TiDB Limitations
This document describes general usage limits in TiDB, including the maximum length of identifiers and the maximum number of supported databases, tables, indexes, partitioned tables, and sequences.
Identifier Length Limits
| Identifier type |
Maximum length (number of allowed characters) |
| Database |
64 |
| Table |
64 |
| Column |
64 |
| Index |
64 |
| View |
64 |
| Sequence |
64 |
Limits on the Total Number of Databases, Tables, Views, and Connections
| Identifier type |
Maximum number |
| Databases |
Unlimited |
| Tables |
Unlimited |
| Views |
Unlimited |
| Connections |
Unlimited |
Single Database Limits
| Type |
Upper limit |
| Tables |
Unlimited |
Single Table Limits
| Type |
Upper limit (default) |
| Columns |
The default is 1017 and can be adjusted up to 4096. |
| Indexes |
The default is 64 and can be adjusted up to 512. |
| Rows |
Unlimited |
| Size |
Unlimited |
| Partitions |
8192 |
- The upper limit for
Columns can be changed with table-column-count-limit.
- The upper limit for
Indexes can be changed with index-limit.
Single Row Limits
| Type |
Upper limit |
| Size |
6MB |
You can adjust the size limit with the txn-entry-size-limit configuration item. |
|
Single Column Limits
| Type |
Upper limit |
| Size |
6MB |
String Type Limits
| Type |
Upper limit |
| CHAR |
256 characters |
| BINARY |
256 characters |
| VARBINARY |
65535 characters |
| VARCHAR |
16383 characters |
| TEXT |
6MB |
| BLOB |
6MB |
SQL Statement Limits
| Type |
Upper limit |
| Maximum number of SQL statements in a single transaction |
When optimistic transactions and transaction retries are used, the upper limit is 5000. |
You can change the limit with the stmt-count-limit configuration item.