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I need to perform a load test against a pgbouncer. All the clients perform an SSH Tunnel before enstablishing a database connection to the database (through the pgbouncer). It's something like this:

sshpass -p 'MY_PSW' ssh -o StrictHostKeyChecking=no -N -L LOCAL_PORT:127.0.0.1:63666 PGBOUNCER_USER@PGBOUNCER_ADDRESS -p PORT >/dev/null 2>&1 &

My Jmeter project has three thread Groups at the moment:

  1. SetUp Thread Group: In which I make a connection to a different database to select a random username and schema

  2. Query Thread Group: In which I perform the JDBC connection using the previous user (which became a property using props.put("schema", vars.get("schema_1")); into the BeanShell Assertion) and the queries

  3. TearDown Thread Group: In which I close the ssh Tunnel.

Now every first time I run the test from the GUI, the data select (JDBC request) into the Query Thread Group gives me an error:

Cannot create PoolableConnectionFactory (FATAL: "trust" authentication failed)

After that, if I run the test again, everything works. I checked the content of the variables and properties with a Debug sampler and everything is correct.

The main problem starts when I run the test without the GUI. It always fails because of that error.

I actually don't like the fact that I have to enstablish the SSH tunnel running the command with an OS Process Sampler, but I can't find any better solution. The SSH tunnel is a part of the test, I don't need that for the master/slave configuration of JMeter.

I would appreciate a lot for a solution or a suggestion to make this work. Thanks.

Federico Loro
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2 Answers2

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If you're using the command in the OS Process Sampler it's being run in the background therefore my expectation is that the OS Process Sampler returns the SampleResult immediately and the tunnel is not up yet.

Then when the "Query Thread Group" starts as per JMeter Test Elements execution order JDBC Connection Configuration tries to establish the connection using local port which is not fully established. The fact that the issue is reproducible in non-GUI mode might be the confirmation for my guess as JMeter works much faster in non-GUI as it doesn't need to waste time and resources for GUI refreshing and propagating sample results to listeners.

My expectation is that if you add i.e. Flow Control Action sampler to the setUp Thread Group and configure it to "sleep" for a couple of seconds it should resolve your issue. If it doesn't - try increasing JMeter logging verbosity for the JDBC Test Elements by adding the next line to log4j2.xml file

<Logger name="org.apache.jmeter.protocol.jdbc" level="debug" />

and compare the entries for "successful" and "failed" executions in the jmeter.log file.

Dmitri T
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  • First and foremost thank you for the help. The first method (adding a Flow Control Action) didn't work. But adding the debug helped me finding the problem. The first time I run the test the property I put the value in into the setUp Thread Group doesn't actually contains a value. In fact, this is the error message: 2021-12-14 10:23:46,338 DEBUG o.a.j.p.j.c.DataSourceElement: Driver: org.postgresql.Driver DbUrl: jdbc:postgresql://127.0.0.1:50539/JB7 User: sshUser At the end there's the name of the property and not the value. But I don't understand how I could solve this. – Federico Loro Dec 14 '21 at 10:30
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Ok, I managed to find the solution. Thank to Dmitri T Answer, I could track the problem, which was about the property not being properly set.

I was using the BeanShell Assertion to set the property after the result of the JDBC request in the setUp Thread Group. Apparently, the BeanShell Assertion is executed at the end of the entire run, so the property where being set at the end. During the first execution, the property is empty.

I used the Beanshell Sampler instead and now it works.

Federico Loro
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