This topic describes the limits of Tablestore. Table schemas and row sizes can be tailored to improve performance.

Limits on instances

Resource Limit Description
Number of instances created within an Alibaba Cloud account 10

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

Number of tables in an instance 64

The number of data tables and index tables. If your business requirements are not met due to the limit, submit a ticket.

Length of an instance name 3 to 16 bytes The name of an instance can contain letters, digits, and hyphens (-). The name must start with a letter and cannot end with a hyphen (-).

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

Limits on tables

Resource Limit Description
Length of a table name 1 to 255 bytes The name of a table can contain letters, digits, and underscores (_). The name must start with a letter or an underscore (_).
Reserved read capacity units (CUs) and reserved write CUs of a single table 0 to 100000 CUs

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

Number of predefined columns 0 to 32 Predefined columns are non-primary key columns whose names and types are defined when a data table is created. When you create a global secondary index, predefined columns can be used as the indexed columns or attribute columns of the index table. For more information, see Global secondary index.
Notice Predefined columns are not required when you use a search index.

Limits on columns

Resource Limit Description
Length of a column name 1 to 255 bytes The name of a table can contain letters, digits, and underscores (_). The name must start with a letter or an underscore (_).
Number of columns in a primary key One to four A primary key can contain one to four primary key columns.
Size of the value in a STRING primary key column 1 KB The size of the value in a STRING primary key column cannot exceed 1 KB.
Size of the value in a STRING attribute column 2 MB The size of the value in a STRING attribute column cannot exceed 2 MB.
Size of the value in a BINARY primary key column 1 KB The size of the value in a BINARY primary key column cannot exceed 1 KB.
Size of the value in a BINARY attribute column 2 MB The size of the value in a BINARY attribute column cannot exceed 2 MB.

Limits on rows

Resource Limit Description
Number of attribute columns in a single row Tablestore does not impose limits on the number of attribute columns in a single row. None.
Size of a single row Tablestore does not impose limits on the size of a single row. Tablestore does not impose limits on the total size of column names or column values for a row.

Limits on operations

Operation Limit Description
Number of attribute columns written by one request 1,024 During a PutRow, UpdateRow, or BatchWriteRow operation, the number of attribute columns written in a row cannot exceed 1,024.
Number of columns specified in columns_to_get in a read request 0 to 128 The maximum number of columns obtained from a row of data in a read request cannot exceed 128.
Queries per second (QPS) at the table level 10 QPS The QPS for tables in an instance cannot exceed 10. For more information about table-level operations, see the "Table operations" section in OperationsSummary.
Count of UpdateTable operations for a single table Tablestore does not impose limits on the count of UpdateTable operations for a single table. The limit on the count of UpdateTable operations for a single table follows the limit on the frequency of adjustment for a single table.
Frequency of calling the UpdateTable operation for a single table Once every 2 minutes The reserved read or write throughput for a single table can be adjusted once every two minutes at most.
Number of rows read by one BatchGetRow request 100 None.
Number of rows written by one BatchWriteRow request 200 None.
Size of data written by one BatchWriteRow request 4 MB None.
Size of data scanned at a time by one GetRange request 5,000 rows or 4 MB The size of data scanned at a time by one GetRange request cannot exceed 5,000 rows or 4 MB. When one of the limits is exceeded, data that exceeds the limit is truncated at the row level. The primary key information of the next row of data is returned.
Data size of an HTTP request body 5 MB None.
Number of filters in one read request 10 None.