插入数量超过20时Oracle数据库更改通知不起作用

Question

public class Register {

    @Autowired
    private DataSource dataSource;

    @Autowired
    private DCNListener listener;


    private OracleConnection oracleConnection = null;
    private DatabaseChangeRegistration dcr = null;
    private Statement statement = null;
    private ResultSet rs = null;


    @PostConstruct
    public void init() {
        this.register();
    }


    private void register() {


        Properties props = new Properties();
        props.put(OracleConnection.DCN_NOTIFY_ROWIDS, "true");
        props.setProperty(OracleConnection.DCN_IGNORE_DELETEOP, "true");
        props.setProperty(OracleConnection.DCN_IGNORE_UPDATEOP, "true");

        try {

            oracleConnection = (OracleConnection) dataSource.getConnection();

            dcr = oracleConnection.registerDatabaseChangeNotification(props);
            statement = oracleConnection.createStatement();
            ((OracleStatement) statement).setDatabaseChangeRegistration(dcr);

            rs = statement.executeQuery(listenerQuery);

            while (rs.next()) {

            }

            dcr.addListener(listener);

            String[] tableNames = dcr.getTables();
            Arrays.stream(tableNames)
                    .forEach(i -> log.debug("Table {}" + " registered.", i));

        } catch (SQLException e) {
            e.printStackTrace();
            close();
        }

    }
}

My Listener:

public class DCNListener implements DatabaseChangeListener {

    @Override
    public void onDatabaseChangeNotification(DatabaseChangeEvent databaseChangeEvent) {

        TableChangeDescription[] tableChanges = databaseChangeEvent.getTableChangeDescription();

        for (TableChangeDescription tableChange : tableChanges) {

            RowChangeDescription[] rcds = tableChange.getRowChangeDescription();

            for (RowChangeDescription rcd : rcds) {

                RowOperation op = rcd.getRowOperation();
                String rowId = rcd.getRowid().stringValue();

                switch (op) {

                    case INSERT:
                        //process
                        break;

                    case UPDATE:
                        //do nothing
                        break;

                    case DELETE:
                       //do nothing
                        break;

                    default:
                        //do nothing
                }

            }

        }
    }
}

In my Spring boot application, I have an Oracle DCN Register class that listens for INSERTS in an event table of my database. I am listening for insertion new records.

In this Event table, I have different types of events that my application supports, lets say EventA and EventB.

The application gui allows you to upload in bulk these type of events which translate into INSERT into the oracle database table I am listening to.

For one of the event types, my application is not capturing the INSERT ONLY when it is 20 or more events uploaded in bulk, but for the other event type, I do not experience this problem.

So lets say user inserts eventA any number < 20, my application captures the inserts. But if the number of eventA inserts exceeds 20, it does not capture.

This is not the case for eventB which works smoothly. I'd like to understand if I'm missing anything in term of registration and anything I can look out for maybe in the database or what the issue could be here?

Answer 1

You should also look for the ALL_ROWS event from:

EnumSet<TableChangeDescription.TableOperation> tableOps = tableChange.getTableOperations();
if(tableOps.contains(TableChangeDescription.TableOperation.ALL_ROWS)){
  // Invalidate the cache
}

Quote fromt the JavaDoc:

The ALL_ROWS event is sent when the table is completely invalidated and row level information isn't available. If the DCN_NOTIFY_ROWIDS option hasn't been turned on during registration, then all events will have this OPERATION_ALL_ROWS flag on. It can also happen in situations where too many rows have changed and it would be too expensive for the server to send the list of them.

https://docs.oracle.com/en/database/oracle/oracle-database/12.2/jajdb/oracle/jdbc/dcn/TableChangeDescription.TableOperation.html#ALL_ROWS