Hello everyone,
I am working on time stamping and so far I have found it to be quite challenging and I am wondering if someone can help me.
I have been working with this tutorial:
Consider the unserializable schedule below. Apply time stamping.
Code:
T1 T2
read A
read B
A=A+2
store A
read B
B=B*2
store B
B=B+1
store B
read A
A=A*5
store A
This is what I have come up with:
A A B B T1 T2 status
rd up rd up
t1 read A ok
t2 read B ok
t1 A=A+2 ok
t1 t1 store A ok
t1 read B ok why would I not rollback here?
t2 B=B*2 ok
t2 t2 store B no
rollback...........
t1 B=B+1 ok
t1 t1 store B ok
t2 read A ok
t2 A=A*5 ok
t2 t2 store A ok
I have a few other questions on procedures but I wanted to kinda get a feel on how I did with this tutorial first to see how much I understood it.
thanks,
dBforums
>
concurrency control with time stamping
03-18-07, 00:57
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