Tablestore:Tablestore limits

Item

Limit

Description

Number of Instances

10

If your business requirements are not met due to the limit, submit a ticket.

Instance name

Unique within a region

Instance naming conventions:

• The name must be 3 to 16 characters in length and can contain letters, digits, and hyphen (-). The name is not case-sensitive.

• The name must start with a letter and cannot end with a hyphen (-).

• The name cannot contain the following words: ali, ay, ots, taobao, or admin.

Number of tables in an instance

64

Item

Limit

Description

Name of a data table

Unique within an instance

Naming conventions for data tables:

• The name must be 1 to 255 bytes in length and can contain letters, digits, and underscores (_). The name is case-sensitive.

• The name must start with a letter or an underscore (_).

Number of primary key columns

1~4

The first primary key column is the partition key.

Data types of primary key columns

String, Integer, and Binary

• String: a UTF-8-encoded string that does not exceed 1 KB in length.

• Integer: a 64-bit signed integer that is 8 bytes in length.

• Binary: binary data that does not exceed 1 KB in length.

Number of attribute columns

None

Tablestore does not impose a limit on the number of attribute columns. If you attempt to read a row in which an excessive number of attribute columns are included, such as hundreds of thousands of attribute columns, you may fail to read the row due to timeout. In this case, you must specify the attribute columns that you want to read or read data by page. We recommend that you specify up to 10,000 attribute columns.

Data types of attribute columns

String, Integer, Double, Boolean, and Binary

• String: a UTF-8-encoded string that does not exceed 2 MB in length.

• Integer: a 64-bit signed integer that is 8 bytes in length.

• Double: a 64-bit Double value that is 8 bytes in length.

• Boolean: True or False that is 1 byte in length.

• Binary: binary data that does not exceed 2 MB in length.

Number of predefined columns

0~32

Predefined columns are non-primary key columns whose names and types are defined when a data table is created. Predefined columns can be used as the fields of a secondary index that is created for the data table.

Item

Limit

Description

Name of a time series table

Unique within an instance

Naming conventions for a time series table:

• The name must be 1 to 128 characters in length and can contain letters, digits, and underscores (_). The name is case-sensitive.

• The name must start with a letter or an underscore (_).

Item

Limit

Description

Number of search indexes

None

We recommend that you create only one search index that contains all fields that you want to retrieve.

Number of index fields

1000

None

Number of rows

100 billion

If your business requirements are not met due to the limit, submit a ticket.

Total size

100 TB

If your business requirements are not met due to the limit, submit a ticket.

Read or write rate

50,000 rows/s

• The first time data is written or when a large volume of data is written in a short period of time, Tablestore balances loads within a few minutes.

• The maximum rate of indexing for Text fields is limited to 10,000 rows/s because the process consumes a large number of CPU resources for tokenization.

If your business requirements are not met due to the limit, submit a ticket.

Synchronization latency

3s

• In most cases, the synchronization latency is within 3 seconds.

• Up to 1 minute is required to initialize a new index.

Max versions

Not supported

None

Item

Limit

Description

Number of secondary indexes

5

If your business requirements are not met due to the limit, submit a ticket.

Number of index fields

36

• The primary key of a secondary index consists of index columns and all primary key columns of the data table for which the secondary index is created. The primary key consists of up to eight columns, among which up to four columns are index columns. Index columns can be the primary key columns or predefined columns of the data table.

• A secondary index can contain up to 32 attribute columns, which are the predefined columns of the data table.

Max versions

Not supported

None

Item

Limit

Description

Mapping table names and column names

Cannot be the same as a reserved word or keyword

Naming conventions for a mapping table and a column in a mapping table:

• The name must be 1 to 255 bytes in length and can contain letters, digits, and underscores (_).

• The name must start with a letter or an underscore (_).

• The name must be different from the reserved words and keywords in SQL. For more information, see Reserved words and keywords.

Execution duration of a single SQL statement

30 s

The execution duration of a single SQL statement is related to the complexity of the SQL statement and the amount of data in the table. The maximum duration is 30 seconds. If the maximum duration is exceeded, the system returns an error.

Amount of data for a single scan

128 MB or 100,000 rows

The maximum number of rows for a single scan is 100,000 or the maximum amount of data for a single scan is 128 MB. If the upper limit is exceeded, the system returns an error.