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HiRDB Datareplicator Version 8 Description, User's Guide and Operator's Guide
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Datareplicator starts a transmission process for each destination. If there are many destinations, there will be many transmission processes and a memory shortage might occur in the source system, or queue file I/O operations might slow down. To prevent this, you can control the transmission processes to be started so that all transmission processing is executed within a specified number of transmission processes.
To control the number of transmission processes, specify sendmst in the sendcontrol operand in the extraction system definition. When you make this specification, a transmission master process is generated between the node master process and the transmission processes. This transmission master process controls the startup, termination, and transmission schedule of the transmission processes.
The following figure provides an overview of transmission process control. This example uses two transmission processes to achieve transmission to three destinations.
Figure 3-17 Overview of transmission process control
![[Figure]](FIGURE/RZ03S170.GIF)
The transmission master process reads update information from the extraction information queue file before the transmission interval is reached and creates valid transaction management information for each destination. If the transmission master process successfully creates valid transaction management information within the transmission interval, it issues transmission requests to the transmission processes. The transmission master process then schedules the active transmission processes within the constraints of the maximum number of active processes.
When the number of transmission processes is controlled, the function of a transmission process varies as follows:
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