Database Autonomy Service:SQL throttling

Scenarios

Throttling modes

Procedure

1. Log on to the DAS console.

2. In the left-side navigation pane, choose Intelligent O&M Center > Instance Monitoring.

3. On the page that appears, find the database instance that you want to manage and click the instance ID. The instance details page appears.

4. In the left-side navigation pane, click Instance Sessions.

5. On the Session Management page, click SQL Throttling.

6. In the dialog box that appears, click Create Throttling Rule.

7. In the Create Throttling Rule dialog box, configure the following parameters based on the database engine.

RDS MySQL

Parameter	Description
Throttling Mode	Select a throttling mode as needed.
SQL Type	Select an SQL type. Valid values: SELECT, UPDATE, DELETE, and INSERT. Note This parameter is required when Throttling Mode is set to Keyword Throttling. Only the following database engines support throttling the INSERT type: RDS MySQL 8.0 PolarDB MySQL 5.7 and 8.0 PolarDB-X 2.0 Throttling for INSERT...SELECT... SQL statements is not supported.
Database	The database for SQL throttling. Note This parameter is required when Throttling Mode is set to SQL Template Throttling.
Maximum Concurrency	The maximum concurrency of SQL statements. The minimum value is 0. Note When SQL statements that meet the throttling policy are executed simultaneously and reach the maximum concurrency, SQL throttling is triggered.
Throttling Duration	The effective time of SQL throttling. Important SQL throttling is an emergency measure. We recommend that you set the throttling duration based on your actual needs and disable it promptly after use.
SQL Keywords	The SQL keywords to be throttled. Note This parameter is required when Throttling Mode is set to Keyword throttling. If you set multiple keywords, the SQL statement must contain all of these keywords to trigger the throttling rule. Multiple keywords are separated by tildes (~) and have no order restriction. For example, if the original statement is: SELECT min(id), max(id) FROM task_event WHERE gmt_modified < '2020-06-21' AND begin_time > '2020-07-09' AND source IN (527) AND id >= 15673 AND id <= 8015673 . The corresponding throttling keywords are: SELECT~min~id~max~id~FROM~task_event~WHERE~gmt_modified~AND~begin_time~AND~source~IN~AND~id~AND~id. Setting only SELECT, INSERT, UPDATE, DELETE as throttling keywords is not supported, and keywords are case-sensitive (some earlier instance versions are not case-sensitive).
SQL Sample	The sample SQL statement to be throttled. Note This parameter is required when Throttling Mode is set to SQL template throttling. For complex SQL statements, DAS will template the SQL sample while ensuring the SQL template remains unchanged. The transformation will not affect the throttling effect. For example, if the input is: select name from das where name = `das` and age = 21 limit 20. It is templated as: select name from das where name = ? and age = ? limit ?. It is rewritten as: select name from das where name = `param0` and age = `param1` limit 20.

RDS PostgreSQL

Parameter	Description
Throttling Mode	RDS PostgreSQL only supports SQL template throttling.
Database	The database for SQL throttling.
Search Path	The search path for SQL throttling. Note Multiple paths are separated by commas ,. The default is information_schema,public.
Maximum Concurrency	The maximum concurrency of SQL statements. The minimum value is 0. Note When SQL statements that meet the throttling policy are executed simultaneously and reach the maximum concurrency, SQL throttling is triggered.
Maximum Waiting Count	The maximum number of waiting SQL statements.
Throttling Duration	The effective time of SQL throttling. Important SQL throttling is an emergency measure. We recommend that you set the throttling duration based on your actual needs and disable it promptly after use.
SQL Sample	The sample SQL statement to be throttled. Note This parameter is required when Throttling Mode is set to SQL Template Throttling. For complex SQL statements, DAS will template the SQL sample while ensuring the SQL template remains unchanged. The transformation will not affect the throttling effect. For example, if the input is: select name from das where name = "das" and age = 21 limit 20. It is templated as: select name from das where name = ? and age = ? limit ?. It is rewritten as: select name from das where name = "param0" and age = "param1" limit 20.

