1 Uses the SHOW command.
spider_crd_syncDescription: Synchronize index cardinality statistics in partitioned tables.
-1 Falls back to the default value, if the is not set.
0 Disables synchronization.
spider_crd_typeDescription: Type of cardinality calculation. Only effective when the system variable is set to use SHOW (1) or to use the Information Schema (2).
-1 Falls back to the default value, if the is not set.
spider_crd_weightDescription: Weight coefficient used to calculate effectiveness of index from the cardinality of column. For more information, see the description for the system variable.
-1 Falls back to the default value, if the is not set.
0 or greater: Weight.
spider_delete_all_rows_typeDescription: The type of delete_all_rows.
Scope: Global, Session
Dynamic: Yes
Data Type: numeric
spider_direct_dup_insertDescription: Manages duplicate key check for , and to remote servers. This can save on network roundtrips if the key always maps to a single partition. For bulk operations, records are checked for duplicate key errors one by one on the remote server, unless you set it to avoid duplicate checks on local servers (1).
-1 Falls back to the default value, if the is not set.
0
spider_direct_order_limitDescription: Pushes ORDER BY and LIMIT operations to the remote server.
-1 Falls back to the default value, if the is not set.
0 Uses local execution.
spider_disable_group_by_handlerDescription: Whether to disable the spider group by handler, which if created takes over the query execution after query optimization is done.
OFF Does not disable the spider group by handler.
ON Disables the spider group by handler.
spider_dry_accessDescription: Simulates an empty result-set. No queries are sent to the backend. Use for performance tuning.
0 Normal access.
1 All access from Spider to data node is suppressed.
spider_error_read_modeDescription: Sends an empty result-set when reading a backend server raises an error. Useful with applications that don't implement transaction replays.
-1 Falls back to the default value, if the is not set.
0 Returns an error.
spider_error_write_modeDescription: Sends an empty result-set when writing to a backend server raises an error. Useful with applications that don't implement transaction replays.
-1 Falls back to the default value, if the is not set.
0 Returns an error.
spider_first_readDescription: Number of first read records to start a range scan on the backend server. Spider needs to send the first record. Fetching the second record saves network round-trips, stopping the plan if the backend has a single record. First read and second read are used to warm up for background searches, third reads without using the and system variables fetches the remaining data source in a single last fetch.
-1 Use the .
0 Usually retrieves records.
spider_force_commitDescription: Behavior when error occurs on XA PREPARE, XA COMMIT, and XA ROLLBACK statements.
0 Returns the error.
1
spider_general_logDescription: Whether Spider logs all commands to the General Log. Spider logs error codes according to the system variable.
OFF Logs no commands.
ON Logs commands to the General Log.
spider_ignore_commentsDescription: Whether to unconditionally ignore COMMENT and CONNECTION strings without checking whether table options are specified.
Scope: Global, Session
Dynamic: Yes
Data Type: boolean
spider_index_hint_pushdownDescription: Whether to use pushdown index hints, like force_index.
0 Do not use pushdown hints
1 Use pushdown hints
spider_init_sql_alloc_sizeDescription: Initial size of the local SQL buffer.
-1 Falls back to the default value, if the is not set.
0 or greater: Size of the buffer.
spider_internal_limitDescription: Limits the number of records when acquired from a remote server.
-1 The is adopted.
0 or greater: Records limit.
spider_internal_offsetDescription: Skip records when acquired from the remote server.
-1 Falls back to the default value, if the is not set.
0 or more : Number of records to skip.
spider_internal_optimizeDescription: Whether to perform push down operations for statements.
-1 Falls back to the default value, if the is not set.
0 Transmitted.
spider_internal_optimize_localDescription: Whether to transmit to remote servers when statements are executed on the local server.
-1 Falls back to the default value, if the is not set.
0 Not transmitted.
spider_internal_sql_log_offDescription: Whether to log SQL statements sent to the remote server in the .
Explicitly setting this system variable to either ON or OFF causes the Spider node to send a SET sql_log_off statement to each of the data nodes using the SUPER privilege.
spider_internal_unlockDescription: Whether to transmit unlock tables to the connection of the table used with SELECT statements.
0 Not transmitted.
1 Transmitted.
spider_internal_xaDescription: Whether to implement XA at the server- or storage engine-level. When using the server-level, set different values for the system variable on all server instances to generate different xid values.
OFF Uses the storage engine protocol.
ON Uses the server protocol.
spider_internal_xa_id_typeDescription: The type of internal_xa id.
Scope: Global, Session
Dynamic: Yes
Data Type: numeric
spider_internal_xa_snapshotDescription: Limitation for reading consistent data on all backend servers when using MariaDB's internal XA implementation and START TRANSACTION WITH CONSISTENT SNAPSHOT.
0 Raise error when using a Spider table.
1 Raise error when issued a START TRANSACTION statement.
spider_load_crd_at_startupDescription: Whether to load CRD from the system table at startup.
-1 Use
0 Do not load
spider_load_sts_at_startupDescription: Whether to load STS from the system table at startup.
