Spider Server System Variables

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.

spider_auto_increment_mode

• Description: The auto increment mode.
  • -1 The table parameter is adopted.
  • 0 Normal mode. Uses a counter that Spider gets from the remote backend server with an exclusive lock for the auto increment value. Slow. Switch to quick mode if you use Spider tables with the table partitioning feature and the auto increment column is the first column of the index.
  • 1 Quick mode. Uses an internal Spider counter for the auto increment value. Fast, but it is possible for duplicates to occur if you update the same table from multiple Spider proxies.
  • 2 Set zero value. Auto increment value is given by the remote backend. Sets zero value even if you set a value to the auto increment column. Sets zero value after choosing an inserted partition if you use a table with the table partitioning feature.
  • 3 If you set an auto increment column to a null value, the auto increment value is given by the remote backend server. If you set a zero value to the auto increment column, the auto increment value is given by the local server. Rather use spider_reset_auto_increment=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: -1
• Default Table Value: 0
• DSN Parameter Name: aim

spider_bgs_first_read

• Description: Number of first read records when concurrent background search is used. 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. First read and second read are used to warm up for background search, third read without using spider_split_read and spider_semi_split_read will fetch the remaining data source in a single last fetch.
  • -1 The table parameter is adopted.
  • 0 Records are usually retrieved.
  • 1 or more Number of records.
• Scope: Global, Session
• Dynamic: Yes
• Data Type: numeric
• Default Session Value: -1
• Default Table Value: 2
• DSN Parameter Name: bfr

spider_bgs_mode

• Description: Background search mode. Partitioning plugin scans partitions one after the other to optimize the memory usage. Because the shards are external, reading all shards can be performed in parallel when the plan prunes multiple partitions.
  • -1 The table parameter is adopted.
  • 0 Background search is disabled.
  • 1 Background search is used if search with no lock.
  • 2 Background search is used if search with no lock or shared lock.
  • 3 Background search is used regardless of the lock.
• Scope: Global, Session
• Dynamic: Yes
• Data Type: numeric
• Default Session Value: -1
• Default Table Value: 0
• DSN Parameter Name: bmd

spider_bgs_second_read

• Description: Number of second read records on the backend server when background search is used. When the first records are found from spider_bgs_first_read, the engine will continue scanning a range adding a LIMIT spider_bgs_first_read, spider_bgs_second_read.
  • -1 The table parameter is adopted.
  • 0 Records are usually retrieved.
  • 1 or more Number of records.
• Scope: Global, Session
• Dynamic: Yes
• Default Session Value: -1
• Default Table Value: 100
• DSN Parameter Name: bsr

spider_bka_engine

• Description: The temporary table storage engine used when the bka_mode table parameter is 1. The default is the value of the table parameter, memory by default.
• Scope: Global, Session
• Dynamic: Yes
• Data Type: string
• Default Session Value: ""
• Default Table Value: Memory
• DSN Parameter Name: bke

spider_bka_mode

• Description: The internal action for using multi_split_read=0.
  • -1 The table parameter is adopted.
  • 0 Use "union all".
  • 1 Use temporary table if it is judged acceptable.
  • 2 Same as 1 and avoiding replication delay.
• Scope: Global, Session
• Dynamic: Yes
• Data Type: numeric
• Default Session Value: -1
• Default Table Value: 1
• DSN Parameter Name: bkm

spider_block_size

• Description: Size of memory block used in MariaDB. Can usually be left unchanged.
• Scope: Global, Session
• Dynamic: Yes
• Data Type: numeric
• Default Session Value: 16384
• DSN Parameter Name: bsz

spider_bulk_access_free

• Description: Free mode of bulk access resources.
  • -1 The table parameter is adopted.
  • 0 in reset
  • 1 in close
• Data Type: numeric
• Default Session Value: -1
• Default Table Value: 0
• Introduced: Spider 3.0
• DSN Parameter Name: baf

spider_bulk_size

• Description: Size in bytes of the buffer when multiple INSERT's are grouped in a batch, bulk insert.
  • -1 The table parameter is adopted.
  • 0 or more: Size of the buffer.
• Scope: Global, Session
• Dynamic: Yes
• Data Type: numeric
• Default Session Value: -1
• Default Table Value: 16000
• DSN Parameter Name: bsz

