Using batch synchronization for LOB objects v7

When synchronizing tables with LOB-type columns (with BLOB, CLOB, BYTEA objects, and so on), Replication Server copies the rows by grouping 5 rows in a batch by default. This is to avoid causing out-of-memory errors when a LOB column has a large amount of data. You can customize the batch size to increase or decrease the number of rows copied in a batch.

To improve the performance of synchronization procedures, reduce network roundtrips, and speed up data replication, you can copy rows with LOBs in larger batches. Configure larger batches only if the instance hosting the replication server has enough memory.

You can configure the replication of up to 1000 rows per batch.

Enabling batch operations on LOBs

Prerequisites

Your instances must use a Replication Server version that includes this feature. See Release notes for an overview of the available release versions and the included enhancements.

Altering the number of rows per batch

1. In the publication or primary server, open the xdb_pubserver.conf file.

   See Installation details to find out where this file is stored according to your operating system.

2. In the xdb_pubserver.conf file, look for the syncLOBBatchSize value.

3. Adapt the syncLOBBatchSize value according to your needs. If not uncommented already, uncomment the line to override the default. This example sets Replication Server to synchronize 150 rows with LOB data per batch:

   → WrapCopy

   syncLOBBatchSize=150

4. Reload the configuration file.

   Now, each time you perform a synchronization, the Replication Server copies 150 rows with LOB objects per network roundtrip.