Question: ```js
I have 2 thread groups 
Thread group1: 
    csv data set configure
 {
  loop through the csv file(CSVFile.csv) that contain fileNames of json data to post
  eg: CSVFile.csv
    file1.json
    file2.json
    .....so on
 }
 http request (That posts the data to rest api) (lets call it POST request)
 {
  extracts data from each json file and put it in http body and post to rest api
  eg:
   extract data from file1.json and post
 }
  jsr223 post processor
  {
   extracting data from above http responce and saving it to a file
  }

Thread group2:
 csv data configure
 {
  reads data from csv file
 }
 http request (Perform GET operation on rest api) (lets call it GET request)
 {
  eg:
  GET ip:port/searchParameter=value
 }

```

Now the problem is how to trigger thread group2 every time a iteration of http request of thread group1 is complete and go for iteration 2 without waiting for thread group2 to complete.

```
eg:
POST request -> file1.json  completion should trigger GET request
As the GET request continues to execute
POST request -> file2.json should be excuted concurrently 

CAN I DO THIS?

```

Answer: 
I would recommend removing interim step of saving the response data into a file and read it in 2nd Thread Group, you could achieve the same within the bounds of a single Thread Group using [JSON Extractor](http://jmeter.apache.org/usermanual/component_reference.html#JSON_Extractor) and [JMeter Variables](https://jmeter.apache.org/usermanual/functions.html) - this approach will be much faster as in-memory operations are very quick comparing to disk IO operations and you will not have to worry about thread groups synchronisation. 

---

However if you would like to keep things as they are you can consider using [Inter-Thread Communication](https://jmeter-plugins.org/wiki/InterThreadCommunication/) plugin which can be used for [synchronisation](https://jmeter-plugins.org/img/examples/SynchronizationPluginsExample.jmx) of different Thread Groups basing on simple [FIFO](https://en.wikipedia.org/wiki/FIFO_(computing_and_electronics)) queue so 2nd Thread Group will start when it gets the signal from the first Thread Group. 

Check out [How to Use the Inter-Thread Communication Plugin in JMeter](https://www.blazemeter.com/blog/how-to-use-the-inter-thread-communication-plugin-in-jmeter) article for more information if needed. 

You can install Inter-Thread Communication Plugin using [JMeter Plugins Manager](https://jmeter-plugins.org/wiki/PluginsManager/) 

[![enter image description here](https://i.stack.imgur.com/UIOw8.png)](https://i.stack.imgur.com/UIOw8.png)
You can using if controller to handle. You check if thread 1 success, you put status success. If fail you put status fail

Thread 2 check status from Thread 1. If success then run http request