spider_bulk_update_mode

• Description: Bulk update and delete mode. If spider_bgs_mode or spider_split_read are changed from their default settings, Spider treats this parameter setting as 2.
  • -1 The table parameter is adopted.
  • 0 Send "update" and "delete" statements one by one.
  • 1 Send collected multiple "update" and "delete" statements. Collected statements are sent one by one.
  • 2 Send collected multiple "update" and "delete" statements. Collected statements are sent together.
• Scope: Global, Session
• Dynamic: Yes
• Data Type: numeric
• Default Session Value: -1
• Default Table Value: 0
• DSN Parameter Name: bum

spider_bulk_update_size

• Description: Size in bytes of the "update" and "delete" query generated at bulk update.
  • -1 The table parameter is adopted.
  • 0 or more Size of buffer.
• Scope: Global, Session
• Dynamic: Yes
• Data Type: numeric
• Default Session Value: -1
• Default Table Value: 16000
• DSN Parameter Name: bus

spider_casual_read

• Description: The default for spider is to have casual read this can enable all isolation level like repeatable read to work for transactions on multiple backend. For auto commit queries read consistency can be relaxed and run on multiple connections to the backends.
  • -1 Use table parameter
  • 0 Casual read
  • 1 Choose connection channel automatically
  • 2-63 Number of connection channel
• Scope: Global, Session
• Dynamic: Yes
• Data Type: numeric
• Default Session Value: -1
• Default Table Value: 0
• DSN Parameter Name: ##

spider_conn_recycle_mode

• Description: Connection recycle mode.
  • 0 Disconnect.
  • 1 Recycles by all sessions.
  • 2 Recycles in the same session.
• Scope: Global, Session
• Dynamic: Yes
• Data Type: numeric
• Default Session Value: 0

spider_conn_recycle_strict

• Description: Whether or not to force the creation of a new connection.
  • ON Don't force.
  • OFF Force new connection
• Scope: Global, Session
• Dynamic: Yes
• Data Type: boolean
• Default Session Value: OFF

spider_connect_mutex

• Description: Serialized remote servers connections. You can use this parameter if you get an error or slowdown from too many connection processes.
  • 0 Not serialized.
  • 1 : Serialized.
• Scope: Global, Session
• Dynamic: Yes
• Data Type: numeric
• Default Session Value: 0

spider_connect_retry_count

• Description: Connect-retry-count for connection failure caused by too many connection processes.
• Scope: Global, Session
• Dynamic: Yes
• Data Type: numeric
• Default Session Value: 1000

spider_connect_retry_interval

• Description: Connect-retry-interval in micro-seconds for connection failure caused by too many connection processes.
• Scope: Global, Session
• Dynamic: Yes
• Data Type: numeric
• Default Session Value: 1000

spider_connect_timeout

• Description: The timeout in seconds to declare remote backend not responsive when opening a connection. Can be changed for high latency networks.
  • -1 The table parameter is adopted.
  • 0 Less then 1.
  • 1 and more Number of second.
• Scope: Global, Session
• Dynamic: Yes
• Data Type: numeric
• Max Value: 2147483647
• Default Session Value: -1
• Default Table Value: 0
• DSN Parameter Name: cto

spider_crd_bg_mode

• Description: Indexes the cardinality statistics in the background. Disable when crd_mode = 3 or crd_interval = 0
  • -1 The table parameter is adopted.
  • 0 Background confirmation is disabled.
  • 1 Background confirmation is enabled.
• Scope: Global, Session
• Dynamic: Yes
• Data Type: numeric
• Default Session Value: -1
• Default Table Value: 1
• DSN Parameter Name: cbm

spider_crd_interval

• Description: Time interval in seconds of index cardinality statistics. Set to 0 to always get the newest information from remote servers.
  • -1 The table parameter is adopted.
  • 1 or more Interval in seconds table state confirmation.
• Scope: Global, Session
• Dynamic: Yes
• Data Type: numeric
• Default Session Value: -1
• Default Table Value: 51
• DSN Parameter Name: civ

spider_crd_mode

• Description: Mode for index cardinality statistics. The show command is used at the table level default.
  • -1,0 The table parameter is adopted.
  • 1 The show command is used.
  • 2 The information schema is used.
  • 3 The explain command is used.
• Scope: Global, Session
• Dynamic: Yes
• Data Type: numeric
• Default Session Value: -1
• Default Table Value: 1
• DSN Parameter Name: cmd

