Enterprise Replication Enhancements

The following new features enhance the extensibility, usability, or performance of the Enterprise Replication facility of Dynamic Server.

All Enterprise Replication features are documented in the IBM Informix Dynamic Server Enterprise Replication Guide.

Enterprise Replication Security

Enterprise Replication supports the same levels of network encryption available for client/server communications. Encryption is implemented in Enterprise Replication with the encryption configuration parameters listed in New and Altered Configuration Parameters.

Support for ROW and Collection Data types

Enterprise Replication can now replicate the following data types:

• Named and unnamed ROW data types
• Collection data types: LIST, MULTISET, and SET

Faster Queue Recovery

The addition of a table with replicate information to the transaction records and row data tables reduces transaction processing time.

Replication During Queue Recovery

Users can connect to a database server during queue recovery; transactions are added to the queue. However, if the volume of transactions during queue recovery is so large that the logical log is in danger of being overwritten, replication is blocked.

Large Transactions Support

Enterprise Replication automatically spools large transactions to disk instead of holding them in memory. Rows from spooled transactions are paged in and out of memory as needed. Enterprise Replication can replicate transactions up to 4 TB in size.

Improved Availability with HDR

You can use High-Availability Data Replication (HDR) on critical database servers in an Enterprise Replication system to provide identical backup database servers. (Dynamic Server releases earlier than Version 9.4 could support either Enterprise Replication or HDR, but both could not run concurrently.)

Dynamic Log File

Enterprise Replication can request the database server to add a new dynamic log file if replication enters DDRBLOCK mode.

The new CDR_MAX_DYNAMIC_LOGS configuration parameter specifies the number of dynamic log file requests that Enterprise Replication can make in one server session.

New Commands

The new brief option for the cdr list replicate command displays a summary of participants for all replicates

The new cdr remove command removes Enterprise Replication from an HDR server.

New and Altered Configuration Parameters

Enterprise Replication has the following new configuration parameters:

• CDR_DBSPACE specifies the dbspace of the syscdr table.
• CDR_ENV sets Enterprise Replication environment variables.
• CDR_MAX_DYNAMIC_LOGS specifies the number of dynamic log file requests that Enterprise Replication can make in one server session.
• ENCRYPT_CDR to enable and set the level of network encryption.
• 4ENCRYPT_CIPHERS to specify the ciphers to use for encryption.
• ENCRYPT_MAC to specify the level of message authentication coding to use.
• ENCRYPT_MACFILE to specify MAC key files.
• ENCRYPT_SWITCH to define the frequency at which ciphers and secret keys are re-negotiated.

The CDR_QDATA_SBSPACE configuration parameter now allows you to specify up to 32 sbspaces for Enterprise Replication to use for storing spooled row data.

The CDR_QDATA_SBFLAGS configuration parameter is deprecated.

New Environment Variables

The CDR_LOGDELTA environment variable determines when the send and receive queues are spooled to disk.

The CDR_PERFLOG environment variable enables queue tracing.

The CDR_ROUTER environment variable disables intermediate acknowledgements of transactions in hierarchical topologies.

The CDR_RMSCALEFACT environment variable sets the number of DataSync threads started for each CPU VP.