Striim 3.10.3 documentation

Troubleshooting your Oracle to Kafka application

The following are some issues you might encounter when running your application.

OracleReader does not appear to be capturing data
  1. Verify that the StartSCN value (if specified) is correct.

  2. Verify that the Tables property is correct.

  3. OracleReader will send no data until it has accumulated the number of records specified by the FetchSize value. For testing purposes, it can be helpful to set this to 1 to send each record immediately.

  4. Verify that the transactions are committed. By default, OracleReader sends only committed transactions (since the default for the CommittedTransactions property is True).

  5. In the Striim console, enter mon <OracleReader name>; and look at the Last observed LCR-SCN and Last observed LCR-Timestamp values. Enter the command again: if the values have increased, that means OracleReader is buffering events in its transaction cache, and will write them when the transactions are complete and the FetchSize value has been reached. If most of the events are part of long-running transactions, it will take longer for OracleReader to emit the next set.

KafkaWriter seems slow

To see whether KafkaWriter is keeping up with the output of OracleReader, in the Striim console, enter mon <KafkaWriter name>; and look at the Read Lag value (see Understanding Read Lag values for more information). Wait two minutes and enter the command again. If the value has increased, KafkaWriter is not keeping up with OracleReader. Subtract the first value from the second and make a note of that number.

Create multiple instances of Kafkawriter (see Creating multiple writer instances), then run mon <KafkaWriter name>;, wait two minutes, and run it again. If the value did not increase, KafkaWriter is keeping up with OracleReader. If the value increased but the difference between it and the first value is significantly less than it was with a single KafkaWriter, try using a higher prallelism-factor value.

If the PARALLELIZE option does not improve performance, investigate whether the issue might be in Kafka rather than in Striim, as detailed in Testing KafkaWriter performance.