GATE CSE 2020
Q51.
Consider a relational database containing the following schemas. The primary key of each table is indicated by underlining the constituent fields. SELECT s.sno, s.sname FROM Suppliers s, Catalogue c WHERE s.sno=c.sno AND cost > (SELECT AVG (cost) FROM Catalogue WHERE pno = 'P4' GROUP BY pno) ;The number of rows returned by the above SQL query isQ52.
Consider a schedule of transactions T1 and T2: Here, RX stands for "Read(X)" and WX stands for "Write(X)". Which one of the following schedules is conflict equivalent to the above schedule?Q53.
Consider a TCP connection between a client and a server with the following specifications; the round trip time is 6 ms, the size of the receiver advertised window is 50 KB, slow-start threshold at the client is 32 KB, and the maximum segment size is 2 KB. The connection is established at time t=0. Assume that there are no timeouts and errors during transmission. Then the size of the congestion window (in KB) at time t+60 ms after all acknowledgements are processed is _______Q54.
Which of the following languages are undecidable? Note that \left \langle M \right \rangle indicates encoding of the Turing machine M. L_1=\{\left \langle M \right \rangle|L(M)=\varnothing \} L_2={\left \langle M,w,q \right \rangle|M on input w reaches state q in exactly 100 steps} L_3=\{\left \langle M \right \rangle|L(M) \;is \; not \; recursive\} L_4=\{\left \langle M \right \rangle|L(M) \;contains \; at \; least\; 21 \; members\}