Crowdly
Add to Chrome
INTRO. TO DATABASE MGMT. SYST.
Looking for INTRO. TO DATABASE MGMT. SYST. test answers and solutions? Browse our comprehensive collection of verified answers for INTRO. TO DATABASE MGMT. SYST. at moodlenew.iitd.ac.in.
Get instant access to accurate answers and detailed explanations for your course questions. Our community-driven platform helps students succeed!
Validation‐based concurrency control always requires buffering all writes until commit time.
Which of the following scheduling graphs indicates a cycle (and thus non‐serializable schedule)?
Consider two transactions T1 and T2 with timestamps TS(T1)=5 and TS(T2)=10 and the following schedule:
T1. | T2--------------+------------- write(A) | | read(A)
Under the basic timestamp ordering protocol, what happens?
Consider the following transaction schedule. Indicate if it is conflict-serializable or not:
| T1 | T2+---------+--------| read(A) | | | read(B)| read(B). | | | write(B)| write(A) | | write(B) | | | read(A)| | write(A)| commit | | | commit
Consider this schedule under basic 2PL where locks may be released as soon as the write is done (so uncommitted writes can be seen by others)
| T1 | T2+--------------+-------------| lock_X(A) | | write(A) | | unlock(A) | | | lock_S(A)| | read(A)| abort | | |
Under this protocol, does the schedule exhibit
Under basic two‐phase locking, once a transaction releases any lock, it cannot acquire any new locks.
Deadlock avoidance using wait‐die and wound‐wait schemes is typically integrated with which protocol?
In a timestamp‐ordering protocol, a read operation may ever cause the reading transaction to abort if the data item was last written by a younger transaction.
Consider the following schedule under basic 2PL
| T1 | T2+--------------+-------------| lock_S(A) | | | lock_S(B)| lock_X(B) | | | lock_X(A)
Under this 2PL protocol, does the schedule exhibit
Assuming that and are sets and and