PolarDB MySQL

Parameter	Description
Throttling Mode	Select a throttling mode as needed.
SQL Type	Select an SQL type. Valid values: SELECT, UPDATE, DELETE, INSERT. Note Currently, only the following database engines support throttling the INSERT type: RDS MySQL 8.0 PolarDB MySQL 5.7 and 8.0 PolarDB-X 2.0 Throttling for INSERT...SELECT... SQL statements is not supported.
Maximum Concurrency	The maximum concurrency of SQL statements. The minimum value is 0. Note When SQL statements that meet the throttling policy are executed simultaneously and reach the maximum concurrency, SQL throttling is triggered.
Database	The database for SQL throttling. Note This parameter is required when Throttling Mode is set to SQL Template Throttling.
Throttling Duration	The effective time of SQL throttling. Important SQL throttling is an emergency measure. We recommend that you set the throttling duration based on your actual needs and disable it promptly after use.
SQL Keywords	The SQL keywords to be throttled. Note This parameter is required when Throttling Mode is set to Keyword Throttling. If you set multiple keywords, the SQL statement must contain all of these keywords to trigger the throttling rule. Multiple keywords are separated by tildes (~) and have no order restriction. For example, if the original statement is: SELECT min(id), max(id) FROM task_event WHERE gmt_modified < '2020-06-21' AND begin_time > '2020-07-09' AND source IN (527) AND id >= 15673 AND id <= 8015673 . The corresponding throttling keywords are: SELECT~min~id~max~id~FROM~task_event~WHERE~gmt_modified~AND~begin_time~AND~source~IN~AND~id~AND~id. Setting only SELECT, INSERT, UPDATE, DELETE as throttling keywords is not supported, and keywords are case-sensitive (some earlier instance versions are not case-sensitive).
SQL Sample	The sample SQL statement to be throttled. Note This parameter is required when Throttling Mode is set to SQL Template Throttling. For complex SQL statements, DAS will template the SQL sample while ensuring the SQL template remains unchanged. The transformation will not affect the throttling effect. For example, if the input is: select name from das where name = "das" and age = 21 limit 20. It is templated as: select name from das where name = ? and age = ? limit ?. It is rewritten as: select name from das where name = "param0" and age = "param1" limit 20.

PolarDB-X 2.0

Parameter	Description
Throttling Mode	Select a throttling mode as needed.
SQL Type	Select an SQL type. Valid values: SELECT, UPDATE, DELETE, INSERT. Note Currently, only the following database engines support throttling the INSERT type: RDS MySQL 8.0 PolarDB MySQL 5.7 and 8.0 PolarDB-X 2.0 Throttling for INSERT...SELECT... SQL statements is not supported.
Maximum Concurrency	The maximum concurrency of SQL statements. The minimum value is 0. Note When SQL statements that meet the throttling policy are executed simultaneously and reach the maximum concurrency, SQL throttling is triggered.
Throttling Duration	The effective time of SQL throttling. Important SQL throttling is an emergency measure. We recommend that you set the throttling duration based on your actual needs and disable it promptly after use.
SQL Keywords	The SQL keywords to be throttled. Note This parameter is required when Throttling Mode is set to Keyword Throttling. If you set multiple keywords, the SQL statement must contain all of these keywords to trigger the throttling rule. Multiple keywords are separated by tildes (~) and have no order restriction. For example, if the original statement is: SELECT min(id), max(id) FROM task_event WHERE gmt_modified < '2020-06-21' AND begin_time > '2020-07-09' AND source IN (527) AND id >= 15673 AND id <= 8015673 . The corresponding throttling keywords are: SELECT~min~id~max~id~FROM~task_event~WHERE~gmt_modified~AND~begin_time~AND~source~IN~AND~id~AND~id. Setting only SELECT, INSERT, UPDATE, DELETE as throttling keywords is not supported, and keywords are case-sensitive (some earlier instance versions are not case-sensitive).
SQL Template ID	The SQL template IDs to be throttled. An SQL template ID is an 8-character hexadecimal string. Multiple SQL template IDs are separated by commas ,. Note This parameter is required when PolarDB-X is Enterprise Edition and Throttling Mode is set to SQL Template Throttling.
Minimum SQL Execution Time	The threshold for SQL execution time. When the execution time of an SQL statement exceeds this threshold, the system adds the SQL template ID of this type of SQL statement to the throttling rule. Note This parameter is required when PolarDB-X is Enterprise Edition and Throttling Mode is set to Running Time Throttling.
Maximum Number Of Throttled SQL IDs	The maximum number of SQL template IDs that can be throttled based on execution time. When this limit is reached, the system stops creating throttling rules for other SQL statements whose execution time exceeds the threshold. Note This parameter is required when PolarDB-X is Enterprise Edition and Throttling Mode is set to Running Time Throttling.
Database Account Of Throttled SQL	The database account to which the throttled SQL statements belong. Note This parameter is required when Throttling Mode is set to Keyword Throttling or SQL Template Throttling.

