Identifier length limits
MySQL mode
Item Maximum length Cluster name 128 bytes Tenant name 64 bytes Username 64 bytes Database name 128 bytes Table name 64 characters Column name 128 bytes Index name 64 bytes View name 64 bytes Alias 255 bytes Table group name 128 bytes Oracle mode
Item Maximum length Cluster name 128 bytes Tenant name 64 bytes Username 64 bytes Table name 128 bytes Column name 128 bytes Index name 128 bytes View name 128 bytes Alias 255 bytes Object name 128 bytes Table group name 128 bytes
Maximum OBProxy connections
| Item | Upper limit |
|---|---|
| Number of connections per OBProxy | You can specify the client_max_connections parameter of an OBProxy to specify the maximum number of connections of the OBProxy. The default value is 8192. You can increase the number of OBProxy nodes or the value of the client_max_connections parameter to increase the maximum number of connections for a cluster.
|
Maximum number of partition replicas
| Item | Upper limit |
|---|---|
| Number of partition replicas per OBServer | No upper limit. Note We recommend that you do not set the number of partition replicas per OBServer to a value greater than 100,000. |
Single-table limits
| Item | Upper limit |
|---|---|
| Row length | 1.5 MB |
| Number of columns | 4,096 |
| Number of indexes | 128 |
| Total number of index columns | 512 |
| Index length | 1.5 MB |
| Total number of primary key columns | 64 |
| Primary key length | 16 KB |
| Number of partitions |
|
Single-column limits
| Item | Upper limit |
|---|---|
| Length of an index column | 262,143 bytes |
| Length of a primary key column | 262,143 bytes |
String type limits
MySQL mode
Type Maximum length CHAR255 bytes VARCHAR65,535 bytes BINARY255 bytes VARBINARY65,535 bytes BLOB65,535 bytes TEXT65,535 bytes Oracle mode
Type Maximum length CHAR2,000 bytes VARCHAR32,767 bytes VARCHAR232,767 bytes NCHAR2,000 bytes NVARCHAR232,767 bytes