An article in the Journal of Database Management [\"Experimental Study of a Self
ID: 3024195 • Letter: A
Question
An article in the Journal of Database Management ["Experimental Study of a Self-Tuning Algorithm for DBMS Buffer Pools" (2005, Vol. 16, pp. 1–20)] provided the workload used in the TPC-C OLTP (Transaction Processing Performance Council's Version C On-Line Transaction Processing) benchmark, which simulates a typical order entry application. The frequency of each type of transaction (in the second column) can be used as the percentage of each type of transaction. The average number of selects operations required for each type transaction is shown.
Transaction
Frequency
Selects
Updates
Inserts
Deletes
Non-Unique Selects
Joins
New order
41
23
11
12
0
0
0
Payment
46
4.2
3
1
0
0.6
0
Order status
4
11.4
0
0
0
0.6
0
Delivery
5
130
120
0
10
0
0
Stock level
4
0
0
0
0
0
1
a) Determine the mean and standard deviation of the number of selects operations for a transaction from the distribution of types shown in the above table.
b) Determine the mean and standard deviation of the total number of operations (selects, updates, ... , and joins) for a transaction from the distribution of types shown in the table below.
Transaction
Frequency
Selects
Updates
Inserts
Deletes
Non-Unique Selects
Joins
New order
41
23
11
12
0
0
0
Payment
46
4.2
3
1
0
0.6
0
Order status
4
11.4
0
0
0
0.6
0
Delivery
5
130
120
0
10
0
0
Stock level
4
0
0
0
0
0
1
Explanation / Answer
a)
Mean of number of selects operations = sum (selects*% of transcations ) =18.318
variance = 1075.203-(18.318)^2 =739.6537
Standard deviation =sqrt(variance) =sqrt(739.6357) = 27.2
b)
Mean number of total operations =sum(total operations*%of transactions) =36.428
variance =4288.9-(36.428)^2 = 2961.98
standard deviation =sqrt(variance) = 54.42
Transaction Frequency Selects Updates Inserts Deletes Non-Unique Selects Joins percentage of transcation selects*%of tansaction selects^2*%of tansaction New order 41 23 11 12 0 0 0 0.41 9.43 216.89 Payment 46 4.2 3 1 0 0.6 0 0.46 1.932 8.1144 Order status 4 11.4 0 0 0 0.6 0 0.04 0.456 5.1984 Delivery 5 130 120 0 10 0 0 0.05 6.5 845 Stock level 4 0 0 0 0 0 1 0.04 0 0 18.318 1075.203Related Questions
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