-1 Use
0 Do not load
spider_local_lock_tableDescription: Whether to push statements down to the remote server.
0 Transmitted.
1 Not transmitted.
spider_lock_exchangeDescription: Whether to convert and statements into a statement.
0 Not converted.
1 Converted.
spider_log_result_error_with_sqlDescription: How to log SQL statements with result errors.
0 No log
1 Log error
spider_log_result_errorsDescription: Log results from data nodes to the Spider node in the . Performs no logging by default.
0 : Logs no errors from data nodes.
1 : Logs errors from data nodes.
spider_low_mem_readDescription: Whether to use low memory mode when executing queries issued internally to remote servers that return result-sets.
-1 Falls back to the default value, if the is not set.
0 Doesn't use low memory mode.
spider_max_connectionsDescription: Maximum number of connections from Spider to a remote MariaDB servers. Defaults to 0, which is no limit.
Command-line: --spider-max-connections
Scope: Global
Dynamic: Yes
spider_max_orderDescription: Maximum number of columns for ORDER BY operations.
-1 The is adopted.
0 and greater: Maximum number of columns.
spider_multi_split_readDescription: Whether to divide a statement into multiple SQL statements sent to the remote backend server when the optimizer resolves range retrievals to multiple conditions.
-1 Falls back to the default value, if the is not set.
0 Doesn't divide statements.
spider_net_read_timeoutDescription: TCP timeout in seconds to declare remote backend servers unresponsive when reading from a connection. Change for high latency networks.
-1 Falls back to the default value, if the is not set.
0 Less than 1 second timeout.
spider_net_write_timeoutDescription: TCP timeout in seconds to declare remote backend servers unresponsive when writing to a connection. Change for high latency networks.
-1 The is adopted.
0 Less than 1 second timeout.
spider_ping_interval_at_trx_startDescription: Resets the connection with keepalive timeout in seconds by sending a ping.
0 At every transaction.
1 and greater: Number of seconds.
spider_quick_modeDescription: Sets the backend query buffering to cache on the remote backend server or in the local buffer.
-1 Falls back to the default value, if the is not set.
0 Local buffering, it acquires records collectively with store_result.
spider_quick_page_byteDescription: Memory limit by size in bytes in a page when acquired record by record.
-1 The is used. When quick_mode is 1 or 2, Spider stores at least 1 record even if quick_page_byte is smaller than 1 record. When quick_mode is 3, quick_page_byte is used for judging using temporary tables. That is given priority when spider_quick_page_byte is set.
0 or greater: Memory limit.
spider_quick_page_sizeDescription: Number of records in a page when acquired record by record.
-1 The is adopted.
0 or greater: Number of records.
spider_read_only_modeDescription: Whether to allow writes on Spider tables.
-1 Falls back to the default value, if the is not set.
0 Allows writes to Spider tables.
spider_remote_access_charsetDescription: Forces the specified session when connecting to the backend server. This can improve connection time performance.
Scope: Global, Session
Dynamic: Yes
Data Type: string
spider_remote_autocommitDescription: Sets the auto-commit mode when connecting to backend servers. This can improve connection time performance.
-1 Doesn't change the auto-commit mode.
0 Sets the auto-commit mode to 0.
spider_remote_default_databaseDescription: Sets the local default database when connecting to backend servers. This can improve connection time performance.
Scope: Global, Session
Dynamic: Yes
Data Type: string
spider_remote_sql_log_offDescription: Sets the system variable to use when connecting to backend servers.
-1 Doesn't set the value.
0 Doesn't log Spider SQL statements to remote backend servers.
spider_remote_time_zoneDescription: Forces the specified setting when connecting to backend servers. This can improve connection performance when you know the time zone.
Scope: Global
Dynamic: Yes
Data Type: string
spider_remote_trx_isolationDescription: Sets the when connecting to the backend server.
-1 Doesn't set the Isolation Level.
0 Sets to the READ UNCOMMITTED level.
spider_remote_wait_timeoutDescription: Wait timeout in seconds on remote server. -1 means not set.
Scope: Global, Session
Dynamic: Yes
Data Type: numeric
spider_reset_sql_allocDescription: Resets the per connection SQL buffer after an SQL statement executes.
-1 Falls back to the default value, if the is not set.
0 Doesn't reset.
spider_same_server_linkDescription: Enables the linking of a table to the same local instance.
0 Disables linking.
1 Enables linking.
spider_second_readDescription: Number of second read records on the backend server when the first records are found from the first read. Spider continues scanning a range, adding a LIMIT using the and variables.
-1 Falls back to the default value, if the is not set.
0 Usually retrieves records.
spider_select_column_modeDescription: Mode for column retrieval from remote backend server.
-1 Falls back to the default value, if the is not set.
0 Uses index columns when the SELECT statement can resolve with an index, otherwise uses all columns.
spider_selupd_lock_modeDescription: Local lock mode on INSERT SELECT.
-1 Falls back to the default value, if the is not set.
