View and modify instance-level and database-level parameters in the PolarDB-X 1.0 console to tune connection behavior, query performance, and DDL execution.
Usage notes
Read-only instances: only database-level parameters are configurable. Instance-level parameters are not available.
Some parameters are supported only on specific versions. Check the Supported version column in the parameter reference tables below.
Parameters with Yes in the Restart column take effect only after you restart the instance. Plan parameter changes during a maintenance window to minimize impact on production traffic.
Parameter reference
PolarDB-X 1.0 parameters are organized into two levels:
Instance: control connection and query behavior at the instance level, affecting all databases in the instance.
Database: control connection pool and query behavior between a specific database and its underlying ApsaraDB for RDS shards.
Instance-level parameters
| Parameter | Description | Supported version |
|---|---|---|
SLOW_SQL_TIME | Threshold for slow queries. Queries that exceed this threshold are recorded in slow logical SQL logs. | 5.3.4-15378085 or later |
LOGIC_IDLE_TIMEOUT | Timeout period for idle connections between the client and the PolarDB-X 1.0 instance. Unit: milliseconds. | 5.3.4-15378085 or later |
MAX_ALLOWED_PACKET | Maximum packet size between the client and the PolarDB-X 1.0 instance. Unit: bytes. | 5.3.4-15378085 or later |
PURE_ASYNC_DDL_MODE | Controls the execution mode of data definition language (DDL) statements when the asynchronous DDL engine is enabled. When set to true, the client returns immediately after submitting a DDL statement; use DDL management statements to check execution status. When set to false, the client waits until DDL execution completes (synchronous mode). | 5.3.4-15378085 or later |
ENABLE_RANDOM_PHY_TABLE_NAME | Controls whether physical tables use randomly generated names. | 5.4.4 or later |
Database-level parameters
| Parameter | Description | Supported version |
|---|---|---|
MAX_POOL_SIZE | Maximum number of connections between a PolarDB-X 1.0 database and a single ApsaraDB for RDS database shard. | All versions |
MIN_POOL_SIZE | Minimum number of connections between a PolarDB-X 1.0 database and a single ApsaraDB for RDS database shard. | All versions |
IDLE_TIMEOUT | Timeout period for idle connections between a PolarDB-X 1.0 database and an ApsaraDB for RDS database shard. | All versions |
SOCKET_TIMEOUT | Timeout period for SQL queries sent from a PolarDB-X 1.0 database to an ApsaraDB for RDS database. | All versions |
FORBID_EXECUTE_DML_ALL | Controls whether full-table deletion and update operations are prohibited. | All versions |
TEMP_TABLE_MAX_ROWS | Size of the intermediate temporary table used during distributed queries. | 5.3.4-15378085 or later |
MERGE_UNION_SIZE | Maximum number of table shards that can be combined using the UNION statement when querying multiple table shards in a database. | 5.3.4-15378085 or later |
Prerequisites
Before you begin, ensure that you have:
A PolarDB-X 1.0 instance with the required version for the parameters you want to modify
Sufficient permissions to access the PolarDB for Xscale console
Modify instance parameters
Log on to the PolarDB for Xscale console.
In the top navigation bar, select the region where your instance is located.
In the left-side navigation pane, click Instances.
Click the ID of the target instance.
In the left-side navigation pane, choose Diagnostics and Optimization > Parameter Settings.
Click the Instance tab.
Find the target parameter and click
in the Parameter Value column.Click
in the Description column to view the parameter description and valid value range.
In the dialog box, enter a value within the Valid Values range and click OK.
If the value is outside the valid range, an error message appears when you click Submit.
Click Submit.
If the Restart column for a parameter shows Yes, restart the instance after submitting for the new value to take effect.
Modify database parameters
Log on to the PolarDB for Xscale console.
In the top navigation bar, select the region where your instance is located.
In the left-side navigation pane, click Instances.
Click the ID of the target instance.
In the left-side navigation pane, choose Diagnostics and Optimization > Parameter Settings.
Click the Database tab, then click the name of the target database.
Find the target parameter and click
in the Parameter Value column.Click in the Description column to view the parameter description and valid value range.
In the dialog box, enter a value within the Valid Values range and click OK.
If the value is outside the valid range, an error message appears when you click Submit.
Click Submit.
If the Restart column for a parameter shows Yes, restart the instance after submitting for the new value to take effect.