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Connection Option Descriptions : SDU Size

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SDU Size




Specifies the size in bytes of the Session Data Unit (SDU) that the driver requests when connecting to the server. The SDU size is equivalent to the maximum number of bytes in a database protocol packets sent across the network. The setting of this option serves only as a suggestion to the database server. The actual SDU is negotiated with the database server.

Valid Values

is an integer from 512 to 2097152 for Oracle 12c and higher, or, for earlier database versions, an integer from 512 to 32767.


When connecting to the server, the driver requests the specified value to be used as the maximum SDU size. While the specified value is only a suggestion, it affects the actual SDU size that is negotiated with the server.
To optimize performance, set this option based on the size of result sets returned by your application. If your application returns large result sets, set this option to the maximum SDU size configured on the database server. This reduces the total number of round trips required to return data to the client, thus improving performance. If your application returns small result sets, set this option to a size smaller than the maximum to avoid burdening your network with unnecessarily large packets.


*This option is mutually exclusive with the Server Name and TNSNames File connection option. The driver generates an exception if a value is specified for SDU Size in conjunction with either option.




Performance tab

See also

Performance Considerations