spider_crd_sync

• Description: Index cardinality statistics synchronization in partitioned tables.
  • -1 The table parameter is adopted.
  • 0 No synchronization.
  • 1 Table state is synchronized when opening a table, no more synchronization later.
  • 2 Synchronization.
• Scope: Global, Session
• Dynamic: Yes
• Data Type: numeric
• Default Session Value: -1
• Default Table Value: 0
• DSN Parameter Name: csy

spider_crd_type

• Description: Type of cardinality calculation. Only effective when crd_mode is 1 or 2.
  • -1 The table parameter is adopted.
  • 0 crd_weight is used as a fixed value.
  • 1 crd_weight is used as an addition value.
  • 2 crd_weight is used as a multiplication value.
• Scope: Global, Session
• Dynamic: Yes
• Data Type: numeric
• Default Session Value: -1
• Default Table Value: 2
• DSN Parameter Name: ctp

spider_crd_weight

• Description: Weight coefficient to calculate effectiveness of index from cardinality of column. See spider_crd_type.
  • -1 The table parameter is adopted.
  • 0 or more Weight.
• Scope: Global, Session
• Dynamic: Yes
• Data Type: numeric
• Default Session Value: -1
• Default Table Value: 2
• DSN Parameter Name: cwg

spider_direct_dup_insert

• Description: How to manage duplicate key check REPLACE and INSERT IGNORE and LOAD DATA LOCAL INFILE to remote server. Can save on network roundtrips if the key always maps to a single partition. For bulk operations, records will be checked for duplicate errors one by one on the remote server unless you set to spider_direct_dup_insert=1.
  • -1 The table parameter is adopted.
  • 0 Duplicate check on local server.
  • 1 Avoid duplicate check on local server.
• Scope: Global, Session
• Dynamic: Yes
• Data Type: numeric
• Default Session Value: -1
• Default Table Value: 0
• DSN Parameter Name: ddi

spider_direct_order_limit

• Description: Push down ORDER BY and LIMIT to remote server
  • -1 The table parameter is adopted.
  • 0 Local execution
  • 1 Push down execution
• Scope: Global, Session
• Dynamic: Yes
• Data Type: numeric
• Default Session Value: -1
• Default Table Value: 0
• DSN Parameter Name: dol

spider_error_read_mode

• Description: Can send empty result when error raised reading from backend server. Can be useful for applications that do not implement replaying transactions.
  • -1 use table parameter
  • 0return error
  • 1return empty record on error
• Scope: Global, Session
• Dynamic: Yes
• Data Type: numeric
• Default Session Value: -1
• Default Table Value: 0
• DSN Parameter Name: erm

spider_error_write_mode

• Description: Can send empty result when error raised writing to backend server. Can be useful for applications that do not implement replaying transactions.
  • -1 :use table parameter
  • 0 :return error
  • 1 :return empty record on error
• Scope: Global, Session
• Dynamic: Yes
• Data Type: numeric
• Default Session Value: -1
• Default Table Value: 0
• DSN Parameter Name: ewm

spider_first_read

• Description: Number of first read records to start a range scan on the backend server. The storage engine first needs to send the first record. Fetching the second record can save a network round trip stopping the plan if the backend has a single record. First read and second read are used to warm up for background search, third read without using spider_split_read and spider_semi_split_read will fetch the remaining data source in a single last fetch.
  • -1 The table parameter is adopted.
  • 0 Records are usually retrieved.
  • 1 or more Number of records.
• Scope: Global, Session
• Dynamic: Yes
• Data Type: numeric
• Default Session Value: -1
• Default Table Value: 2
• DSN Parameter Name: frd

spider_force_commit

• Description: Behavior when error occurs on xa prepare, xa commit, and xa rollback.
  • 0 The error is returned.
  • 1 The error is returned when xid doesn't exist, otherwise continues processing
  • 2 Processing continues disregarding all the errors.
• Scope: Global, Session
• Dynamic: Yes
• Data Type: numeric
• Default Session Value: 0

spider_general_log

• Description: Whether to log all Spider commands to the general log. Error codes are logged according to the spider_log_result_errors variable.
  • OFF No commands are logged.
  • ON Commands are logged to the general log.
• Scope: Global, Session
• Dynamic: Yes
• Data Type: boolean
• Default Session Value: OFF

