Querying the Synchronization Progress

Prerequisites

You have logged in to the DRS console.

Procedure

1. On the Data Synchronization Management page, click the target synchronization task name in the Task Name/ID column.
2. On the displayed page, click Synchronization Progress to view table synchronization progress.
   • When a full synchronization is complete, the progress reaches 100%.
   • After the full synchronization is complete, the incremental synchronization starts. You can view the incremental synchronization delay on the Synchronization Progress tab.
   • You can also view the incremental synchronization delay on the Data Synchronization Management page. When the incremental synchronization delay exceeds the preset or default threshold, the value of the incremental synchronization delay is displayed in red in the task list.
   • When the delay is 0s, the data in the source and destination databases is synchronized in real time.
   

   "Delay" refers to the delay from when the transaction was submitted to the source database to when it is synchronized to the destination database and executed.

   Transactions are synchronized as follows:

   1. Data is extracted from the source database.
   2. The data is transmitted over the network.
   3. DRS parses the source logs.
   4. The transaction is executed on the destination database.

   If the delay is 0, the source database is consistent with the destination database, and no new transactions need to be synchronized.

   

   Frequent DDL operations, ultra-large transactions, and network problems may result in excessive synchronization delay.

3. In the MySQL synchronization scenario, you can view the information about the source position and consumed position on the Synchronization Progress tab.
   

   The displayed position information is updated every 10 seconds.

   Figure 1 Synchronization position information
   

4. In synchronization with Oracle serving as the source, MySQL to Kafka synchronization, and GaussDB to Kafka synchronization, on the Synchronization Progress tab, view the number of DML operations (Insert, Delete, and Update) performed on the source database. In the upper right corner of the Task Monitoring list, refresh the list and view the latest monitoring data.
   Figure 2 Task monitoring
   
   

   1. After you perform the DML operation on the source database and run the commit command to make the operation take effect, the operation data can be displayed in the Task Monitoring list.
   2. DRS collects statistics on the number of operations based on redo logs.
   3. For tables with large object (LOB) data type columns, Oracle records more information in redo logs than the information generated by the actual operations that is performed. The INSERT and UPDATE operations are first performed on non-LOB columns and then on LOB columns. DRS collects statistics only from the redo logs, so the number of recorded operations may be inconsistent with the actual number of changed rows according to operation audit.
   4. The Oracle MERGE statement can be converted into INSERT, UPDATE, and DELETE operations in the redo log. Thus, the number of rows changed by the MERGE statement are increased because the INSERT, UPDATE, and DELETE operations are separately recorded in the redo log.

5. In the Oracle to GaussDB primary/standby or distributed synchronization scenario, search for the detailed synchronization object information on the Synchronization Progress tab. The keywords for searching synchronization objects are case sensitive.
   Figure 3 Synchronization details