Each group of operations can have at most :limit:`1000 operations <Write Command Operation Limit Size>`. If a group exceeds this :limit:`limit <Write Command Operation Limit Size>`, MongoDB will divide the group into smaller groups of 1000 or less. For example, if the bulk operations list consists of 2000 insert operations, MongoDB creates 2 groups, each with 1000 operations.
The sizes and grouping mechanics are internal performance details and are subject to change in future versions.
To see how the operations are grouped for a bulk operation execution, call :method:`Bulk.getOperations()` after the execution.