Virtual Table Server and How to use it with LoadRunner

1. How to use VTS with LR
Kranthi Paidi
1

2. What is VTS
2
 VTS – Virtual Table Server
 A windows service which maintains an in memory database that can be accessed
by a number of load generators on a network
 VTS helps different data dependent scripts “talk-to” each other during a load test
 Unlike the parameter files which involves file operation in order to be changed
once the test starts and thus bringing in concurrency issues, VTS holds and shares
the values that “producer” scripts generate so that “consumer” scripts can act
upon the data.
 For example, if a script called Add_Issue generates an Issue ID which is assigned to
a particular user, using VTS, this Issue ID can be “inserted” into a “table” during run
time and “retrieved” by Close_Issue script by that particular user.
 Thus, VTS can be treated (and is a kind of) database.
 The only difference here is that you cannot “query” this database. For example,
you cannot write a query like “select * from table_1 where user_ID=“kpaidi””
 HP LoadRunner does not “officially” provide any support to VTS. This is a third
party “add-in” that you have to use by yourself.

3. What is VTS
3
 Even though HP does not support this tool, thousands of users have used this and
are still using it without any problems.
 The last available version is VTS 2. This is no longer being developed, but, VTS2 is
completely stable and has no issues reported over a significant time.
 Attached in this slide is VTS.rar which has all setup files required.
VTS

4. Installing VTS
4
 Minimum system requirements:
 A 1-CPU 300Mhz+ Windows NT/2000
 The total amount of data that VTS supports is limited by the Operating System’s
maximum limit on process memory (2Gig to 3 Gig)
 VTS is tested for 1 million entries per row. It supports only 32,767 rows
 VTS should be installed on your controller(s) and all load generators that you intend
to make use of in your load test.
 For each machine, do the following:
 Extract the zip file and click vtsinstall.exe
 VTS automatically selects “C:Program FilesHPLoadRunner as installation directory
 Select install
 Open cmd prompt with elevated privileges
 Cd to “C:Program FilesHPLoadRunnerbin”
 Type regsvr32.exe vtsctls.ocx
 Type regsvr32.exe msflxgrd.exe

5. Setting up the Server
5
 If your tests involve large data creation and consumption, please plan to have a
separate machine as VTS server other than controller and load generator. Working
on large sets of data will have its impact on the memory and network bandwidth
thus affecting the load generators and controller. You do not want to introduce
bottlenecks in the test design itself.
 If your tests have minimal amount of data being operated up on (not more than a
few MB), choose a less utilized load generator.
 Whatever the machine you choose, determine the physical IP of the machine using
“ipconfig /all” command from cmd prompt.
 Once you determined the IP, check what ports are available on the machine. Use
the command “netstat –an”. Choose a port that is available (I am choosing 8888
here)
 Once you do the above, open a notepad and type the following
 ECHO ON
 CD “C:Program FilesHPLoadRunnerbin”
 START vtconsole –port 8888 –launch

6. Setting up the Server
6
 Save the notepad as “START_VTS.bat” on a location you prefer (I prefer Desktop)
 Click the batch file. You should see a window like this –

7. Setting up the Server
7
 Your VTS server is UP and READY now. You can use this as a database to store and
retrieve values during a scenario run.
 In the next few slides, we will see how to connect to a VTS from a VUGen script,
how to write data, how to retrieve data and error handling.

8. Connecting to VTS from VUGen
8
 Include the following at the top of vuser_init, action, vuser_end sections
 #include “as_web.h”
 #include “vts2.h”
 Your init, action and end sections will look like this –
 In the vuser init section, write the following code to connect to VTS

9. Connecting to VTS from VUGen
9
 In the vuser_end section, write the following code. This disconnects the
vuser from vtc.
 If your VTS is up and running (remember the START_VTS.bat?), running
the above VuGen code should not write any messages to the output
screen. It should look like below:

10. Connecting to VTS from VUGen – Error Codes
10
 If you have any problems with VTS, the following error codes are returned:
 #define VTCERR_INVALID_CONNECTION_INFO -10000 > verify the server name attribute.
 #define VTCERR_FAILED_TO_RESOLVE_ADDR -10001
 #define VTCERR_FAILED_TO_CREATE_SOCKET -10002
 #define VTCERR_FAILED_TO_CONNECT -10003 > the vtconsole is not running.
 #define VTCERR_INCOMPLETE_REQUEST -10100
 #define VTCERR_FAILED_TO_RECV_RESPONSE -10101
 #define VTCERR_INCOMPLETE_RESPONSE -10102
 #define VTCERR_RESPONSE_ARGS_UNMATCH -10103
 #define VTCERR_OPERATION_ERROR_BASE -11000

11. Writing data into the server - example
11

12. Data Manipulation in VTS
12
 Insert Data Element:
 Inserts operation data into the column specified by column name
 Insert Unique Data:
 Inserts operation data only if the data is unique
 Update Data Element:
 Updates the value of data element in the column name at selected location
 Increment Data Element:
 Increments the numerical data element in the column name at selected location by the number
specified
 Query data element:
 Obtains the value of the data element in the column name at location specified
 Clear Data Value:
 Clears the data in the column name at location specified
 Clear Entire Column:
 Clears the entire column

13. Client side API – LR functions
13
 VTS supports two types of functions. Raw VTS functions and LR version of the same
functions. The definitions for both the type of functions are available in vts2.
 We will discuss and see only LR version of the fuctions
 Connect/Disconnect:
 PVCI lrvtc_connect(char *servername, int portnum, int options);
 Options: 0 for None, VTOPT_KEEP_ALIVE for keep connection alive
 PVCI is a typedef int variable
 lrvtc_disconnect();
 Query a Column: retrieves data from a Column specified by name and index
 lrvtc_query_column(char *ColumnName, int RowIndex);
 Query a Row: retrieves data from all columns in a row specified by row index
 lrvtc_query_row(int RowIndex);

14. Client side API – LR functions
14
 Send data to a column: sends data to the next row of the column specified
 lrvtc_send_message(char *columnName, char *columnValue);
 Send unique data to a column : sends a data to the next row of column only if it is
unique in that column
 lrvtc_send_if_unique(char *columnName, char *columnValue);
 Returns 1 for pass and 0 for fail

15. Client side API – LR functions
15
 Send entire row: Sends data into a row with specified column names
 lrvtc_send_row1(char *columnNames, char *messages, char *delimiter, unsigned char
sendflag);
 Status code returned PVCI 1=pass, 0=fail
 Update data: Updates data at specified column and index
 lrvtc_update_message(char *columnName, int Index, char *message);

16. Client side API – LR functions
16
 Update entire row: Updates row data at specified column index
 lrvtc_update_row1(char *columnNames, int index, char *messages, char *delimiter);
 Clear Message: Clears the data at specified column and Index
 lrvtc_clear_message(char *columnName, int index);

17. Client side API – LR functions
17
 Clear Column: Clears all data in the given Column
 lrvtc_clear_column(char *columnName);
 Clear row: Clears all data in a row of specified index
 lrvtc_clear_row(int index);

18. Client side API – LR functions
18
 Retrieve message: retrieves and clears the first data element from a column
 lrvtc_retrieve_message(char *columnName);

19. Client side API – LR functions
19
 Retrieve multiple messages: retrieves and clears the first data element from a row
as specified by column names
 lrvtc_retrieve_messages1(char *columnNames, char *delimiter);

20. Thank You
20