The DB2ROUND= parameter lets you control which RMF interval a record falls into. DB2 usually fires off its interval-based SMF records (the type 100s) with a time that is slightly after a minute starts. With very short RMF interval lengths (e.g., 1 minute), this can make data arrive in the “wrong” interval.
DBROUND=0 is the default and will subtract 5 seconds from a time to ensure it appears in the correct RMF interval. For example, a record with a time of 18:15:02.36 will be altered to 18:14:57.36.
DB2ROUND=1 means times will be “floored” down to the minute in which they were written. For example, a record with a time of 09:17:02.36 will be altered to 09:17:00.00.
DB2ROUND=2 will round a time down unless the time is 59 seconds or more into a minute when it will round up. For example, a time of 09:17:59.16 will round up to 09:18:00.00.
DBROUND=3 will not touch the time and pass it on exactly as-is.
The DB2TIME= parameter can be used to select the timestamp for a DB2 transaction. You can associate a transaction with:
The time it started (S), or
The time it ended (E), or
The time that the SMF record was written by DB2 (D) - this is the default