Case 2: Different map instances run at same time or sequentially based on source and target settings

Unique log file names and unique work file names do not guarantee map instances will run at the same time. For example, if the same input file is used each time a map runs, and it is updated by a map rule, the resource manager will not let multiple map instances run at the same time because the result of one map instance is dependent on another.

Map instances will run sequentially under the following conditions:

• If a map uses the same file or message as both a source and target
• If a source is the same file each time a map runs and a map rule is used to update it
• If a target is a file and that file is appended

If any of the previous conditions apply, you will not see two instances of the same map running at the same time.