spider_init_sql_alloc_size

• Description: Initial size of the local SQL buffer.
  • -1 The table parameter is adopted.
  • 0 or more Size of the buffer.
• Scope: Global, Session
• Dynamic: Yes
• Data Type: numeric
• Default Session Value: -1
• Default Table Value: 1024
• DSN Parameter Name: isa

spider_internal_limit

• Description: Limit the number of records when acquired from remote server.
  • -1 The table parameter is adopted.
  • 0 or more Number of records limit.
• Scope: Global, Session
• Dynamic: Yes
• Data Type: numeric
• Default Session Value: -1
• Default Table Value: 9223372036854775807
• DSN Parameter Name: ilm

spider_internal_offset

• Description: Skip records when acquired from the remote server.
  • -1 The table parameter is adopted.
  • 0 or more : Number of records to skip.
• Scope: Global, Session
• Dynamic: Yes
• Data Type: numeric
• Default Session Value: -1
• Default Table Value: 0
• DSN Parameter Name: ios

spider_internal_optimize

• Description: Push down of OPTIMIZE TABLE
  • -1 The table parameter is adopted.
  • 0 Transmitted.
  • 1 Not transmitted.
• Scope: Global, Session
• Dynamic: Yes
• Data Type: numeric
• Default Session Value: -1
• Default Table Value: 0
• DSN Parameter Name: iom

spider_internal_optimize_local

• Description: Whether to transmit to the remote server when OPTIMIZE TABLE is executed on the local server.
  • -1 The table parameter is adopted.
  • 0 Not transmitted.
  • 1 Transmitted.
• Default Session Value: -1
• DSN Parameter Name: iol

spider_internal_sql_log_off

• Description: Whether SQL transmitted to the remote server is logged to the general log.
  • OFF Log SQL to remote server.
  • ON Do not log SQL to remote server.
• Scope: Global, Session
• Dynamic: Yes
• Data Type: boolean
• Default Session Value: ON

spider_internal_unlock

• Description: Whether or not unlock tables is transmitted to the connection of the table used with the SELECT.
  • 0 Not transmitted.
  • 1 Transmitted.
• Data Type: numeric
• Default Session Value: 0

spider_internal_xa

• Description: Whether XA implementation is at the server or the storage engine level. Set different server ids in the all server instances for generating different xa id when using Server.
  • OFF Engine protocol.
  • ON Server protocol.
• Scope: Global, Session
• Dynamic: Yes
• Data Type: boolean
• Default Session Value: OFF

spider_internal_xa_snapshot

• Description: When using MariaDB internal XA implementation and START TRANSACTION WITH CONSISTENT SNAPSHOT. There is a limitation for reading consistent data on all backends.
  • 0 Raise error when use a spider table
  • 1 Raise error when START TRANSACTION
  • 2 Take a consistent CONSISTENT SNAPSHOT on each backend . But global consistency is lost
  • 3 Take a start transaction with XA but remove CONSISTENT SNAPSHOT.
• Scope: Global, Session
• Dynamic: Yes
• Data Type: numeric
• Default Session Value: 0

spider_local_lock_table

• Description: Whether or not LOCK TABLES is pushed down to the remote server.
  • 0 Transmitted.
  • 1 Not transmitted.
• Scope: Global, Session
• Dynamic: Yes
• Data Type: numeric
• Default Session Value: 0

spider_lock_exchange

• Description: Whether to convert SELECT LOCK IN SHARE MODE and SELECT FOR UPDATE to LOCK TABLE
  • 0 Not converted.
  • 1 Converted.
• Scope: Global, Session
• Dynamic: Yes
• Data Type: numeric
• Default Session Value: 0

spider_log_result_errors

• Description: Whether to log results from the data node to the Spider node into the error log. The default value is 0, no logging.
  • 0 : No errors are logged.
  • 1 : Errors are logged.
  • 2 : As for 1, as well as logging warning summaries.
  • 3 : As for 2 as well as logging warning details.
  • 4 : As for 3 as well as logging all result summaries.

