This topic article describes the general 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 combined. If your business requirements are not met due to the limit,submit a ticket. |
| Length of an instance name | 3~16 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 | 1~255 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 | 0~100000 CU |
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 | 1~255 Bytes | The column name can contain letters, digits, and underscores (_). The name must start with a letter or an underscore (_). |
| Number of columns in a primary key | 1 to 4 | A primary key can contain one to four primary key columns. |
| Size of the value in a primary key column of the STRING type | 1 KB | The size of the value in a primary key column of the STRING type cannot exceed 1 KB. |
| Size of the value in an attribute column of the STRING type | 2 MB | The size of the value in an attribute column of the STRING type 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 | Unlimited | None. |
| Size of a single row | Unlimited | 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) on the metadata of tables | 10 QPS | The QPS on the metadata of tables in an instance cannot exceed 10. For more information about table-level operations. |
| Count of UpdateTable operations for a single table | Unlimited | 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 in the row inserted by one PutRow request | 4 MB | None. |
| Size of data updated by one UpdateRow request | 4 MB | None. |
| Size of data scanned 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. |