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 (default value) Columns Defaults to 1017 and can be adjusted up to 4096 Indexes Defaults to 64 and can be adjusted up to 512 Rows unlimited Size unlimited Partitions 8192
Limitation on a single row Type Upper limit (default value) Size Defaults to 6 MiB and can be adjusted to 120 MiB
You can adjust the size limit via the txn-entry-size-limit
Limitation on a single column Type Upper limit (default value) Size Defaults to 6 MiB and can be adjusted to 120 MiB
You can adjust the size limit via the txn-entry-size-limit
Limitations on data types Type Upper limit CHAR 256 characters BINARY 256 characters VARBINARY 65535 characters VARCHAR 16383 characters TEXT Defaults to 6 MiB and can be adjusted to 120 MiB BLOB Defaults to 6 MiB and can be adjusted to 120 MiB
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 upper limit is 5000.
You can modify the limit via the stmt-count-limit
Limitations on TiKV version In your cluster, if the version of the TiDB component is v6.2.0 or later, the version of TiKV must be v6.2.0 or later.