spider_low_mem_read

• Description: Whether to use low memory mode when a query internally issued to a remote server is executed and gets a result list.
  • -1 The table parameter is adopted.
  • 0 Low memory mode is not used.
  • 0 Low memory mode is used.
• Data Type: numeric
• Default Value: -1

spider_max_order

• Description: Maximum number of columns for ORDER BY.
  • -1 The table parameter is adopted.
  • 0 and more Maximum number of columns.
• Scope: Global, Session
• Dynamic: Yes
• Data Type: numeric
• Data Range: -1,32767
• Default Session Value: -1
• Default Table Value: 32767#
• DSN Parameter Name: mod

spider_multi_split_read

• Description: Determines whether to divide a statement into multiple SQL statements sent to the remote backend server when a range retrieval is resolved to multiple conditions by the optimizer.
  • -1 The table parameter is adopted.
  • 0 Not divided.
  • 1 Divided.
• Scope: Global, Session
• Dynamic: Yes
• Data Type: numeric
• Default Session Value: -1
• Default Table Value: 0
• DSN Parameter Name: msr

spider_net_read_timeout

• Description: The TCP timeout in seconds to declare remote backend not responsive when reading from a connection. Can be changed for slow latency networks.
  • -1 The table parameter is adopted.
  • 0 Less than 1 second timeout.
  • 1 and more Timeout in seconds.
• Scope: Global, Session
• Dynamic: Yes
• Data Type: numeric
• Max Value: 2147483647
• Default Session Value: -1
• Default Table Value: 0
• DSN Parameter Name: nrt

spider_net_write_timeout

• Description: The TCP timeout in seconds to declare remote backend not responsive when writing to a connection. Can be changed for slow latency networks.
  • -1 The table parameter is adopted.
  • 0 Less than 1 second timeout.
  • 1 and more Timeout in seconds.
• Scope: Global, Session
• Dynamic: Yes
• Data Type: numeric
• Max Value: 2147483647
• Default Session Value: -1
• Default Table Value: 0
• DSN Parameter Name: nwt

spider_ping_interval_at_trx_start

• Description: Reset the connection keepalive timeout in seconds by sending a ping.
  • 0 At every transaction.
  • 1 and more Number of seconds.
• Scope: Global, Session
• Dynamic: Yes
• Data Type: numeric
• Max Value: 2147483647
• Default Session Value: 3600

spider_quick_mode

• Description: Type of backend query buffering, either buffer on the remote backend server or in the local buffer.
  • -1 The table parameter is adopted.
  • 0 Local buffering, it acquires records collectively.
  • 1 Remote buffering, acquisition record per record. Interrupt does not wait and recover on context switch back.
  • 2 Remote buffering, acquisition record per record. Interrupt wait the end of the acquisition
• Scope: Global, Session
• Dynamic: Yes
• Data Type: numeric
• Default Session Value: -1
• Default Table Value: 0
• DSN Parameter Name: qmd

spider_quick_page_size

• Description: Number of records in a page when acquired record by record.
  • -1 The table parameter is adopted.
  • 0 or more Number of records.
• Scope: Global, Session
• Dynamic: Yes
• Data Type: numeric
• Default Session Value: -1
• Default Table Value: 100
• DSN Parameter Name: qps

spider_read_only_mode

• Description: Whether to set Spider tables to read only
  • -1 The table parameter is adopted.
  • 0 Writeable
  • 1 Read only
• Scope: Global, Session
• Dynamic: Yes
• Data Type: numeric
• Default Session Value: -1
• Default Table Value: 0
• DSN Parameter Name: rom

spider_remote_access_charset

• Description: Force session character set when connecting to the backend server. Can improve connection time performance.
• Scope: Global, Session
• Dynamic: Yes
• Data Type: string
• Default Session Value: null

spider_remote_autocommit

• Description: Set auto commit mode when connecting to the backend server. Can improve connection time performance.
  • -1 Don't set.
  • 0 autocommit = 0
  • 1 autocommit = 1
• Scope: Global, Session
• Dynamic: Yes
• Data Type: numeric
• Default Session Value: -1

spider_remote_default_database

• Description: Set the local default database when connecting to the backend server. Can improve connection time performance.
  • 0 OFF
  • 1 ON
• Scope: Global, Session
• Dynamic: Yes
• Data Type: boolean
• Default Session Value: ON

spider_remote_sql_log_off

• Description: Set sql_log_off when connecting to the backend server.
  • -1 Don't set.
  • 0 sql_log_off = 0
  • 1 sql_log_off = 1
• Scope: Global, Session
• Dynamic: Yes
• Data Type: numeric
• Default Session Value: -1

spider_remote_time_zone

• Description: Force time zone when connecting to the backend. Can improve the performance of the connection if you know the time zone.
• Scope: Global, Session
• Dynamic: Yes
• Data Type: string
• Default Session Value: null