Note

After the target SQL throttling rule is created, if the application uses an SQL statement that contains all the keywords, the system performs the following operations:

• RDS MySQL 5.6, RDS MySQL 5.7 instances and PolarDB MySQL 5.6 clusters will return error 1317 (query execution was interrupted).

• RDS MySQL 8.0 instances, PolarDB MySQL 5.7 and PolarDB MySQL 8.0 clusters will put the relevant SQL statements in the Concurrency control waiting state until the number of waiting statements exceeds the value of the ccl_max_waiting_count parameter (if the instance version supports this parameter). Then, an error code and error description Concurrency control waiting count exceed max waiting count will be returned. The error codes are:

  • RDS MySQL 8.0: ERROR 7534 (HY000).

  • PolarDB MySQL 5.7: ERROR 3277 (HY000).

  • PolarDB MySQL 8.0: ERROR 7533 (HY000).

  If the ccl_max_waiting_count parameter is set to the default value 0, all throttled SQL statements will remain in the Concurrency control waiting state without returning an error. When throttling through DAS, if this parameter is 0, DAS will set it to the DAS default value (currently 10). If the user has set it to a value greater than 0, DAS will not change the parameter and will use the user's setting.

8. Click Submit to complete the creation.

   After the SQL throttling rule is created, you can view the rule information on the Running tab. The parameters in the list are as follows:

   Note

   The parameters in the list may vary slightly depending on the database engine and throttling mode.

   Parameter	Description
   Throttling Mode	The mode you selected.
   Throttling Rule	Keyword Throttling: The throttling keyword configuration information. SQL Template Throttling: The template ID information corresponding to the throttling sample. Running Time Throttling: The execution time threshold/number of throttled template SQL statements configured.
   Maximum Concurrency	The maximum concurrency of SQL statements.
   Maximum Waiting Count	The maximum waiting count configured in the throttling rule. Note This parameter is displayed when the database instance is RDS PostgreSQL and Throttling Mode is set to SQL Template Throttling.
   Throttling Duration (Minutes)	The effective time of SQL throttling.
   Start Time	The time when the throttling rule was configured (effective time).
   Remaining Time	The remaining time before the throttling rule expires.
   Throttling SQL Sample	The throttling SQL sample configuration. Note This parameter is displayed when Throttling Mode is set to SQL Template Throttling.
   Throttling Template ID	The template ID corresponding to the throttling SQL sample. Note This parameter is displayed when Throttling Mode is set to SQL Template Throttling.
   Status	Rules that are running are in the enabled state.
   Database	The database for SQL throttling. Note This parameter is displayed when Throttling Mode is set to SQL Template Throttling.
   Search Path	The search path for the throttled SQL statements. Note This parameter is displayed when the database instance is RDS PostgreSQL and Throttling Mode is set to SQL Template Throttling.
   Matched SQL Count	The number of SQL statements matched under the throttling rule configuration. Note This parameter is displayed when Throttling Mode is set to SQL Template Throttling.
   Waiting SQL Count	The number of SQL statements currently waiting under the throttling rule configuration. Note This parameter is displayed when Throttling Mode is set to SQL Template Throttling.
   Operation	The Disable or Modify buttons for the throttling rule.

References

Automatic SQL throttling

Related API operations