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SDU Ignored By The JDBC Thin Client Connection (Doc ID 2652240.1)

Last updated on OCTOBER 06, 2021

Applies to:

JDBC - Version and later
Information in this document applies to any platform.


There is the need to increase the SDU size of the database connections to 32K (or more) to improve performance of a Java application using JDBC  Thin 18.3.

The database is a single instance multi-tenant database running on a 4 node cluster. GI is and RDBMS is on

The following has been implemented:
- Set DEFAULT_SDU_SIZE=131072 in sqlnet.ora of RDBMS home on all the nodes of the cluster, as well as set DEFAULT_SDU_SIZE=131072 in sqlnet.ora file of GI home.
SCAN and local listeners are restarted on all the nodes of the cluster.

- The sqlnet.ora file is updated on the client and DEFAULT_SDU_SIZE=131072 was added to it, and also (SDU=32768) was added to the TNS entries used by SQL*Plus connections.

- Additionally, the JDBC URL is set to include (SDU=32768) like the following:

From SQL Plus (and Toad), when connecting to SCAN or LOCAL listeners, tracing connections shows that SDU size of 32K is used. 
From SQL Developer (or Java application), when connecting to SCAN listener, the trace shows the connection is using the default 8K of SDU.

JDBC seems to ignore the SDU setting in the connection string.





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