spider_remote_trx_isolation

• Description: Set transaction isolation level when connecting to the backend server.
  • -1 Don't set.
  • 0 READ UNCOMMITTED
  • 1 READ COMMITTED
  • 2 REPEATABLE READ
  • 3 SERIALIZABLE
• Scope: Global, Session
• Dynamic: Yes
• Data Type: numeric
• Default Session Value: -1

spider_reset_sql_alloc

• Description: Reset per connection SQL buffer after SQL is executed.
  • -1 The table parameter is adopted.
  • 0 Not reset.
  • 1 Reset.
• Scope: Global, Session
• Dynamic: Yes
• Data Type: numeric
• Default Session Value: -1
• Default Table Value: 1
• DSN Parameter Name: rsa

spider_same_server_link

• Description: Enable linking a table to the same local instance.
  • 0 OFF
  • 1 ON
• Scope: Global, Session
• Dynamic: Yes
• Data Type: boolean
• Default Session Value: OFF

spider_second_read

• Description: Number of second read records on the backend server when the first records are found from spider_first_read, the engine will continue scanning a range adding a LIMIT spider_first_read, spider_second_read.
  • -1 The table parameter is adopted.
  • 0 Records are usually retrieved.
  • 1 or more Number of records.
• Scope: Global, Session
• Dynamic: Yes
• Default Session Value: -1
• Default Table Value: 9223372036854775807
• DSN Parameter Name: srd

spider_select_column_mode

• Description: Set preferred mode of column retrieval from remote backend server.
  • -1 The table parameter is adopted.
  • 0 Use index columns if the SELECT statement can solve by using an index, otherwise use all columns.
  • 1 Use columns that are judged necessary.
• Scope: Global, Session
• Dynamic: Yes
• Data Type: numeric
• Default Session Value: -1
• Default Table Value: 1
• DSN Parameter Name: scm

spider_selupd_lock_mode

• Description: Type of local lock mode on INSERT SELECT.
  • -1 The table parameter is adopted.
  • 0 No lock taken.
  • 1 Shared lock taken.
  • 2 Exclusive lock taken.
• Scope: Global, Session
• Dynamic: Yes
• Data Type: numeric
• Default Session Value: -1
• Default Table Value: 1
• DSN Parameter Name: slm#

spider_semi_split_read

• Description: Whether or not to use chunk retrieval with offset and limit parameter on the remote backend server SQL when using spider_split_read.
  • -1 The table parameter is adopted.
  • 0 Chunk retrieval not used.
  • 1 or more Chunk retrieval used.
• Scope: Global, Session
• Dynamic: Yes
• Data Type: numeric
• Default Session Value: -1
• Default Table Value: 0
• DSN Parameter Name: ssr#

spider_semi_split_read_limit

• Description: The limit value for semi_split_read.
  • -1 The table parameter is adopted.
  • 0 or more The limit value.
• Scope: Global, Session
• Dynamic: Yes
• Data Type: numeric
• Default Session Value: -1
• Default Table Value: 9223372036854775807
• DSN Parameter Name: ssl#

spider_semi_table_lock

• Description: For non transactional storage engines, add LOCK TABLES to the remote backends during SQL execution to preserve consistency between roundtrips.
  • 0 Off
  • 1 On
• Scope: Global, Session
• Dynamic: Yes
• Data Type: boolean
• Default Session Value: OFF
• DSN Parameter Name: stl#

spider_semi_table_lock_connection

• Description:Use multiple connections for semi_table_lock.
  • -1 The table parameter is adopted.
  • 0 Use same connection.
  • 1 Use different connection.
• Scope: Global, Session
• Dynamic: Yes
• Data Type: numeric
• Default Session Value: -1
• Default Table Value: 1
• DSN Parameter Name: stc#

spider_semi_trx

• Description: Used to control backend consistency of transactions when an SQL statement is split into multiple statements to the backend. Consistency can be preserved or relaxed. Auto-committed SQL will be encapsulated inside a transaction on the remote backend. You should use spider_semi_trx_isolation=2, if you use read commited or read uncommitted to force consistency.
  • 0 OFF
  • 1 ON
• Scope: Global, Session
• Dynamic: Yes
• Data Type: boolean
• Default Session Value: ON

