Operation Merging and Performance

Control-M performs all copy to file operations (option F) first.

After performing all copy to file operations, Control-M merges all operations performed on a specific FROM class.

After merging operations on specific FROM classes, Control-M merges the operations performed on the SYSOUT as a whole (where the FRM subparameter is set to blank).

Control-M then passes the merged sets of instructions to JES for processing.

The resulting combination of operations can vary depending on whether the operation that was merged with a DO SYSOUT operation is a SYSOUT operation or another DO SYSOUT operation.

Generally, DO SYSOUT operations override, or are performed along with, SYSOUT statements.

The following chart and the accompanying numbered explanations indicate the result of merging multiple DO SYSOUT statements. Note the following points about the chart:

• Operations are indicated by their symbols (F,D,R,C,N), at the top and side of the chart. The operations at the top of the chart represent DO SYSOUT operations. The operations at the side of the chart represent SYSOUT or DO SYSOUT operations.
• Merging and processing operations are grouped, and explained, based on operation type. Groups are delimited by lines, and are numbered (from 1 through 4). Within each group, operations are delimited by periods. Explanations of each group are provided, by number, following the chart.
• The handling of the combination of operations is generally reflected in the chart by a single operation code (such as D) or pair of operation codes, such as FR. In some cases, the operations are merged. This is indicated by the word "merged." In some cases, handling depends on whether the combination consists of both a SYSOUT and a DO SYSOUT statement, or multiple DO SYSOUT statements (that is, without a SYSOUT statement). This is indicated by an asterisk (*). These are all explained in the numbered explanations that follow the chart.

  Figure 214 Effect of Merging Multiple SYSOUT Statements

  

The order of precedence in which Control-M processes and merges operations is as follows:

1. DO SYSOUT=F

   Copy to file operations are performed first (directly by Control-M) for DO SYSOUT statements, regardless of whether FROM class is specified. Other operations are then performed.

2. DO SYSOUT=D (Delete)

   This operation supersedes all other DO SYSOUT operations (except copy to file operations described above). Superseded operations are ignored, that is, they are not performed.

3. DO SYSOUT combinations of R, C and N

   In general, combinations of R, C, and N requests are merged, that is, they are all performed. The exceptional cases indicated in the chart are described below:

   • If multiple C requests come from DO SYSOUT statements, perform only one of the requests. Normally, do not specify this combination.
   • If multiple N requests come from DO SYSOUT statements, perform the request that occurs first.