0 Takes no locks.
spider_semi_split_readDescription: Whether to use chunk retrieval with offset and limit parameters on SQL statements sent to the remote backend server when using the system variable.
-1 Falls back to the default value, if the is not set.
0 Doesn't use chunk retrieval.
spider_semi_split_read_limitDescription: Sets the limit value for the system variable.
-1 Falls back to the default value, if the is not set.
0 or more: The limit value.
spider_semi_table_lockDescription: Enables semi-table locking. This adds a statement to SQL executions sent to the remote backend server when using non-transactional storage engines to preserve consistency between roundtrips.
0 Disables semi-table locking.
1 Enables semi-table locking.
spider_semi_table_lock_connectionDescription: Whether to use multiple connections with semi-table locking. To enable semi-table locking, use the system variable.
-1 Falls back to the default value, if the is not set.
0 Uses the same connection.
spider_semi_trxDescription: Enables semi-transactions. This controls transaction consistency when an SQL statement is split into multiple statements issued to the backend servers. You can preserve or relax consistency as need. Spider encapsulates auto-committed SQL statements within a transaction on the remote backend server. When using READ COMMITTED or READ UNCOMMITTED to force consistency, set the system variable to 2.
0 Disables semi-transaction consistency.
spider_semi_trx_isolationDescription: Set consistency during range SQL execution when is 1
-1 OFF
0 READ UNCOMMITTED
spider_skip_default_conditionDescription: Whether to compute condition push downs.
-1 Falls back to the default value, if the is not set.
0 Computes condition push downs.
spider_skip_parallel_searchDescription: Whether to skip parallel search by specific conditions.
-1 :use
0 :not skip
spider_slave_trx_isolationDescription: Transaction isolation level when Spider table is used by slave SQL thread.
-1 off
0 read uncommitted
spider_split_readDescription: Number of records in chunk to retry the result when a range query is sent to remote backend servers.
-1 Falls back to the default value, if the is not set.
0 or more: Number of records.
spider_store_last_crdDescription: Whether to store last CRD result in the system table.
-1 Use .
0 Do not store last CRD result in the system table.
spider_store_last_stsDescription: Whether to store last STS result in the system table.
-1 Use .
0 Do not store last STS result in the system table.
spider_strict_group_byDescription: Whether to use columns in select clause strictly for group by clause
-1 Use the .
0 Do not strictly use columns in select clause for group by clause
spider_sts_bg_modeDescription:
Enables background confirmation for table statistics. When background confirmation is enabled, Spider uses one thread per partition to maintain table status. Disable when the system variable is set to 0, which causes Spider to always retrieve the latest information as need. It is effective, when the system variable is set to 10.
-1 Falls back to the default value, if the is not set.
spider_sts_intervalDescription: Time interval of table statistics from the remote backend servers.
-1 Falls back to the default value, if the is not set.
0 Retrieves the latest table statistics on request.
spider_sts_modeDescription: Table statistics mode. Mode for table statistics. The command is used at the table level default.
-1,0 Uses the .
1 Uses the SHOW command.
spider_sts_syncDescription: Synchronizes table statistics in partitioned tables.
-1 Falls back to the default value, if the is not set.
0 Doesn't synchronize table statistics in partitioned tables.
spider_support_xaDescription: XA Protocol for mirroring and for multi-shard transactions.
1 Enables XA Protocol for these Spider operations.
0 Disables XA Protocol for these Spider operations.
spider_suppress_comment_ignored_warningDescription: Whether to suppress warnings that table COMMENT or CONNECTION strings are ignored due to specified table options.
Scope: Global, Session
Dynamic: Yes
Data Type: boolean
spider_sync_autocommitDescription: Whether to push down local auto-commits to remote backend servers.
OFF Pushes down local auto-commits.
ON Doesn't push down local auto-commits.
spider_sync_sql_modeDescription: Whether to sync .
OFF No sync
ON Sync
spider_sync_time_zoneDescription: Whether to push the local time zone down to remote backend servers.
OFF Doesn't synchronize time zones.
ON Synchronize time zones.
spider_sync_trx_isolationDescription: Pushes local transaction isolation levels down to remote backend servers.
OFF Doesn't push down local isolation levels.
ON Pushes down local isolation levels.
spider_table_crd_thread_countDescription: Static background thread count of table crd.
Command line: --spider-table-crd-thread-count=#
Scope: Global
Dynamic: No
spider_table_init_error_intervalDescription: Interval in seconds where the same error code is returned if table initialization fails. Use to protect against infinite loops in table links.
Scope: Global
Dynamic: Yes
Data Type: numeric
spider_table_sts_thread_countDescription: Static background thread count of table sts.
Command line: --spider-table-sts-thread-count=#
Scope: Global
Dynamic: No
spider_udf_ct_bulk_insert_intervalDescription: Interval in milliseconds between bulk inserts at copying. For use with the UDF spider_copy_tables, which copies table data linked to a Spider table from the source server to destination server using bulk insert. If this interval is 0, it may cause higher write traffic.
-1 Uses the UDF parameter.
