@Override
	public synchronized void startTransaction() {
		redoList.clear();
		inTransaction = true;

		tmpChangedDataTypeIds = new HashSet<Long>();
		tmpChangedCategoryIds = new HashSet<Long>();
		tmpChangedSourceArchiveIds = new HashSet<Long>();
		tmpAddedDataTypeIds = new HashSet<Long>();
		tmpAddedCategoryIds = new HashSet<Long>();
		tmpAddedSourceArchiveIds = new HashSet<Long>();
	}
Construct a new DataTypeArchiveChangeSet.
@param addrMap the address map.
@param numUndos the number of undo change sets to track.
Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/program/database/DataTypeArchiveDBChangeSet.java