Memory Consumption Control

To reduce memory consumption in RTL, Replication Server supports full incremental compilation and allows you to control the size of net-change databases. To reduce memory consumption in HVAR, you can control the size of compilable groups.

Full Incremental Compilation for RTL

Full incremental compilation is only available for RTL. Full incremental compilation improves replication performance for RTL by reducing memory consumption during the processing of large compilable transactions that contain many commands.

Full incremental compilation can compile large transactions containing mixed insert, delete, or update operations. Replication Server uses full incremental compilation to apply a large compilable transaction to the replicate database, using multiple in-memory net-change database instances.

See Replication Server Heterogeneous Replication Guide > Sybase IQ as Replicate Data Server > Sybase IQ Replicate Database Configuration > Memory Consumption Control > Full Incremental Compilation.

Control Net-Change Database Size for RTL

Reduce memory consumption by the net-change database by triggering the net-change database to flush data to the replicate database once the net-change database size reaches a threshold size.

You can control the maximum net-change database size that Replication Server can generate. Once the size reaches the threshold you set, Replication Server stops compiling new commands and transactions into the compiled transaction that Replication Server is building in the net-change database, performs the bulk apply of the compiled group to the replicate database, clears the net-change database, and releases the memory consumed by the net-change database.

See Replication Server Heterogeneous Replication Guide > Sybase IQ as Replicate Data Server > Sybase IQ Replicate Database Configuration > Memory Consumption Control > Net-Change Database Size.

Control the Size of Compilable Groups for HVAR

Reduce memory consumption amd improve performance by setting a threshold for the size of large transactions that can be compiled.

Once the threshold is reached, Replication Server applies the large transaction using the continuous replication mode. Replication Server continues to use HVAR to compile smaller compilable transactions into groups and applies the compiled groups to the replicate database as soon as the group size reaches the threshold you set.

See Replication Server Administration Guide Volume 2 > Performance Tuning > Advanced Services Option > High Volume Adaptive Replication > Memory Consumption Control.