add more features for transaction
add more features for transaction

cmu-db/cmdbac,cmu-db/cmdbac,cmu-db/db-webcrawler,cmu-db/db-webcrawler,cmu-db/db-webcrawler,cmu-db/cmdbac,cmu-db/cmdbac,cmu-db/cmdbac,cmu-db/db-webcrawler,cmu-db/db-webcrawler