The following multiversion concurrency control has been proposed.
Reads are satisfied using the (committed) version of the database that existed when
the transaction made its first read request. Writes are controlled by long-duration
write locks on tables.
Does the control always produce serializable schedules? If not, give a nonserializable
schedule it might produce.
The control can produce schedules with both write skew and lost updates. Assume x
and y are in different tables.
Write Skew:
r1(x) r1(y) r2(x) r2(y) w1(x) w2(y)
Lost Update:
r1(x) r2(x) w1(x) commit1 w2(x)
You might also like to view...
The ________ paste option will cause pasted text to match the formatting in your document
A) Keep Text Only B) Merge Formatting C) Unformatted Text D) Keep Source Formatting
The statement if (document.getElementById) returns ____ when a browser is compatible with the W3C's version of DHTML.
A. false B. true C. yes D. an error message
In order to invoke the Copy( ) method of the File class, instantiate an object of the File class and send as an argument a filename.
Answer the following statement true (T) or false (F)
The pane on which graphical components appear is called the ____ pane.
A. window B. graphics C. component D. content