0 and more: Time in milliseconds.
spider_udf_ct_bulk_insert_rowsDescription: Number of rows to insert at a time when copying during bulk inserts.
-1, 0: Uses the .
1 and more: Number of rows
spider_udf_ds_bulk_insert_rowsDescription: Number of rows inserted at a time during bulk inserts when the result-set is stored in a temporary table on executing a UDF.
-1, 0 Uses the UDF parameter.
1 or more: Number of rows
spider_udf_ds_table_loop_modeDescription: Whether to store the result-set in the same temporary table when the temporary table list count for UDF is less than the result-set count on UDF execution.
-1 Falls back to the default value, if the is not set.
0 Drops records.
spider_udf_ds_use_real_tableDescription: Whether to use real table for temporary table list.
-1 Use UDF parameter.
0 Do not use real table.
spider_udf_table_lock_mutex_countDescription: Mutex count of table lock for Spider UDFs.
Scope: Global
Dynamic: No
Data Type: numeric
spider_udf_table_mon_mutex_countDescription: Mutex count of table mon for Spider UDFs.
Scope: Global
Dynamic: No
Data Type: numeric
spider_use_all_conns_snapshotDescription: Whether to pass START TRANSACTION WITH SNAPSHOT statements to all connections.
OFF Doesn't pass statement to all connections.
ON Passes statement to all connections.
spider_use_cond_other_than_pk_for_updateDescription: Whether to use all conditions even if condition has a primary key.
0 Don't use all conditions
1 Use all conditions
spider_use_consistent_snapshotDescription:
Whether to push a local START TRANSACTION WITH CONSISTENT statement down to remote backend servers.
OFF Doesn't push the local statement down.
ON Pushes the local statement down.
spider_use_default_databaseDescription: Whether to use the default database.
OFF Doesn't use the default database.
ON Uses the default database.
spider_use_flash_logsDescription: Whether to push statements down to remote backend servers.
OFF Doesn't push the statement down.
ON Pushes the statement down.
spider_use_handlerDescription: Converts SQL statements.
When the system variable is set to 0, Spider disables conversions to prevent use of the statement on the isolation level.
-1 Falls back to the default value, if the is not set.
0 Converts statements into
spider_use_pushdown_udfDescription:
When using a UDF function in a condition and the system variable is set to 1, whether to execute the UDF function locally or push it down.
-1 Falls back to the default value, if the is not set.
0 Doesn't transmit the UDF
spider_use_snapshot_with_flush_tablesDescription:
Whether to encapsulate and statements when START TRANSACTION WITH CONSISTENT and FLUSH TABLE WITH READ LOCK statements are sent to the remote backend servers.
0 : No encapsulation.
1 : Encapsulates, only when the
spider_use_table_charsetDescription: Whether to use the local table for the remote backend server connections.
-1 Falls back to the default value, if the is not set.
0 Use utf8.
spider_versionDescription: The current Spider version. Removed in when the Spider version number was matched with the server version.
Scope: Global
Dynamic: No
Data Type: string
spider_wait_timeoutDescription: Wait timeout in seconds of setting to remote server. -1 means not set.
Scope: Global, Session
Dynamic: Yes
Data Type: numeric
spider_xa_register_modeDescription: Mode of XA transaction register into system table.
0 Register all XA transactions
1 Register only write XA transactions
This page is licensed: CC BY-SA / Gnu FDL
1 Quick Mode. Uses an internal Spider counter for the auto-increment value. This mode is fast, but it is possible for duplicates to occur when updating the same table from multiple Spider proxies.
2 Set Zero Mode. The auto-increment value is given by the remote backend. Sets the column to 0, even if you set the value to the auto-increment column in your statement. If you use the table with the table partitioning feature, it sets to zero after choosing an inserted partition.
3 When the auto-increment column is set to NULL, the value is given by the remote backend server. If you set the auto-increment column to 0,the value is given by the local server. Set spider_reset_auto_increment to 2 or 3 if you want to use an auto-increment column on the remote server.
Scope: Global, Session
Dynamic: Yes
Data Type: numeric
Default Session Value: 0
Default Table Value: 0
Range: -1 to 3
DSN Parameter Name: aim
1 and greater: Number of records.
Scope: Global, Session
Dynamic: Yes
Data Type: numeric
Default Session Value: 2
Default Table Value: 2
Range: -1 to 9223372036854775807
DSN Parameter Name: bfr
1 Uses background search when searching without locks
2 Uses background search when searching without locks or with shared locks.
3 Uses background search regardless of locks.
Scope: Global, Session
Dynamic: Yes
Data Type: numeric
Default Session Value: 0
Default Table Value: 0
Range: -1 to 3
DSN Parameter Name: bmd
1 and greater: Number of records.
