RECOVERABLE SCHEDULE

Question

Is this recoverable schedule? If yes then give reason.

Comments

Yes it's recoverable schedule .because  there is no dirty read

Answer 1

Transaction T3 reads  value of x written by transaction T1 after its commit. Therefore it is recoverable

Condition for recoverable schedule is that " if a transaction T1  performs a dirty read from other transaction T2 then transaction T1 should commit  after T2 "

Comments

here we will not consider t2 write. because t1 update write on x after t2 write.

if my logic is wrong please let me correct!

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Yes bro , because no one reads immediately after T2 writes and it is overwritten by t1

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I think no... Because as per Navathe 
" A schedule S is recoverable if no transaction T in S commits until all transactions T that have written some item X that T reads have
committed... " 

Here T2 has written on X & is still uncommitted & T3 has read X & is committed without waiting for T2 to commit... 
Then how it can be recoverable ? 

@Niraj Singh 2

​​​​​​ @learner_geek

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