Compare and Refresh

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Compare or Synchronize Heterogeneous Data in Realtime

HVR Compare and Refresh allows synchronization of business data in different databases. This can be used independently for fast and heterogeneous batch data loading. And it can also complement database replication (capturing changes and applying them to another database) as an indispensable operator utility. Database refresh is when two databases need to be brought into sync with each other. Database compare allows the operator to see whether two large databases are identical or not.

Bulk Compare HVR performs checksums on each of the replicated tables and only compares these checksums. This allows big databases to be compared without any network traffic.	Row-wise Compare HVR reads from one database and compares each row with the corresponding row in the other database. As this is done it calculates an SQL script describing the minimum insert, update and deletes statements needed to synchronize the table. If the databases are on different machines then the data is automatically compressed and uncompressed as it passes through the network pipe.
Bulk Refresh HVR reads the data from all the tables in one database and bulk-loads it into the target database. If the databases are on different machines then the data is automatically compressed and uncompressed as it passes through the network pipe. Table indexes are then reset.	Row-wise Refresh Row-wise refresh is the same as row-wise compare, except the resulting SQL statements are applied directly to the target database in order to re-synchronize the tables.

Speed and Scalability

HVR Compare and Refresh are enhanced using threads for parallel data streams. HVR groups the tables to be processed into groups of similar size by checking the DBMS catalog information about the size of each table, which ensures good load-balancing across the sessions. All flavors of refresh and compare are very fast and very flexible.