wsrep_sync_wait
This page is part of MariaDB's Documentation.
The parent of this page is: System Variables for MariaDB Enterprise Server
Topics on this page:
Overview
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, in 10.4 ES, in 10.3 ES, in 10.2 ES, in 10.6 CS, in 10.5 CS, in 10.4 CS, in 10.3 CS, and in 10.2 CS
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 |
|---|---|---|
| None | Disables causality checks. |
|
| Performs causality checks for read operations, such as SELECT and BEGIN statements. |
|
| Performs causality checks on update operations, such as UPDATE and DELETE statements. |
|
| Performs causality checks on read and update operations, such as SELECT, UPDATE, and DELETE statements. |
|
| Performs causality checks on insert operations, such as INSERT and REPLACE statements. |
|
| Performs causality checks on read and insert operations, such as SELECT, INSERT, and UPDATE statements. |
|
| Performs causality checks on update and insert operations, such as UPDATE, DELETE, INSERT, and REPLACE statements. |
|
| Performs causality checks on read, update, and insert operations, such as SELECT, UPDATE, DELETE, INSERT, and REPLACE statements. |
|
| Performs causality checks on show operations, such as SHOW TABLES statements. |
|
| Performs causality checks on read and show operations, such as SELECT and SHOW TABLES statements. |
|
| Performs causality checks on update and show operations, such as UPDATE, DELETE SHOW TABLES statements. |
|
| Performs causality checks on read, update, and show operations, such as SELECT, UPDATE, DELETE, and SHOW TABLES statements. |
|
| Performs causality checks on insert and show operations, such as INSERT, REPLACE, and SHOW TABLES statements. |
|
| Performs causality checks on read, insert, and show operations, such as SELECT, INSERT, REPLACE, and SHOW TABLES statements. |
|
| Performs causality checks on update, insert, and show operations, such as UPDATE, DELETE, INSERT, REPLACE, and SHOW TABLES statements. |
|
| Performs causality checks on show operations, such as SELECT, UPDATE, DELETE, INSERT, REPLACE, and SHOW TABLES statements. |
PARAMETERS
Command-line | --wsrep_sync_wait[=#] |
Configuration file | Supported |
Dynamic | Yes |
Scope | Global, Session |
Data Type | INT UNSIGNED |
Minimum Value | 0 |
Maximum Value | 15 |
Product Default Value | 0 |
CHANGE HISTORY
Release Series | History |
|---|---|
10.6 Enterprise |
|
10.6 Community |
|
10.5 Enterprise |
|
10.5 Community |
|
10.4 Enterprise |
|
10.4 Community |
|
10.3 Enterprise |
|
10.3 Community |
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10.2 Enterprise |
|
10.2 Community |
|
EXTERNAL REFERENCES
Additional information on this topic may be found in the MariaDB Public Knowledge Base.