spider_semi_trx_isolation

• Description: Set consistency during range SQL execution when spider_sync_trx_isolation is 1
  • -1 OFF
  • 0 READ UNCOMMITTED
  • 1 READ COMMITTED
  • 2 REPEATABLE READ
  • 3 SERIALIZABLE
• Scope: Global, Session
• Dynamic: Yes
• Data Type: numeric
• Default Session Value: -1

spider_skip_default_condition

• Description: Whether or not to compute condition push down.
  • -1 The table parameter is adopted.
  • 0 Compute condition push down.
  • 1 Don't compute condition push down.
• Scope: Global, Session
• Dynamic: Yes
• Data Type: numeric
• Default Session Value: -1
• Default Table Value: 0
• DSN Parameter Name: sdc

spider_split_read

• Description: Number of records in the chunk used to retry the result when a range query is sent to a remote backend server.
  • -1 The table parameter is adopted.
  • 0 or more Number of records.
• Scope: Global, Session
• Dynamic: Yes
• Data Type: numeric
• Default Session Value: -1
• Default Table Value: 9223372036854775807
• DSN Parameter Name: srd

spider_sts_bg_mode

• Description: Mode of table statistic at background. Background confirmation is enabled by default at the table level, one thread per partition is created to maintain table status. Disable when sts_interval=0, effective with the default sts_interval = 10.
  • -1 The table parameter is adopted.
  • 0 Background confirmation is disabled.
  • 1 Background confirmation is enabled.
• Scope: Global, Session
• Dynamic: Yes
• Data Type: numeric
• Default Session Value: -1
• Default Table Value: 1
• DSN Parameter Name: sbm

spider_sts_interval

• Description: Time interval of table statistics. Set to 0 to always get the newest information from remote servers.
  • -1 The table parameter is adopted.
  • 1 or more Interval in seconds for table state confirmation.
• Scope: Global, Session
• Dynamic: Yes
• Data Type: numeric
• Default Session Value: -1
• Default Table Value: 10
• DSN Parameter Name: siv

spider_sts_mode

• Description: Mode for table statistics. The SHOW command is used at the table level default.
  • -1,0 The table parameter is adopted.
  • 1 The show command is used.
  • 2 The information schema is used.
• Scope: Global, Session
• Dynamic: Yes
• Data Type: numeric
• Default Session Value: -1
• Default Table Value: 1
• DSN Parameter Name: smd

spider_sts_sync

• Description: Whether or not table statistics are synchronized in partitioned tables.
  • -1 The table parameter is adopted.
  • 0 No synchronization.
  • 1 Table state is synchronized when opening a table, no more synchronization later.
  • 2 Synchronization.
• Scope: Global, Session
• Dynamic: Yes
• Data Type: numeric
• Default Session Value: -1
• Default Table Value: 0
• DSN Parameter Name: ssy

spider_support_xa

• Description: Use xa protocol for mirroring and for multi shard transactions.
  • 1 Use xa protocol
  • 0 Don't use xa protocol.
• Scope: Global
• Dynamic: No
• Data Type: numeric
• Default Table Value: 1

spider_sync_autocommit

• Description: Whether or not the local AUTO COMMIT is pushed down to remote backends.
  • OFF Not pushed down.
  • ON Pushed down.
• Scope: Global
• Dynamic: Yes
• Data Type: boolean
• Default Session Value: ON

spider_sync_time_zone

• Description: Whether or not the local TIME ZONE is pushed down to remote backends.
  • OFF Not pushed down.
  • ON Pushed down.
• Scope: Global
• Dynamic: Yes
• Data Type: boolean
• Default Session Value: ON

spider_sync_trx_isolation

• Description: Whether or not the local transaction isolation level is pushed down to remote backends.
  • ON Not pushed down.
  • OFF Pushed down.
• Scope: Global
• Dynamic: Yes
• Data Type: boolean
• Default Session Value: ON

spider_table_init_error_interval

• Description: Interval in seconds for which the same error code is returned if the table init fails, Used to protect against endless loops in the table link.
• Scope: Global
• Dynamic: Yes
• Data Type: numeric
• Default Value: 1
• Range: -1 to 4294967295

spider_udf_ct_bulk_insert_interval

• Description: Interval in milliseconds between bulk inserts at copying.
  • -1 The UDF parameter is adopted.
  • 0 and more Time in milliseconds.
• Scope: Global
• Dynamic: Yes
• Data Type: numeric
• Default Session Value: -1
• Default Table Value: 4294967295
• Range: -1 to 4294967295