Scope: Global, Session
Dynamic: Yes
Default Session Value: 100
Default Table Value: 100
Range: -1 to 9223372036854775807
DSN Parameter Name: bsr
Default Session Value: ""
Default Table Value: Memory
DSN Parameter Name: bke
1 Uses a temporary table, if it is judged acceptable.
2 Uses a temporary table, if it is judged acceptable and avoids replication delay.
Scope: Global, Session
Dynamic: Yes
Data Type: numeric
Default Session Value: 1
Default Table Value: 1
Range: -1 to 2
DSN Parameter Name: bkm
Default Session Value: 1
Range: -1 to 1
Default Session Value: 16384
Range: 0 to 4294967295
DSN Parameter Name: bsz
Default Session Value: 16000
Default Table Value: 16000
Range: -1 to 2147483647
Introduced:
Scope: Global, Session
Dynamic: Yes
Data Type: numeric
Default Session Value: 16000
Default Table Value: 16000
Range: -1 to 2147483647
DSN Parameter Name: bsz
DELETE1 Collects multiple UPDATE and DELETE statements, then sends the collected statements one by one.
2 Collects multiple UPDATE and DELETE statements and sends them together.
Scope: Global, Session
Dynamic: Yes
Data Type: numeric
Default Session Value: 0
Default Table Value: 0
Range: -1 to 2
DSN Parameter Name: bum
Scope: Global, Session
Dynamic: Yes
Data Type: numeric
Default Session Value: 16000
Default Table Value: 16000
Range: -1 to 2147483647
DSN Parameter Name: bus
1 Choose connection channel automatically.
2 to 63 Number of connection channels.
Scope: Global, Session
Dynamic: Yes
Data Type: numeric
Default Session Value: 0
Default Table Value: 0
Range: -1 to 63
DSN Parameter Name: ##
Deprecated:
2Scope: Global, Session
Dynamic: Yes
Data Type: numeric
Range: 0 to 2
Default Session Value: 0
Dynamic: Yes
Data Type: numeric
Default Session Value: 0
Range: 0 to 1
Default Session Value: 10
Range: 0 to 1000
Introduced:
Default Value: 1
Range: 0 to 4294967295
Dynamic: Yes
Data Type: boolean
Default Session Value: 0
Default Session Value: 2 (>= MariaDB 11.8), 1000 (<= )
Range: 0 to 2147483647
Default Session Value: 1000
Range: -1 to 9223372036854775807
1 and greater: Number of seconds.Scope: Global, Session
Dynamic: Yes
Data Type: numeric
Default Session Value: 6
Default Table Value: 0
Range: -1 to 2147483647
DSN Parameter Name: cto
2 Enables background confirmation.
Scope: Global, Session
Dynamic: Yes
Data Type: numeric
Default Session Value: 2
Default Table Value: 1
Range: -1 to 2
DSN Parameter Name: cbm
Scope: Global, Session
Dynamic: Yes
Data Type: numeric
Default Session Value: 51
Default Table Value: 51
Range: -1 to 2147483647
DSN Parameter Name: civ
2 Uses the Information Schema.
3 Uses the EXPLAIN command.
Scope: Global, Session
Dynamic: Yes
Data Type: numeric
Default Session Value: 1
Default Table Value: 1
Range: -1 to 3
DSN Parameter Name: cmd
Deprecated: ,
1 Uses table state synchronization when opening a table, but afterwards performs no synchronization.2 Enables synchronization.
Scope: Global, Session
Dynamic: Yes
Data Type: numeric
Default Session Value: 0
Default Table Value: 0
Range: -1 to 2
DSN Parameter Name: csy
01 Uses the value of the spider_crd_weight system variable, as an addition value.
2 Uses the value of the spider_crd_weight system variable, as a multiplication value.
Scope: Global, Session
Dynamic: Yes
Data Type: numeric
Default Session Value: 2
Default Table Value: 2
Range: -1 to 2
DSN Parameter Name: ctp
Deprecated: ,
Scope: Global, Session
Dynamic: Yes
Data Type: numeric
Default Session Value: 2
Default Table Value: 2
Range: -1 to 2147483647
DSN Parameter Name: cwg
Deprecated: ,
Default Session Value: 1
Range: -1 to 1
1 Avoids duplicate checks on the local server.
Scope: Global, Session
Dynamic: Yes
Data Type: numeric
Default Session Value: 0
Default Table Value: 0
Range: -1 to 1
DSN Parameter Name: ddi
1 Uses push down execution.
Scope: Global, Session
Dynamic: Yes
Data Type: numeric
Default Session Value: 2
Default Table Value: 9223372036854775807
Range: -1 to 9223372036854775807
DSN Parameter Name: dol
Dynamic: Yes
Data Type: boolean
Default Value: OFF
Introduced:
Dynamic: No
Data Type: boolean
Default Value: OFF
1 Returns an empty result.Scope: Global, Session
Dynamic: Yes
Data Type: numeric
Default Session Value: 0
Default Table Value: 0
Range: -1 to 1
DSN Parameter Name: erm
1 Returns an empty result-set on error.Scope: Global, Session
Dynamic: Yes
Data Type: numeric
Default Session Value: 0
Default Table Value: 0
Range: -1 to 1
DSN Parameter Name: ewm
1 and greater: Sets the number of first read records.
