ApsaraDB RDS:Manage instance parameters in the console

Prerequisites

Before you begin, ensure that:

• The instance type is General-purpose or Dedicated. Shared instances are not supported.

• The billing method is Subscription or pay-as-you-go. Serverless instances are not supported.

For unsupported instances, set instance parameters using SQL commands instead.

Usage notes

• Only parameters listed on the Modifiable Parameters tab can be modified. Parameters not shown in the console cannot be changed.

• Changes typically take effect within 10 seconds without a restart. For the exact effective time of each parameter, see the parameter details in the appendix.

• For Cluster Edition primary instances with read-only instances attached: parameter changes on the primary instance are not automatically applied to read-only instances. Configure each read-only instance separately.

• For Trace Flag (TF) parameters: if you manually restart the instance after modifying a TF parameter, the new value is applied after the restart but takes effect after an additional buffer delay of about 10 minutes.

View parameter values

1. Go to the Instances page. In the top navigation bar, select the region where your instance resides, then click the instance ID.

2. In the left navigation pane, click Parameters. The current value of each parameter is listed in the parameter table.

Modify parameter values

1. Go to the Instances page. In the top navigation bar, select the region where your instance resides, then click the instance ID.

2. In the left navigation pane, click Parameters.

3. On the Modifiable Parameters tab, find the parameter to modify and click the icon in the Running Value column.

4. Enter the new value and click OK.

5. Click Apply Changes, then click OK in the confirmation dialog.

Query parameter modification history

1. Go to the Instances page. In the top navigation bar, select the region where your instance resides, then click the instance ID.

2. In the left navigation pane, click Parameters.

3. Click the Edit History tab, select a time range, and click OK.

FAQ

Do parameter changes take effect immediately? Is a restart required?

Changes typically take effect within 10 seconds. No restart is required for any of the parameters listed in the console.

The exception is Trace Flag (TF) parameters: if you manually restart the instance after modifying a TF parameter, the new TF value is applied after the restart but takes effect after an additional buffer delay of about 10 minutes.

Why aren't my parameter changes taking effect?

Check the following in order:

1. Did you click Apply Changes? After editing a parameter value and clicking OK in the edit dialog, you must also click Apply Changes to submit the change. If you skipped this step, the modification was not submitted.

2. Is the parameter a Trace Flag? TF parameters applied after a manual instance restart have an additional buffer delay of about 10 minutes before they take effect.

3. Has the effective time elapsed? Some parameters, such as rds_slow_log_threshold and rds_capture_sql_param, take effect in about 5 minutes. Wait for the effective time listed in the parameter table.

Appendix: Modifiable parameters

For detailed descriptions of each parameter, see the Microsoft SQL Server configuration options documentation.

Server configuration parameters

Parameter name	Description	Default value	Value range
Ad Hoc Distributed Queries	Enables ad hoc distributed queries.	0	[0-1]
Database Mail XPs	Enables Database Mail.	0	[0-1]
blocked process threshold (s)	Specifies the threshold, in seconds, at which blocked process reports are generated.	0	[0-86400]
clr enabled	Specifies whether SQL Server can run user assemblies.	0	[0-1]
clr strict security	Controls the SAFE, EXTERNAL ACCESS, and UNSAFE permissions in SQL Server.	0	[0-1]
cost threshold for parallelism	Sets the cost threshold above which SQL Server creates and runs parallel plans for a query.	5	[0-32767]
default full-text language	Specifies the default language for full-text indexes.	1033	[0-6000]
default language	Specifies the default language for all newly created login accounts.	0	[0-33]
filestream access level	Changes the FILESTREAM access level for this SQL Server instance.	0	[0-2]
max degree of parallelism	Sets the maximum number of processors used in a parallel plan.	2	[0-64]
remote query timeout (s)	Specifies how long, in seconds, a remote operation can run before SQL Server times out.	600	[0-2147183647]
remote login timeout (s)	Specifies the number of seconds to wait before returning from a failed attempt to log in to a remote server.	10	[0-2147183647]
query wait (s)	Specifies the time, in seconds, that a query waits for resources before timing out.	30	[-1-38400]
optimize for ad hoc workloads	Improves plan cache efficiency for workloads with many single-use ad hoc batches.	0	[0-1]
nested triggers	Controls whether triggers can cascade — that is, whether a trigger can perform an action that initiates another trigger.	1	[0-1]
max worker threads	Sets the maximum number of worker threads available to SQL Server processes.	0	[128-65535]
max text repl size (B)	Specifies the maximum size, in bytes, of text, ntext, varchar(max), nvarchar(max), varbinary(max), xml, and image data that can be added to a replicated column in a single INSERT, UPDATE, WRITETEXT, or UPDATETEXT statement.	65536	[0-2147483647]
remote proc trans	Enables a Microsoft Distributed Transaction Coordinator (MS DTC) transaction to protect server-to-server procedure operations.	0	[0-1]
query governor cost limit	Sets an upper limit on the estimated cost allowed for a query to run.	0	[0-2147483647]
recovery interval (min)	Sets the maximum number of minutes per database that SQL Server should use for recovering databases.	0	[0-30]
min memory per query (KB)	Sets the minimum amount of memory, in KB, allocated for the execution of a query.	1024	[512-2147483647]
in-doubt xact resolution	Controls the default outcome for transactions that MS DTC cannot resolve.	0	[0-2]
rds_slow_log_threshold	Sets the threshold, in milliseconds (ms), for capturing slow SQL statements. Statements that exceed this threshold are recorded as slow query logs. Takes effect in about 5 minutes without a restart. Set a threshold of 1000 ms or higher — a lower value captures excessive SQL statements, which hinders log filtering and degrades instance performance.	0	[0-60000]
rds_capture_sql_param	Controls whether full SQL parameter details are displayed in Audit Log and Slow Log Details. Set to 1 to enable. Takes effect in about 5 minutes without a restart.	0	[0-1]

Effects of enabling `rds_capture_sql_param`

	Before enabling	After enabling	Impact after enabling
SQL logging	Only the SQL statement template is recorded. Specific parameter values are not captured.	Full SQL parameter details are displayed.	DAS features such as SQL Explorer and Slow Log Statistics cannot aggregate similar SQL statements.

Important

Before enabling this feature, make sure your environment is secure. Enabling it changes the log format and prevents DAS from aggregating similar SQL statements. It also records actual parameter values in plaintext, which may expose sensitive data such as passwords.

What's next

• Query the current parameter configuration using the API: DescribeParameters

• Modify instance parameters using the API: ModifyParameter

• Set instance parameters using SQL commands: Set instance parameters using SQL commands