Show HN: Lightweight data analytics using SQLite, Bash and DuckDB

Over the last 12 months, in parallel to using Google BigQuery, I have built my own processing pipeline using SQLite and DuckDB.

What amazes me is that it works surprisingly well and costs much less than using BigQuery.

Roughly speaking, here's what I do: A SQLite database receives IoT sensor data via a very simple PHP function. I currently use the FlightPHP framework for this. The data is written to a table within the SQLite database (WAL mode activated) and states are updated by the machines using triggers.

Example of a trigger

CREATE TRIGGER message_added AFTER INSERT ON messages BEGIN INSERT OR REPLACE INTO states VALUES ( new.id, new.status, new.time_stamp, new.current_present, new.voltage_present)

This allows me to query the current status of a machine in real time. To do this, I again use a simple PHP function that provides the data via SSE. In the frontend, a simple Javascript method (plain vanilla JS) retrieves the JSON data and updates the HTML in real time.

    const source_realtime = new EventSource("https://myapi/sse_realtime_json");
    source_realtime.onmessage = function(event) {
        var json = JSON.parse(event.data); };

For a historical analysis - for example over 24 months - I create a CSV export from the SQLite database and convert the CSV files into Parquet format.

I use a simple BASH script that I execute regularly via CronJob.

Here is an excerpt

# Loop through the arrays and export each table to a CSV, then convert it to a Parquet file and load into the DuckDB database for (( i=0; i<${arrayLength}; i++ )); do db=${databases[$i]} table=${tables[$i]}

  echo "Processing $db - $table"
  
  # Export the SQLite table to a CSV file
  sqlite3 -header -csv $db "SELECT * FROM $table;" > parquet/$table.csv
  
  # Convert the CSV file to a Parquet file using DuckDB
  $duckdb_executable $duckdb_database <<EOF

 -- Set configurations
 SET memory_limit='2GB';
 SET threads TO 2;
 SET enable_progress_bar=true;

 COPY (SELECT * FROM read_csv_auto('parquet/$table.csv', header=True)) TO 'parquet/$table.parquet' (FORMAT 'PARQUET', CODEC 'ZSTD');
 CREATE TABLE $table AS SELECT * FROM read_parquet('parquet/$table.parquet');

EOF

Now finally my question: Am I overlooking something? This little system works well for currently 15 million events per month. No outtages, nothing like that. I read so much about fancy data pipelines, reactive frontend dashboards, lambda functions ...

Somehow my system feels "too simple". So I'm sharing it with you in the hope of getting feedback.