This project is up for adoption - Feel free to fork it.
This is an Informix CDC client that allows you to capture and unserialize changes on one or multiple tables of the database
It implements methods described by IBM in this sections: https://www.ibm.com/support/knowledgecenter/en/SSGU8G_12.1.0/com.ibm.cdc.doc/ids_cdc_057.htm
This project is still a work in progress, some data types are not correctly unserialized.
| Data type | Status | Comment |
|---|---|---|
| CHAR | Supported | |
| SMALLINT | Supported | |
| INTEGER | Supported | |
| FLOAT | Supported | |
| SMALLFLOAT | Supported | |
| DECIMAL | Supported | |
| SERIAL | Supported | Unit test fails and needs to be adapted |
| DATE | Not supported | |
| MONEY | Supported | |
| DATETIME | Not supported | Supported up to "YEAR TO SECONDS" precision |
| VARCHAR | Supported | |
| NCHAR | Supported | |
| NVARCHAR | Supported | |
| INT8 | Not supported | |
| SERIAL8 | Supported | Unit test fails and needs to be adapted |
| LVARCHAR | Supported | |
| BOOLEAN | Supported | |
| BIGINT | Not supported |
A unit test is provided to test the various data types.
Use the provided docker-compose file to launch an Informix database instance, and use this command to create the CDC schema before running the test.
dbaccess -e informix < $INFORMIXDIR/etc/syscdcv1.sqlSee Unit tests for detailed use.
// 1 - Create the CDCConnection
onnectionDetails connectionDetails = new CDCConnectionDetails(connectionString);
connectionDetails.setUsername(username);
connectionDetails.setPassword(password);
connectionDetails.setInformixServer(informixServer);
connectionDetails.setMaxRecordsPerReturn(maxRecordsPerReturn);
connectionDetails.setCdcTimeout(timeout);
connectionDetails.setInterfaceMajorVersion(1);
connectionDetails.setInterfaceMinorVersion(1);
connectionDetails.setDebugging(false);
cdcConnection = new CDCConnection(connectionDetails);
cdcConnection.connect();
// 2 - Enable capture on the table
cdcConnection.enableCapture(catalog + ":" + schema + "." + table, columnNames);
// 3 - Wait for changes
boolean exit = false;
do {
log.debug("Reading...");
cdcRecords = cdcConnection.readData();
if (!cdcRecords.isEmpty()) {
log.debug("Got " + cdcRecords.size() + " record(s) (" + cdcConnection.getConnectionDetails().getMaxRecordsPerReturn() + "max)");
}
for (CDCRecord cdcRecord : cdcRecords) {
// Process record (see @4)
processRecord(cdcRecord);
// Exit if no change has been captured (timeout)
if (cdcRecord.isTimeoutRecord()) { exit = true; }
}
} while (!exit);
// 4 - Process records
private void processRecord(CDCRecord record) {
// Ignore timeout records
if (!record.isTimeoutRecord()) {
log.debug("{}", record);
}
// A single Metadata record is fired when starting capture, save this records for later, they'll be used for unserialization
if (record.isMetadataRecord()) {
CDCMetadataRecord cdcMetadataRecord = (CDCMetadataRecord) record;
metadataRecords.put(cdcMetadataRecord.getUserData(), cdcMetadataRecord);
}
// An operationnal record is fired when an INSERT/UPDATE/DELETE operation is done
if (record.isOperationalRecord()) {
CDCOperationRecord cdcOperationRecord = (CDCOperationRecord) record;
CDCMetadataRecord cdcMetadataRecord = metadataRecords.get(cdcOperationRecord.getUserData());
// Parse the payload data for the operation record to get the column values
Map<String, Object> cdcOperationRecordPayload = CDCMessageFactory.parseCDCRecordPayload(cdcOperationRecord, cdcMetadataRecord);
log.info("{}", cdcOperationRecordPayload);
}
}Implementation for the CDC client is loosely based on sources published by pushtechnology: https://www.programcreek.com/java-api-examples/index.php?source_dir=adapters-master/cdc/src/com/pushtechnology/diffusion/api/adapters/cdc/CDCConnection.java#
Implementation for the data unserializing is adapted from IBM's C sample: https://www.ibm.com/support/knowledgecenter/fr/SSGU8G_11.50.0/com.ibm.cdc.doc/ids_cdc_060.htm