Scope: Global, Session
Dynamic: Yes
Data Type: numeric
Default Session Value: 0
Default Table Value: 2
Range: -1 to 9223372036854775807
DSN Parameter Name: frd
xid2 Continues processing the XA transaction, disregarding all errors.
Scope: Global, Session
Dynamic: Yes
Data Type: numeric
Default Session Value: 0
Range: 0 to 2
Dynamic: Yes
Data Type: boolean
Default Session Value: OFF
Default Value: OFF
Introduced:
Scope: Global, Session
Dynamic: Yes
Data Type: boolean
Default Session Value: OFF
Introduced:
Dynamic: Yes
Data Type: numeric
Default Session Value: 1024
Default Table Value: 1024
DSN Parameter Name: isa
Range: -1 to 2147483647
Deprecated: , ,
Dynamic: Yes
Data Type: numeric
Default Session Value: 9223372036854775807
Default Table Value: 9223372036854775807
Range: -1 to 9223372036854775807
DSN Parameter Name: ilm
Deprecated: ,
Dynamic: Yes
Data Type: numeric
Default Session Value: 0
Default Table Value: 0
Range: -1 to 9223372036854775807
DSN Parameter Name: ios
Deprecated: ,
1 Not transmitted.Scope: Global, Session
Dynamic: Yes
Data Type: numeric
Default Session Value: 0
Default Table Value: 0
Range: -1 to 1
DSN Parameter Name: iom
1 Transmitted.Default Session Value: 0
Default Table Value: 0
Range: -1 to 1
DSN Parameter Name: iol
-1 Don't know or does not matter; don't send 'SET SQL_LOG_OFF' statement0 Send 'SET SQL_LOG_OFF 0' statement to data nodes (logs SQL statements to the remote server)
1 Send 'SET SQL_LOG_OFF 1' statement to data nodes (doesn't log SQL statements to the remote server)
Scope: Global, Session
Dynamic: Yes
Data Type: numeric (previously boolean)
Range: -1 to 1
Default Session Value: -1 (previously ON)
Data Type: boolean
Default Session Value: 0
Scope: Global, Session
Dynamic: Yes
Data Type: boolean
Default Session Value: OFF
Default Session Value: 0
Range: -1 to 1
2 Takes a consistent snapshot on each backend, but loses global consistency.
3 Starts transactions with XA, but removes CONSISTENT SNAPSHOT.
Scope: Global, Session
Dynamic: Yes
Data Type: numeric
Range: 0 to 3
Default Session Value: 0
1 LoadScope: Global
Dynamic: Yes
Data Type: numeric
Default Session Value: 1
Range: -1 to 1
Introduced:
Deprecated: ,
1 LoadScope: Global
Dynamic: Yes
Data Type: boolean
Default Session Value: 1
Range: -1 to 1
Introduced:
Deprecated: ,
Dynamic: Yes
Data Type: boolean
Default Value: 0
Dynamic: Yes
Data Type: boolean
Default Value: 0
23 Log warning
4 Log info (Added in )
Scope: Global
Dynamic: Yes
Data Type: numeric
Default Value: 0
Range: 0 to 4
2 : Logs errors from data nodes, as well as warning summaries.3 : Logs errors from data nodes, as well as warning summaries and details.
4 : Logs errors from data nodes, as well as warning summaries and details, and result summaries.
Scope: Global
Dynamic: Yes
Data Type: numeric
Default Value: 0
Range: 0 to 4
1 Uses low memory mode.Data Type: numeric
Default Session Value: 1
Default Table Value: 1
Range: -1 to 1
Data Type: numeric
Default Session Value: 0
Range: 0 to 99999
Introduced:
Scope: Global, Session
Dynamic: Yes
Data Type: numeric
Default Session Value: 32767
Default Table Value: 32767
Range: -1 to 32767
DSN Parameter Name: mod
1 Divides statements.
Scope: Global, Session
Dynamic: Yes
Data Type: numeric
Default Session Value: 100
Default Table Value: 100
Range: -1 to 2147483647
DSN Parameter Name: msr
1 and greater: Timeout in seconds.Scope: Global, Session
Dynamic: Yes
Data Type: numeric
Default Session Value: 600
Default Table Value: 600
Range: -1 to 2147483647
DSN Parameter Name: nrt
1 and more: Timeout in seconds.Scope: Global, Session
Dynamic: Yes
Data Type: numeric
Default Session Value: 600
Default Table Value: 600
Range: -1 to 2147483647
DSN Parameter Name: nwt
Dynamic: Yes
Data Type: numeric
Default Value: 3600
Range: 0 to 2147483647
1 Remote buffering, it acquires records one by one. Interrupts don't wait and recovery on context switch back.
2 Remote buffering, it acquires records one by one. Interrupts wait to the end of the acquisition.
3 Local buffering, uses a temporary table on disk when the result-set is greater than the value of the spider_quick_page_size system variable.
