Auto Match and Merge batch jobs execute a continual cycle of a Match job, followed by an Automerge job, until there are no more records to match, or until the maximum number of records for manual consolidation limit is reached.
The match batch size parameter controls the number of records per cycle that this process goes through to finish the match and merge cycles.
Do not run an Auto Match and Merge job on a base object that is used to define relationships between records in inter-table or intra-table match paths. Doing so will change the relationship data, resulting in the loss of the associations between records.