wsrep_sync_wait

Bitmask to configure synchronization waits for causality checks on the cluster.

See also: System Variables for MariaDB Enterprise Server 10.6, in 10.5 ES, and in 10.4 ES

DETAILS

Cluster Nodes can perform causality checks in response to certain types of SQL statements.

When an SQL statement triggers a causality check, the node waits for synchronization before executing the query. During synchronization, the node applies any outstanding write-sets from the cluster up to the point where it received the statement. It then executes the statement and returns the result-set.

Enabling causality checks ensures that certain types of queries always execute against the most up to date database state, at the expense of query performance.

This system variable specifies the types of statements that trigger causality checks:

Bitmask

Statement Type

Description

0

None

Disables causality checks.

1

  • Read

Performs causality checks for read operations, such as SELECT and BEGIN statements.

2

  • Update

Performs causality checks on update operations, such as UPDATE and DELETE statements.

3

  • Read

  • Update

Performs causality checks on read and update operations, such as SELECT, UPDATE, and DELETE statements.

4

  • Insert

Performs causality checks on insert operations, such as INSERT and REPLACE statements.

5

  • Read

  • Insert

Performs causality checks on read and insert operations, such as SELECT, INSERT, and UPDATE statements.

6

  • Update

  • Insert

Performs causality checks on update and insert operations, such as UPDATE, DELETE, INSERT, and REPLACE statements.

7

  • Read

  • Update

  • Insert

Performs causality checks on read, update, and insert operations, such as SELECT, UPDATE, DELETE, INSERT, and REPLACE statements.

8

  • Show

Performs causality checks on show operations, such as SHOW TABLES statements.

9

  • Read

  • Show

Performs causality checks on read and show operations, such as SELECT and SHOW TABLES statements.

10

  • Update

  • Show

Performs causality checks on update and show operations, such as UPDATE, DELETE SHOW TABLES statements.

11

  • Read

  • Update

  • Show

Performs causality checks on read, update, and show operations, such as SELECT, UPDATE, DELETE, and SHOW TABLES statements.

12

  • Show

  • Insert

Performs causality checks on insert and show operations, such as INSERT, REPLACE, and SHOW TABLES statements.

13

  • Read

  • Insert

  • Show

Performs causality checks on read, insert, and show operations, such as SELECT, INSERT, REPLACE, and SHOW TABLES statements.

14

  • Update

  • Insert

  • Show

Performs causality checks on update, insert, and show operations, such as UPDATE, DELETE, INSERT, REPLACE, and SHOW TABLES statements.

15

  • Read

  • Update

  • Insert

  • Show

Performs causality checks on show operations, such as SELECT, UPDATE, DELETE, INSERT, REPLACE, and SHOW TABLES statements.

PARAMETERS

Dynamic

Yes

Scope

Global, Session

Data Type

INT UNSIGNED

Minimum Value

0

Maximum Value

15

Default Value

0

SKYSQL

Cloud

SkySQL Topology

ES Ver

Default

AWS

HA (Primary/Replica)

10.4

0 (choices: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)

AWS

HA (Primary/Replica)

10.5

0 (choices: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)

AWS

Transactional Standalone

10.4

0 (choices: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)

AWS

Transactional Standalone

10.5

0 (choices: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)

AWS

Distributed Transactions

10.5

Not present (choices: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)

GCP

ColumnStore

10.5

0 (choices: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)

GCP

ColumnStore Multi

10.5

0 (choices: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)

GCP

Galera

10.4

0 (choices: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)

GCP

Galera

10.5

0 (choices: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)

GCP

HA (Primary/Replica)

10.4

0 (choices: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)

GCP

HA (Primary/Replica)

10.5

0 (choices: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)

GCP

HTAP

10.5

0 (choices: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)

GCP

Transactional Standalone

10.4

0 (choices: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)

GCP

Transactional Standalone

10.5

0 (choices: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)

GCP

Distributed Transactions

10.5

Not present (choices: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)

CHANGE HISTORY

Release Series

History

10.6 Enterprise

  • Present starting in MariaDB Enterprise Server 10.6.4-1.

10.5 Enterprise

  • Present starting in MariaDB Enterprise Server 10.5.3-1.

10.4 Enterprise

  • Present starting in MariaDB Enterprise Server 10.4.6-1.

EXTERNAL REFERENCES