DVD Store Frequently Asked Questions


1. Can you please elaborate a little on the parameters to the utility. (I am specifically interested in S/M/L db size and think time)

S/M/L refer to the size of the database (10 MB/ 1 GB/ 100 GB). Things like
maximum number of products and customers are tied to the size. Think time is
the time between requests, while the simulated user is reading the previous
response and "thinking". You can set it to a value you think is
realistic (10 seconds?, 2 seconds?) and use this to estimate the number of
total supported users. Or you can set it to 0 and have the program drive the
backend as hard as possible for a measurement of total throughput (orders per
minute). Or you can adjust it if you are trying to drive an arbitrary number
of orders per minute.

2. Is the number of threads is equivalent to number of users ?

Number of threads is the number of connections to back end (web server or
database). If you set think time to a realistic value (as discussed in
question 1) then threads will be equal to users.

3. What is the difference between starting the prog with 10 threads from
a single machine compared to 5 threads from two different machine.

Unless you are hitting a resource bottleneck (either the client CPU or
networking) you shouldn't see much difference.

4. How do I interpret the data obtained from the ds2webdriver utility. (I
mean For example : et= 100.0 n_overall=280 opm=168 rt_tot_lastn_max=298
rt_tot_avg=115 rollbacks: n=121 %= 43.2)

See ./ds2/drivers/ds2_driver.txt

5. Is it fair to compare the DS2 database size (10 MB /1 GB/100 GB) with
no of warehouses in TPCC ?

No

6. I get the following error while loading the DVD Store on SQL Server:
Msg 4866, Level 16, State 1, Line 1 The bulk load failed. The column is too long in the data file for row 1, column 20. Verify that the field terminator and row terminator are specified correctly.

This is a result of the input load files being Linux/Unix based, while SQL Server is expecting DOS based text files. The difference between the two is that Unix text files just have a line feed, but DOS text files will have a carriage return at the end of each line. As a result the SQL load function never find the carriage return and thinks that the data is too big. If a version of Winzip is used to extract the ds2.tar file, then the text load files are automatically converted. There are also many Unix2DOS utilities available on the web that can be used to do the conversion as well.


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todd_muirhead
todd_muirhead
Latest page update: made by todd_muirhead , Jul 16 2008, 11:00 PM EDT (about this update About This Update todd_muirhead Edited by todd_muirhead

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