Scope: Global, Session
Dynamic: Yes
Data Type: numeric
Default Session Value: 3
Default Table Value: 3
Range: -1 to 3
DSN Parameter Name: qmd
Scope: Global, Session
Dynamic: Yes
Data Type: numeric
Default Session Value: 10485760
Range: -1 to 9223372036854775807
Introduced: ,
Dynamic: Yes
Data Type: numeric
Default Session Value: 1024 (>=), -1 (<= MariaDB 10.6)
Default Table Value: 100
Range: -1 to 9223372036854775807
DSN Parameter Name: qps
1 Makes tables read- only.Scope: Global, Session
Dynamic: Yes
Data Type: numeric
Default Session Value: 0 (>=), -1 (<= MariaDB 10.6)
Default Table Value: 0
Range: -1 to 1
DSN Parameter Name: rom
Default Session Value: null
1 Sets the auto-commit mode to 1.
Scope: Global
Dynamic: Yes
Data Type: numeric
Default Session Value: -1
Range: -1 to 1
Default Session Value: Empty string
1 Logs SQL statements on remote backendScope: Global
Dynamic: Yes
Data Type: numeric
Default Session Value: -1
Range: -1 to 1
Default Session Value: null
1 Sets to the READ COMMITTED level.
2 Sets to the REPEATABLE READ level.
3 Sets to the SERIALIZABLE level.
Scope: Global
Dynamic: Yes
Data Type: numeric
Default Session Value: -1
Range: -1 to 3
Default Value: -1
Range: -1 to 2147483647
Introduced:
1 Resets.Scope: Global, Session
Dynamic: Yes
Data Type: numeric
Default Session Value: 1
Default Table Value: 1
Range: -1 to 1
DSN Parameter Name: rsa
Dynamic: Yes
Data Type: boolean
Default Session Value: OFF
1 and greater: Number of records.
Scope: Global, Session
Dynamic: Yes
Default Session Value: 0
Default Table Value: 0
Range: -1 to 9223372036854775807
DSN Parameter Name: srd
1 Uses all columns judged necessary to resolve the query.
Scope: Global, Session
Dynamic: Yes
Data Type: numeric
Default Session Value: 1
Default Table Value: 1
Range: -1 to 1
DSN Parameter Name: scm
1 Takes shared locks.
2 Takes exclusive locks.
Scope: Global, Session
Dynamic: Yes
Data Type: numeric
Default Session Value: 1
Default Table Value: 1
Range: -1 to 2
DSN Parameter Name: slm#
1 or more Uses chunk retrieval.
Scope: Global, Session
Dynamic: Yes
Data Type: numeric
Default Session Value: 2
Default Table Value: 2
Range: -1 to 2147483647
DSN Parameter Name: ssr#
Dynamic: Yes
Data Type: numeric
Default Session Value: 9223372036854775807
Default Table Value: 9223372036854775807
Range: -1 to 9223372036854775807
DSN Parameter Name: ssl#
Scope: Global, Session
Dynamic: Yes
Data Type: numeric
Default Session Value: 0 (>=), 1 (<= )
Range: 0 to 1
DSN Parameter Name: stl#
1 Uses different connections.
Scope: Global, Session
Dynamic: Yes
Data Type: numeric
Default Session Value: 1
Default Table Value: 1
Range: -1 to 1
DSN Parameter Name: stc#
1 Enables semi-transaction consistency.
Scope: Global, Session
Dynamic: Yes
Data Type: boolean
Default Session Value: ON
1 READ COMMITTED2 REPEATABLE READ
3 SERIALIZABLE
Scope: Global, Session
Dynamic: Yes
Data Type: numeric
Default Session Value: -1
Range: -1 to 3
1 Doesn't compute condition push downs.Scope: Global, Session
Dynamic: Yes
Data Type: numeric
Default Session Value: 0
Default Table Value: 0
Range: -1 to 1
DSN Parameter Name: sdc
1 :skip parallel search if query is not SELECT statement2 :skip parallel search if query has SQL_NO_CACHE
3 :1+2
Command line: --spider-skip-parallel-search=#
Scope: Global, Session
Dynamic: Yes
Data Type: numeric
Default Session Value: 0
Range: -1 to 3
Introduced:
1 read committed2 repeatable read
3 serializable
Command line: --spider-slave-trx-isolation=#
Scope: Global
Dynamic: Yes
Data Type: numeric
Default Session Value: -1
Range: -1 to 3
Introduced: ,
Dynamic: Yes
Data Type: numeric
Default Session Value: 9223372036854775807
Default Table Value: 9223372036854775807
Range: -1 to 9223372036854775807
DSN Parameter Name: srd
1 Store last CRD result in the system table.Command line: --spider-store-last-crd=#
Scope: Global
Dynamic: Yes
Data Type: numeric
Default Session Value: 1
Range: -1 to 1
Introduced:
Deprecated: ,
1 Store last STS result in the system table.Command line: --spider-store-last-sts=#
Scope: Global
Dynamic: Yes
Data Type: numeric
Default Session Value: 1
Range: -1 to 1
Introduced:
Deprecated: ,
1 Use columns in select clause strictly for group by clauseScope: Global, Session
Dynamic: Yes
Data Type: numeric
Default Session Value: 1
Range: -1 to 1
Introduced:
