To ensure the stability and security of clusters, AnalyticDB for MySQL is subject to the limits that are described in the following tables.

Naming limits

The following table describes the naming limits for AnalyticDB for MySQL Data Lakehouse Edition (V3.0) and Data Warehouse Edition (V3.0).
ObjectNaming convention
Database name
  • The name can be up to 64 characters in length.
  • The name must start with a lowercase letter.
  • The name can contain letters, digits, and underscores (_).
  • The name cannot contain consecutive underscores (_).
  • The name cannot be the same as that of the built-in analyticdb database.
Table name
  • The name must be 1 to 127 characters in length.
  • The name must start with a letter or underscore (_).
  • The name can contain letters, digits, and underscores (_).
  • The name cannot contain single quotation marks ('), double quotation marks (''), exclamation points (!), or spaces.
  • The name cannot be an SQL reserved keyword.
Column name
  • The name must be 1 to 127 characters in length.
  • The name must start with a letter or underscore (_).
  • The name can contain letters, digits, and underscores (_).
  • The name cannot contain single quotation marks ('), double quotation marks (''), exclamation points (!), or spaces.
  • The name cannot be an SQL reserved keyword.
Index nameThe name can be up to 64 characters in length.
Account name
  • The name must be 2 to 16 characters in length.
  • The name must start with a lowercase letter.
  • The name must end with a lowercase letter or a digit.
  • The name can contain lowercase letters, digits, and underscores (_).
Password
  • The password must be 8 to 32 characters in length.
  • The password must contain at least three of the following character types: uppercase letters, lowercase letters, digits, and special characters.
  • The password can contain the following special characters: ! @ # ￥ % ^ & * ( ) _ + - =

Quota limits

The following table describes the quota limits for AnalyticDB for MySQL Data Lakehouse Edition (V3.0) and Data Warehouse Edition (V3.0).

LimitsDefault valueDescription
Maximum number of clusters that can be purchased within each Alibaba Cloud account64None
Maximum number of databases that can be created for each cluster2048None
Total number of scale-in, scale-out, upgrade, and downgrade operations on each cluster per day12None
Maximum disk usage for a cluster in reserved mode for Cluster Edition80%If the disk usage of a cluster exceeds the threshold, the system sends an alert notification. Each contact can receive up to four alert notifications for disk usage every day.
90%If the disk usage of a cluster exceeds the threshold, the system sends an alert notification, locks the cluster, and denies data write requests. Each contact can receive up to four alert notifications for disk usage every day.
Maximum amount of hot data for an elastic I/O unit (EIU) within a cluster in elastic mode for Cluster Edition4 TBIf the amount of hot data for an EIU exceeds 4 TB, the system locks the cluster and denies data write requests. For information about how to resolve this issue, see What do I do if a cluster is locked?
Maximum number of standard accounts that can be created for each cluster256None
Maximum number of connections that can be established to each cluster5000None
Maximum number of IP address whitelists that can be configured for each cluster50None
Maximum number of IP addresses that can be added to each whitelist1000None
Maximum number of IP addresses that can be added to whitelists in each cluster25000None
Maximum number of partitions in each cluster102400None
Maximum number of tables that can be created for each cluster that has 1 to 20 node groups in reserved mode for Cluster Edition80000/(Number of shards/Number of node groups)
  • This value can be increased by adding more node groups. For more information, see Change cluster configurations (Data Warehouse Edition).
  • The following SQL statement can be used to query the number of shards: SELECT count(1) FROM information_schema.kepler_meta_shards;
  • In the formula, Number of shards/Number of node groups must be rounded up.
Maximum number of internal tables that can be created for each cluster in elastic mode for Cluster Edition[80000/(Number of shards/Number of EIUs)] × 2
  • This value can be increased by adding more EIUs. For more information, see Use EIUs to scale up storage resources.
  • The following SQL statement can be used to query the number of shards: SELECT count(1) FROM information_schema.kepler_meta_shards;
  • In the formula, Number of shards/Number of EIUs must be rounded up.
Maximum number of external tables that can be created for each cluster in elastic mode for Cluster Edition500000None
Maximum number of columns in each table4096None
Maximum length of comments in each table1024 charactersNone
Maximum length of comments in each column1024 charactersNone
Maximum length of each column16 MBNone
Maximum length of data that can be written to each row16 MBNone
Default length of each column127 charactersNone
Maximum number of columns that can be contained in each query1024None
Maximum number of items that can be specified in each WHERE clause256None
Maximum number of conditions that can be specified in each IN operator2000The following SQL statement can be used to modify this value based on your business requirements: SET adb_config MAX_IN_ITEMS_COUNT=3000;.

A larger value makes an SQL query more complex and may affect query performance.

Timeout limits

The following table describes the timeout limits for AnalyticDB for MySQL Data Lakehouse Edition (V3.0) and Data Warehouse Edition (V3.0).

OperationTimeout period (unit: milliseconds)Description
Create a cluster600,000None
Delete a cluster300,000None
Scale up a cluster600,000None
Create a database10,000None
Delete a database10,000None
Create a table or view10,000None
Delete a table or view10,000None
Truncate a table60,000None
Add a column10,000None
Remove a column60,000None
Update a column60,000None
Perform a single query1,800,000The timeout period for a query. When a query times out, the system ends the query.
You can modify the timeout period for a query by using the following parameter and hint:
  • Parameter: QUERY_TIMEOUT
  • Hint: query_timeout
Note The system checks timeout queries every 1,000 milliseconds. Therefore, the maximum execution duration of a query must be set to a value greater than 1,000 milliseconds. Otherwise, the query_timeout hint may not take effect.
Insert data300,000None
  • INSERT SELECT FROM
  • INSERT UPDATE FROM
  • INSERT DELETE FROM
24 × 3,600,000The timeout period for an INSERT statement. When an INSERT statement times out, the system ends the statement.
You can modify the timeout period for an INSERT statement by using the following parameter and hint:
  • Parameter: INSERT_SELECT_TIMEOUT
  • Hint: insert_select_timeout