Q$3.$ Transaction & Concurrency Control

$3\mathrm{.}1.$

Consider the transactions T$1,$ T$2,$ and T$3$ and the schedules S$1$ and S$2$ given below.

T$1$: r$1($X$)$;r$1($Z$)$;w$1($X$)$;w$1($Z$)$

T$2$: r$2($Y$)$;r$2($Z$)$;w$2($Z$)$

T$3$: r$3($Y$)$;r$3($X$)$;w$3($Y$)$

S$1$: r$1($X$)$;r$3($Y$)$;r$3($X$)$;r$2($Y$)$;r$2($Z$)$;

w$3($Y$)$;w$2($Z$)$;r$1($Z$)$;w$1($X$)$;w$1($Z$)$

$S2$ : r$1($X$)$; r$3($Y$)$; r$2($Y$)$; r$3($X$)$; r$1($Z$)$;

r$2($Z$)$; w$3($Y$)$; w$1($X$)$; w$2($Z$)$; w$1($Z$)$

Analyze which one of the schedules is conflict$-$serializable?