I'd like to see someone provide a description of why there are no conflicts between transactions A and transaction B on this slide. The transactions certainly access the same data.
jazzbass
Even though transactions A and B access the same data, there is no overlap between:
The read set of A and the write set of B.
The read set of B and the write set of A.
The write set of A and the write set of B.
In other words, A doesn't modify any data that B accesses, and B doesn't modify any data that A accesses. The transactions only share read values, therefore they are 'compatible'.
iZac
I second @jazzbass! No overlap of data being written parallel to the read.
Zarathustra
There is no conflict for the same reason that two people can gather apples from the same tree at the same time.
I'd like to see someone provide a description of why there are no conflicts between transactions A and transaction B on this slide. The transactions certainly access the same data.
Even though transactions A and B access the same data, there is no overlap between:
The read set of A and the write set of B.
The read set of B and the write set of A.
The write set of A and the write set of B.
In other words, A doesn't modify any data that B accesses, and B doesn't modify any data that A accesses. The transactions only share read values, therefore they are 'compatible'.
I second @jazzbass! No overlap of data being written parallel to the read.
There is no conflict for the same reason that two people can gather apples from the same tree at the same time.