# of JDBC sessions on Oracle while using Debezium

[Manoj Palaniswamy]

Hello - We are trying to replicate data from Oracle database about 2000 tables and send it to MSSQL using Kafka/Debezium. We are currently testing by creating 1 connector and adding 4 tables  - using table.include.list. On the Oracle side we see total of 8 JDBC sessions and the concern is that if we have say 2000 tables in total, there would be 4000 session on Oracle and the Oracle may be impacted. It may prevent # of sessions or crash. Why is this behavior? If i understand right one connector will establish one JDBC connection only (2 including a heartbeat?). What is the best practice to include 2000 tables and have lesser number of connections on Oracle side? thank you..

[Chris Cranford]

Hi -

The number of connections made to Oracle is not related to the number of tables you have in your `table.include.list`, but rather your configuration and environment.

For the Oracle LogMiner adapter, you will see a minimum of 2 connections plus one connection per Oracle RAC node when using Oracle RAC. For all adapters, you may see additional out of bands temporary connections to read certain metadata from the database that cannot be done while processing the change stream of events. But you should not see an extreme number of JDBC connections and these are not in anyway related to the number of tables you have configured.

Hope that helps.
-cc

On 7/24/25 6:07 AM, Manoj Palaniswamy wrote:

Hello - We are trying to replicate data from Oracle database about 2000 tables and send it to MSSQL using Kafka/Debezium. We are currently testing by creating 1 connector and adding 4 tables  - using table.include.list. On the Oracle side we see total of 8 JDBC sessions and the concern is that if we have say 2000 tables in total, there would be 4000 session on Oracle and the Oracle may be impacted. It may prevent # of sessions or crash. Why is this behavior? If i understand right one connector will establish one JDBC connection only (2 including a heartbeat?). What is the best practice to include 2000 tables and have lesser number of connections on Oracle side? thank you.. --
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