Memory Management
Replicator Servers read the distribution queue into memory. If there is a high volume of replication activity, there is potential for the queue to become so large that the Replicator Server cannot efficiently handle it. To prevent this from occurring, Ingres Replicator provides the Transaction Break Limit (-QBT) and the Queue Read Limit (-QBM) flags, which define how many queue records can be read into memory.
The Replicator Server reads rows from the distribution queue up to the value of the -QBT flag (4000 rows by default) and begins looking for a logical break in the transaction to stop reading and start propagation. The maximum number of rows a Replicator Server can read into memory from the distribution queue is the value of the -QBM flag (5000 rows by default).
Important! If the number of rows in a single transaction exceeds the value of the -QBM flag, the Replicator Server writes an appropriate error message to the replicat.log file and shut down. You need to increase the value of the -QBM flag and restart the Replicator Server.
The settings you choose for -QBM or -QBT depend on your operating system environment and the nature of your database transactions. If you find you are running out of virtual memory or you are paging excessively in the operating system, use values lower than the default. If you are reaching the default limits and are not having memory problems, increase the default.
Note: Once memory is acquired, a Replicator Server continually re-uses it. If a Replicator Server acquires too much memory, dynamically resetting the -QBT or ‑QBM values has no effect. To change memory usage, a Replicator Server must be shut down and restarted.