2

I know that every conflict-serialisable schedule is view-serialisable but the converse is not true. I read in a webpage that when a schedule is view-serialisable but not conflict-serialisable then there exist some blind writes. So what is a blind write?

  • 2
    Perhaps you should cite your source. Or provide excerpts. – Basil Bourque Sep 20 '15 at 4:26
7

If there is no read that happens prior to the first write then it is said to be a blind write.

Example. Consider the following schedule:

enter image description here

  • W3(X) is a blind write, as there is no read before write [R3(X) before W3(X)]

  • W2(X) is not a blind write, as a read happens before write [R2(X) before W2(X)]

-1

A blind write is a write operation e.g. W(X) by a transaction Ti after which the attribute X is not read by a transaction but some other transaction Tj performs another write operation on attribute X. Thus, the write operation by Ti becomes blind write.

  • So, Ti's write operation is blind write? I think Tj's – Saravanan Dec 21 '15 at 12:13
  • do transactions such as T3 that only contain a blind write ever abort? – Noah Watkins Mar 31 '17 at 20:10
-1

If a transaction without reading a data item directly performs a write operations ,then it is Blind or Dirty Write.

   T-1          T-2
   R(A)
   W(A)
               R(A)
               W(A)
   R(B)
   W(B)--------|
               |
               |     
              W(B)  (In this it has directly performed W(B) without reading 
                     B i.e R(B) )
  • 2
    It's not clear how this answer is different from sharhp's answer. – RDFozz Nov 15 '17 at 17:44

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