0 Disables background confirmation.1 Enables background confirmation (create thread per table/partition).
2 Enables background confirmation (use static threads). (from MariaDB 10.)
Scope: Global, Session
Dynamic: Yes
Data Type: numeric
Default Session Value: 2
Range: -1 to 2
DSN Parameter Name: sbm
1 or more: Interval in seconds for table state confirmation.Scope: Global, Session
Dynamic: Yes
Data Type: numeric
Default Session Value: 10
Default Table Value: 10
Range: -1 to 2147483647
DSN Parameter Name: siv
2 Uses the Information Schema.
Scope: Global, Session
Dynamic: Yes
Data Type: numeric
Default Session Value: 1
Default Table Value: 1
Range: -1 to 2
DSN Parameter Name: smd
Deprecated: ,
1 Synchronizes table state when opening a table, doesn't synchronize after opening.2 Synchronizes table statistics.
Scope: Global, Session
Dynamic: Yes
Data Type: numeric
Default Session Value: 0
Default Table Value: 0
Range: -1 to 2
DSN Parameter Name: ssy
Dynamic: No
Data Type: boolean
Default Table Value: 1
Default Value: OFF
Introduced:
Dynamic: Yes
Data Type: boolean
Default Session Value: ON
Dynamic: Yes
Data Type: boolean
Default Value: ON
Introduced:
Dynamic: Yes
Data Type: boolean
Default Session Value: OFF
Removed:
Dynamic: Yes
Data Type: boolean
Default Session Value: ON
Data Type: numeric
Default Value:
1 (>= , , MariaDB 10.6.17, MariaDB 10.11.7, , , )
10 (<= , , MariaDB 10.6.16, MariaDB 10.11.6, , , )
Range: 1 to 4294967295
Deprecated:
Default Value: 1
Range: 0 to 4294967295
Data Type: numeric
1 (>= , , MariaDB 10.6.17, MariaDB 10.11.7, , , )
10 (<= , , MariaDB 10.6.16, MariaDB 10.11.6, , , )
Range: 1 to 4294967295
Deprecated:
Scope: Global
Dynamic: Yes
Data Type: numeric
Default Value: 10
Default Table Value: 10
Range: -1 to 2147483647
Deprecated: ,
Removed:
Dynamic: Yes
Data Type: numeric
Default Value: 100
Default Table Value: 100
Range: -1 to 9223372036854775807
Deprecated: ,
Removed:
Dynamic: Yes
Data Type: numeric
Default Value: 3000
Default Table Value: 3000
Range: -1 to 9223372036854775807
Deprecated: ,
Removed:
1 Inserts the last table.
2 Inserts the first table and loops again.
Scope: Global, Session
Dynamic: Yes
Data Type: numeric
Default Value: 0
Range: -1 to 2
Deprecated: ,
Removed:
1 Use real table.Scope: Global, Session
Dynamic: Yes
Data Type: numeric
Default Value: 0
Range: -1 to 1
Deprecated: ,
Removed:
Default Value: 20
Range: 1 to 4294967295
Removed:
Default Value: 20
Range: 1 to 4294967295
Removed:
Scope: Global, Session
Dynamic: Yes
Data Type: boolean
Default Session Value: OFF
Dynamic: Yes
Data Type: numeric
Default Value: 1
Range: 0 to 1
Introduced: ,
Scope: Global, Session
Dynamic: Yes
Data Type: boolean
Default Value: OFF
Dynamic: Yes
Data Type: boolean
Default Value: ON
Dynamic: Yes
Data Type: boolean
Default Value: OFF
1 Passes HANDLER to the remote backend server.
2 Converts SQL statements to HANDLER statements.
Scope: Global, Session
Dynamic: Yes
Data Type: numeric
Default Value: 0
Default Table Value: 0
Range: -1 to 3
DSN Parameter Name: uhd
Deprecated: ,
Removed:
1 Transmits the UDF.
Scope: Global, Session
Dynamic: Yes
Data Type: numeric
Default Value: -1
Default Table Value: 1
Range: -1 to 1
DSN Parameter Name: upu
1.2 :
Synchronizes the snapshot using a LOCK TABLES statement and [flush|FLUSH TABLES]] at the XA transaction level. This is only effective when the spider_use_all_cons_snapshot system variable is set to 1.
Scope: Global, Session
Dynamic: Yes
Data Type: numeric
Default Value: 0
Range: 0 to 2
1 Uses the table character set.
Scope: Global, Session
Dynamic: Yes
Data Type: numeric
Default Value: 1
Default Table Value: 1
Range: -1 to 1
DSN Parameter Name: utc
Removed:
Default Value: 604800
Range: -1 to 2147483647
Introduced:
--spider-xa-register-mode=#Scope: Global, Session
Dynamic: Yes
Data Type: numeric
Default Value: 1
Range: 0 to 1
Introduced:
Deprecated: ,