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sqldatabaseoracle-databasetalend

Talend's tOracleInput does not read data


My colleague created a project in Talend to read data from Oracle database. I used his project and so I have his Job context with connection parameters to Oracle DB and Talend successfully connects on that computer.

I've created a trivial job which is composed of two components: tOracleInput which should be reading data and tLogRow which should be redirecting output to Talend's terminal.

The problem is that when I start the job - data is not outputted to terminal and instead of row amount outputted per second I see Starting ... status.

Would it be connection issues, inappropriate java version on my computer or something else?


Solution

  • Starting... status means that the query is being executed. Usually it takes a few seconds to execute a simple query against the database. This is because of the Oracle database behavior that it starts to return the data without completing a full table scan. To use this feature you can use joins and filters, but not group by / order by.

    On the other hand if you're using a view or executing a complex query, or just simply use DISTINCT it could happen that the query execution takes a few minutes. This is because the oracle database generates the ResultSet on the database side before returning the records.