ApsaraDB RDS:Manage instance parameters

Parameter

Description

Default

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 (s), 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 queries.

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 logins.

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 (s) a remote operation can run before it times out.

600

[0-2147183647]

remote login timeout (s)

Specifies how long in seconds (s) to wait for a remote login attempt before it times out.

10

[0-2147183647]

query wait (s)

Specifies how long in seconds (s) 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.

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 the maximum estimated cost for running a query.

0

[0-2147483647]

recovery interval (min)

Sets the maximum time, in minutes, that SQL Server requires to recover a database.

0

[0-30]

min memory per query (KB)

Sets the minimum memory (in KB) allocated for a query's execution.

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

Specifies the threshold in milliseconds (ms) for capturing slow SQL statements on an instance. SQL statements that exceed this threshold are recorded as slow query logs. Changes to this parameter take effect in approximately 5 minutes and do not require an instance restart.

0

[0-60000]

rds_capture_sql_param

Controls whether to display full SQL parameter details in the Audit Log and Slow Log Details pages. Set this parameter to 1 to enable the feature (default: 0). Changes to this parameter take effect in approximately 5 minutes and do not require an instance restart.

(@n int, @keyword nvarchar(100))
SELECT
    TOP (@n) PersonID,
    FullName,
    PhoneNumber
FROM
    Application.People
WHERE
    FullName LIKE @keyword
    OR PreferredName LIKE @keyword
ORDER BY
    PersonID;

exec sp_executesql N'
SELECT TOP (@n) PersonID, FullName, PhoneNumber
FROM    Application.People
WHERE   FullName LIKE @keyword OR
PreferredName LIKE @keyword
ORDER BY PersonID;',
N'@n int,@keyword nvarchar(100)',
@n = 5,
@keyword = N'%Kim%'

0

[0-1]

rds_sql_literal_masking

Controls whether to mask SQL literals in audit logs and slow query logs. Set this parameter to 1 to enable masking, or 0 (default) to disable it. When enabled, string literals in SQL statements are replaced with '***', numeric literals with *, and hexadecimal literals with 0x***. DDL statements are not affected. Changes to this parameter take effect in approximately 5 minutes and do not require an instance restart.

DELETE FROM
    test_mask
WHERE
    id = 3
    AND name = N'Wang Wu'
    AND phone = '12345678910'

DELETE FROM
    test_mask
WHERE
    id = *
    AND name = N'***'
    AND phone = '***'

0

0 or 1

Parameter

Description

Default

Value range

1204

Returns the resources, lock types, and command involved in a deadlock.

0

[0-1]

1211

Disables lock escalation that is based on memory pressure or the number of locks. This prevents the SQL Server Database Engine from escalating row or page locks to table locks.

0

[0-1]

1222

Returns the resources and types of locks that are involved in a deadlock and the currently affected command in an XML format that does not conform to any XSD schema.

0

[0-1]

1224

Controls lock escalation behavior. When enabled, SQL Server limits lock escalation based on the number of locks, which helps prevent widespread blocking in high-concurrency scenarios. Compared with Trace Flag 1211, which completely disables lock escalation, Trace Flag 1224 is more flexible and restricts escalation only when potential blocking is detected. It is primarily used in high-concurrency environments to avoid performance issues that are caused by unnecessary table-level locks.

0

[0-1]

2528

Disables parallel checking of objects by using DBCC CHECKDB, DBCC CHECKFILEGROUP, and DBCC CHECKTABLE.

0

[0-1]

3205

Disables hardware compression for tape drives.

0

[0-1]

3226

Suppresses backup log entries.

0

[0-1]

4199

Enables query optimizer (QO) hotfixes that are released in SQL Server cumulative updates and service packs.

0

[0-1]

4616

Makes server-level metadata visible to application roles.

0

[0-1]

6527

Disables memory dump generation on the first out-of-memory exception in CLR integration.

0

[0-1]

692

Disables fast inserts when data is bulk loaded into a heap or clustered index.

0

[0-1]

1117

When a file in a filegroup meets the autogrow threshold, all files in the filegroup grow.

0

[0-1]

1118

Forces page allocations on uniform extents instead of mixed extents to reduce contention on the SGAM page.

0

[0-1]

1262

Optimizes parallel processing for partitioned tables, especially in high-throughput scenarios. When you process large-scale partitioned tables, Trace Flag 1262 can help mitigate performance bottlenecks that are caused by imbalanced load distribution or partition-level parallel processing. This is particularly useful for queries that require parallel access to large amounts of data.

0

[0-1]

2335

Ensures that memory configured for SQL Server remains available for the data cache, query execution, and other consumers.

0

[0-1]

2371

Changes the fixed update statistics threshold to a linear update statistics threshold.

0

[0-1]

2430

Enables alternate lock class cleanup.

0

[0-1]

3604

Sends diagnostic output to the client. It is typically enabled when you use DBCC commands, such as DBCC PAGE, to view information like page structures and metadata. This helps with in-depth performance troubleshooting, such as checking for lock contention or other resource contention. This flag is often used for database performance diagnostics or data structure analysis.

0

[0-1]

6498

Manages memory usage for the compilation of incoming queries to avoid compilation waits for concurrent large queries.

0

[0-1]

8048

Converts NUMA-partitioned memory objects to CPU-partitioned memory objects.

0

[0-1]