0 0 votes Is it recoverable and why? Databases databases transaction-and-concurrency + – Shamim Ahmed 1.2k views answer comment Share Follow Print See all 8 Comments 8 8 Comments reply adarsh_1997 commented Nov 13, 2018 reply Follow flag there is dirty read(t3 reading the value written by t1)but since t1 has committed first before t2 . so thatsy it is recoverable 0 0 replyShare Shamim Ahmed commented Nov 13, 2018 reply Follow flag There is a lost update problem too. My Doubt is T2 is writing x which is used by write in T1 and T2 isn't committed. wont that be an issue ? 0 0 replyShare kumar.dilip commented Nov 14, 2018 reply Follow flag There is Write - read Conflict from t1 -> t2 So, For recoverable T1 should commit or abort first then t2. Above example is according to that. That's Why It is recoverable. 0 0 replyShare Gurdeep Saini commented Nov 23, 2018 reply Follow flag recoverable 0 0 replyShare Shubham Aggarwal commented Nov 28, 2018 reply Follow flag recovarable becoz no dirty read here 0 0 replyShare Harshitkmr commented Dec 21, 2019 reply Follow flag does the dirty read not count from t2 to t3 0 0 replyShare adarsh_1997 commented Dec 21, 2019 reply Follow flag @Harshitkmr no it doesnt count because T1 has written after T2.T3 is reading the value written by T1 not T2 0 0 replyShare Harshitkmr commented Dec 21, 2019 reply Follow flag ok leaving this aside while constructing precedence graph for cs schedules we would still take t2 to t3 conflict right? 0 0 replyShare Please log in or register to add a comment.
1 1 vote It is recoverable because T3 need a data item X that was previously written by T1 condition is that the commit operation of T1 should appear before the commit operation of T3 .that is true so recoverable. sandeep singh gaur answered Nov 14, 2018 sandeep singh gaur comment Share Follow 0 reply Please log in or register to add a comment.
