diff --git a/TOC.md b/TOC.md index c2f06821fefd2..465043bf2bd83 100644 --- a/TOC.md +++ b/TOC.md @@ -11,6 +11,7 @@ + [Key Features](/key-features.md) + Compatibility + [MySQL Compatibility](/mysql-compatibility.md) + + [TiDB Limitations](/tidb-limitations.md) + Quick Start + [Try Out TiDB](/quick-start-with-tidb.md) + [Learn TiDB SQL](/basic-sql-operations.md) diff --git a/tidb-limitations.md b/tidb-limitations.md new file mode 100644 index 0000000000000..fd8e52b81552e --- /dev/null +++ b/tidb-limitations.md @@ -0,0 +1,74 @@ +--- +title: TiDB Limitations +summary: Learn the usage limitations of TiDB. +category: introduction +--- + +# TiDB Limitations + +This document describes the common usage limitations of TiDB, including the maximum identifier length and the maximum number of supported databases, tables, indexes, partitioned tables, and sequences. + +## Limitations on identifier length + +| Identifier type | Maximum length (number of characters allowed) | +|:---------|:--------------| +| Database | 64 | +| Table | 64 | +| Column | 64 | +| Index | 64 | +| View | 64 | +| Sequence | 64 | + +## Limitations on the total number of databases, tables, views, and connections + +| Identifier type | Maximum number | +|:----------|:----------| +| Databases | unlimited | +| Tables | unlimited | +| Views | unlimited | +| Connections| unlimited| + +## Limitations on a single database + +| Type | Upper limit | +|:----------|:----------| +| Tables | unlimited | + +## Limitations on a single table + +| Type | Upper limit | +|:----------|:----------| +| Columns | 512 | +| Indexes | 64 | +| Rows | unlimited | +| Size | unlimited | +| Partitions | 1024 | + +## Limitation on a single row + +| Type | Upper limit | +|:----------|:----------| +| Size | 6 MB | + +## Limitation on a single column + +| Type | Upper limit | +|:----------|:----------| +| Size | 6 MB | + +## Limitations on string types + +| Type | Upper limit | +|:----------|:----------| +| CHAR | 256 characters | +| BINARY | 256 characters | +| VARBINARY | 65535 characters | +| VARCHAR | 16383 characters | +| TEXT | 6 MB bytes | +| BLOB | 6 MB bytes | + +## Limitations on SQL statements + +| Type | Upper limit | +|:----------|:----------| +| The maximum number of SQL statements in a single transaction | When the optimistic transaction is used and the transaction retry is enabled, the default upper limit is 5000, which can be modified using [`stmt-count-limit`](/tidb-configuration-file.md#stmt-count-limit). |