jmeter jdbc variable names query

Question

Again more apologies from myself for being a Jmeter newbie - I'm a little stuck with the JDBC requests - I've trawled through the posts on this site for the last 3 hours - but I can't quite find anything relevant (unless I'm missing something).

My environment: Jmeter v2.11, JDK 7, Oracle 12

It's very simple - I have a JDBC Sampler that I need to setup to use the value that is provided by a JDBC PreProcessor.

Essentially I have a JDBCPreProcessor setup to identify the next (new) record's unique reference (call it applicationID)

JDBC PreProcessor Details

Select Statement --> select max(applicationID)+1 from table;

I have a JDBC Sampler setup that I need to use the 'max(applicationID)+1' value (determined by the JDBC preprocessor)

JDBC Sampler Details

Select Statement --> select status from table where applicationID = 'max(applicationID)+1'

I am unsure how to do this. I have looked at the instructions and a lot of other Jmeter JDBC request posts, but I'm afraid I can't find the relevant info I need.

I did try including adding a 'Variable Name' of 'maxrecordidvar' in the JDBC PreProcessor and set the JDBC Sampler query --> select status from table where applicationID = maxrecordidvar

HOWEVER - this (obviously) didn't work - I get an Oracle error 'ORA-00904: "MAXRECORDIDVAR": invalid identifier'

Again, many apologies if this is a stupid question and many thanks for all/any help anyone can provide!

I should highlight that I haven't just submitted this query without looking for answers. I think the RegEx expression extractor or perhaps the User Defined Variables might allow me to do what I need, but I'm still not sure of how to do what I need with these functions - cheers — sqeeky

Richard Friedman Richard Friedman · Accepted Answer · 2015-02-16T16:27:11

I have simulated a concept of this using MYSQL, but the test plan is similar.

JDBC pre processor to get an Integer
Use that integer in a following JDBC request

First, the JDBC PreProcessor and JDBC Request do not just simply emit to a single variable, but rather expose a few variables based on your name. For example

Query : select CAST(RAND() * 242 AS UNSIGNED);
Variable Name : foo

Which means later on I have access to

${foo_#} - the number of rows (which should be 1)
${foo_1} - the value in first column row 1

This query only has one column and row, otherwise ${foo_2} would be first column row 2. More docs at JDBC Request

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Second, to use with in my JDBC Request I had to use a Prepared Select Statement. Passing in ${foo_1} as the Parameter Value and INTEGER as the Parameter Type (I am using mysql).

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I posted a simulated load test and JMX File.

jmeter jdbc variable names query

2 Answers