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 Transaction Processing Performance Council’s Version C On-Line Transaction Processing (TPC-C OLTP) 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 of transaction is shown.

(a) Determine the mean and standard deviation of the number of selects operations for a transaction from the distribution of types shown in the 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.

Solution:

Step 1 of 3:

Here the data regarding the frequency of each type of transactions is given.

Transaction |
Frequency |
Selects |
Updates |
Inserts |
Delets |
Nonunique selects |
Joins |

New order |
43 |
23 |
11 |
12 |
0 |
0 |
0 |

Payment |
44 |
4.2 |
3 |
1 |
0 |
0.6 |
0 |

Old 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 |

Using this we need to find the required values.