spider_udf_ct_bulk_insert_rows

• Description: Number of rows inserted at a time during a bulk insert when copying.
  • -1, 0: The table parameter is adopted.
  • 1 or more Number of rows
• Scope: Global
• Dynamic: Yes
• Data Type: numeric
• Default Session Value: -1
• Default Table Value: 18446744073709551615
• Range: -1# to 9223372036854775807

spider_udf_ds_bulk_insert_rows

• Description: Number of rows inserted at a time during a bulk insert when result set is stored in a temporary table on executing a UDF.
  • -1, 0 The UDF parameter is adopted.
  • 1 or more Number of rows
• Scope: Global
• Dynamic: Yes
• Data Type: numeric
• Default Session Value: -1
• Default Table Value: 18446744073709551615
• Range: -1 upwards

spider_udf_ds_table_loop_mode

• Description: Whether or not the result set is stored in same temporary table if the temporary table list count at UDF is less than the result set count at executing UDF.
  • -1 The table parameter is adopted.
  • 0 Drop records.
  • 1 Insert last table.
  • 2 Insert first table and loop again.
• Scope: Global, Session
• Dynamic: Yes
• Data Type: numeric
• Default Session Value: -1

spider_udf_ds_use_real_table

spider_udf_table_lock_mutex_count

spider_udf_table_mon_mutex_count

spider_use_all_conns_snapshot

• Description: Whether or not START TRANSACTION WITH SNAPSHOT is passed to all connections
  • OFF Not passed.
  • ON Passed to all connections.
• Scope: Global
• Dynamic: Yes
• Data Type: boolean
• Default Session Value: ON

spider_use_consistent_snapshot

• Description: Whether or not a local START TRANSACTION WITH CONSISTENT is pushed down to backends.
  • OFF Not pushed down .
  • ON Pushed down.
• Scope: Global
• Dynamic: Yes
• Data Type: boolean
• Default Session Value: ON

spider_use_default_database

• Description: Whether or not the default database is used.
  • OFF Default database not used.
  • ON Use default database.
• Scope: Global
• Dynamic: Yes
• Data Type: boolean
• Default Session Value: ON

spider_use_flash_logs

• Description: Whether or not FLUSH LOGS is pushed down to remote backends
  • OFF Not pushed down.
  • ON Pushed down.
• Scope: Global, Session
• Dynamic: Yes
• Data Type: boolean
• Default Session Value: OFF

spider_use_handler

• Description: Conversion of HANDLER SQL command. Handler conversion will be disabled if spider_sync_trx_isolation =0 to avoid to using handler command on serializable isolation level.
  • 0 HANDLER converted to SELECT
  • 1 HANDLER passed to the backend
  • 2 SQL is converted to HANDLER
  • 3 SQL is converted to HANDLER and HANDLER is converted to SQL
• Scope: Global, Session
• Dynamic: Yes
• Data Type: numeric
• Default Session Value: 0
• DSN Parameter Name: uhd

spider_use_pushdown_udf

• Description: When engine_condition_pushdown=1 and a UDF function is used in a condition, determines whether the UDF execution is local or pushed down.
  • -1 The table parameter is adopted.
  • 0 Not transmitted.
  • 1 Transmitted.
• Scope: Global, Session
• Dynamic: Yes
• Data Type: numeric
• Default Session Value: -1
• Default Table Value: 1
• DSN Parameter Name: upu

spider_use_snapshot_with_flush_tables

• Description: On START TRANSACTION WITH CONSISTENT send to remote backend FLUSH TABLE WITH READ LOCK If this value is 1 or 2, FLUSH LOGS and UNLOCK TABLES are encapsulated
  • 0 : It doesn't add.
  • 1 : It adds. (Only when spider_use_all_conns_snapshot is 1)
  • 2 : The snap shot synchronizes by using lock tables and flush tables at the xa transaction level. (Only when spider_use_all_conns_snapshot is 1, it is effective.)
• Scope: Global, Session
• Dynamic: Yes
• Data Type: numeric
• Default Session Value: 0

spider_use_table_charset

• Description: Whether or not to use the local table character set for the backend connection.
  • -1 The table parameter is adopted.
  • 0 Use utf8.
  • 1 Use table character set.
• Scope: Global, Session
• Dynamic: Yes
• Data Type: numeric
• Default Session Value: -1
• Default Table Value: 1
• DSN Parameter Name: utc