During step 5, the connector scans all tables regardless of whitelist / blacklist filtering. For schemas with a large number of tables in proportion to the whitelist / blacklist exclusions can result in significant wait times (approximately 2 sec / table)

Create a schema in an Oracle database and populate it with over 34000 tables: Create an Apache Kafka connector with the following connector config: { "name": "inventory-connector", "config": { "connector.class": "io.debezium.connector.oracle.OracleConnector", "tasks.max": "1", "table.whitelist":"(.)CUSTOMERS,(.)PRODUCTS", "database.server.name": "inventory", "database.hostname": "localhost", "database.port": "1521", "database.user": "c##xstrm", "database.password": "xs", "database.dbname": "ORCLCDB", "database.pdb.name": "ORCLPDB1", "database.out.server.name": "dbzxout", "snapshot.delay.ms": "5000", "database.history.kafka.bootstrap.servers": "localhost:9092", "database.history.kafka.topic": "schema-changes.inventory" } } receive the the following log file: [2020-04-09 05:48:01,809] INFO Metrics registered (io.debezium.pipeline.ChangeEventSourceCoordinator:82) [2020-04-09 05:48:01,809] INFO Context created (io.debezium.pipeline.ChangeEventSourceCoordinator:85) [2020-04-09 05:48:03,026] INFO Snapshot step 1 - Preparing (io.debezium.relational.RelationalSnapshotChangeEventSource:94) [2020-04-09 05:48:03,027] INFO Snapshot step 2 - Determining captured tables (io.debezium.relational.RelationalSnapshotChangeEventSource:105) [2020-04-09 05:48:11,984] INFO Snapshot step 3 - Locking captured tables (io.debezium.relational.RelationalSnapshotChangeEventSource:112) [2020-04-09 05:48:12,113] INFO Snapshot step 4 - Determining snapshot offset (io.debezium.relational.RelationalSnapshotChangeEventSource:118) [2020-04-09 05:48:12,619] INFO Snapshot step 5 - Reading structure of captured tables (io.debezium.relational.RelationalSnapshotChangeEventSource:121) ... A lot of lines removed and 10.25 hours later ... [2020-04-09 16:09:23,240] INFO Snapshot step 6 - Persisting schema history (io.debezium.relational.RelationalSnapshotChangeEventSource:125) [2020-04-09 16:09:48,752] INFO Snapshot step 7 - Snapshotting data (io.debezium.relational.RelationalSnapshotChangeEventSource:137) [2020-04-09 16:09:48,753] INFO Exporting data from table '...Some Table...' (io.debezium.relational.RelationalSnapshotChangeEventSource:280) [2020-04-09 16:09:48,753] INFO For table '...Some Table...' using select statement: 'SELECT * FROM ...Some Table... AS OF SCN 9999999999' (io.debezium.relational.Rel ationalSnapshotChangeEventSource:287) [2020-04-09 16:09:49,618] INFO Finished exporting 23 records for table '...Some Table...'; total duration '00:00:00.864' (io.debezium.relational.RelationalSnapshotChangeEventSource :330) [2020-04-09 16:09:49,632] INFO Snapshot - Final stage (io.debezium.pipeline.source.AbstractSnapshotChangeEventSource:79) [2020-04-09 16:09:50,164] INFO Snapshot ended with SnapshotResult [status=COMPLETED, offset=OracleOffsetContext [scn=10784643213] ] (io.debezium.pipeline.ChangeEventSourceCoordinator:90) [2020-04-09 16:09:50,167] INFO Connected metrics set to 'true' (io.debezium.pipeline.metrics.StreamingChangeEventSourceMetrics:59) [2020-04-09 16:09:50,167] INFO Starting streaming (io.debezium.pipeline.ChangeEventSourceCoordinator:100) Note in the oracle database that a query that is a UNION of two selects: One on all_tables and the other a join between all_indexes and all_ind_columns