# Query Performance Gauge

This is a little script to measure the performance of queries against a Trino or MySQL instance. You can use it to run
several queries and measure how long it takes for results to come back to your local machine.

## How to use

1. First, you need to install the package in your Python installation or a virtual environment. If you have our Google 
Drive Shared Drive replicated locally, you can do it like this:

```commandline
pip install "git+file:///g:\shared drives\data drive\90 useful\trino_query_performance_gauge@master"```
```

2. After, you need to make a config file. See below details on how to compose one.

3. Once you have your config file ready, run the following command from the terminal.

```commandline
measure_query_performance --config my_config_file.json
```

## Composing a config file

You can take a look at the `example-config.json` in this repository.

A few notes:
- The valid engines are `"trino"` and `"mysql"`.
- You can place as many queries as you would like in the `queries_to_measure` list.
- I advice you to make the first query a silly, fast query such as `SELECT 1` to validate your connection and 
  quickly confirm that everything is set up properly.



## A few more details

- Queries are run sequentially, as in the second query will only start after the first query is finished.
- For this to work, your local machine must have access and permission to the connection you are targeting, so 
  remember to set up VPNs and other necessary configs properly.
- A peculiarity: when using MySQL through an SSH tunnel, the port number used by the remote MySQL should be
  free in your local machine. That means that if the MySQL database is listening on port 3306, your local machine
  should have port 3306 free before running this.
- Queries in JSON must be stored in a single line. A bit of a headache, I know. JSON limitations. You can use [this 
  webpage](https://sqlformatter.org/) to easily jump between prettified and one-line formats for any query.