OUTPUT BUFFER field (OUTBUFF subsystem parameter)

The OUTPUT BUFFER field sets the OUTBUFF subsystem parameter, which specifies the size of the output buffer for writing active log data sets.

Acceptable values:
  • OUTPUT BUFFER field: 409600–409600000, 400K–400000K, 1M–390M
  • OUTBUFF subsystem parameter: 400–400000
Default:
  • OUTPUT BUFFER field: 4000K
  • OUTBUFF subsystem parameter: 4000
Update: option 41 on panel DSNTIPB
DSNZPxxx: DSN6LOGP OUTBUFF
OUTPUT BUFFER field
409600–409600000
The size in bytes of the output buffer for writing active log data sets, when specified in the OUTPUT BUFFER field.
400K–400000K
The size in kilobytes of the output buffer for writing active log data sets, when specified in the OUTPUT BUFFER field.
1M–390M
The size in megabytes of the output buffer for writing active log data sets, when specified in the OUTPUT BUFFER field.
OUTBUFF subsystem parameter
400–400000
The size in kilobytes of the output buffer for writing active log data sets, when specified for the OUTBUFF subsystem parameter. Omit K in this context.

The larger the output buffer, the more likely that a log read request can return the required log records without needing I/O operations. This is a particularly important consideration if the Db2 subsystem is to be used with a data replication product that uses IFCID 306. In Db2 12, log buffers are permanently page-fixed. When you estimate real storage usage, you must use the entire size that you specify for the OUTBUFF parameter. To avoid page-fixing more storage than necessary, carefully choose the setting for OUTBUFF.