Incremental data load is a way to add new data or updates to an existing dataset in small chunks, instead of one big batch. This method is often used in database management to ease the load on the system and to keep data consistent and intact. When it comes to Supabase, a full-stack Firebase alternative, you might want to use incremental data loads to keep your app's data always up-to-date. This reduces the stress on client-side databases and boosts your app's performance.

Before you start with incremental data loading, make sure your Supabase environment is set up correctly. Install the necessary packages, create a new project via the Supabase dashboard, and link it to your development environment.

Supabase uses a PostgreSQL database, so you'll need to set up a table schema that records the latest timestamp or record ID that has been loaded. This helps in setting load markers for incremental data updates.

Use the Supabase client library to load your initial data into your created table. Do this only once, as the subsequent data operations will be done incrementally.

const { data, error } = await supabase
  .from('your-table')
  .insert([
     { id: 1, name: 'John', updated_at: '2022-01-01T00:00:00Z' },
     { id: 2, name: 'Paul', updated_at: '2022-01-02T00:00:00Z' },
  ])

Initialize the last loaded record's timestamp or ID as a marker for incremental loads. Update this marker every time new data is loaded incrementally.

let last_loaded_record = '2022-01-02T00:00:00Z';

Set up a script for incremental data load using the Supabase client library. This script will pull in new records from the source, with records greater than the last loaded timestamp or ID. Also, make sure the script updates the marker as new records are loaded.

const { data, error } = await supabase
  .from('your-table')
  .insert([
     { id: 3, name: 'George', updated_at: '2022-01-03T00:00:00Z' },
  ])
  .gt('updated_at', last_loaded_record)

Ensure the last_loaded_record is updated with the latest updated_at timestamp.

After writing the script, test it several times to make sure it works and delivers data correctly. Once it's fully tested and tweaked as needed, schedule the script to run at your desired intervals.

Remember, incremental data load in Supabase is subject to the data storage and transfer limits of your Supabase plan. The capacity of your app's client-side databases can also affect the performance of incremental data loading. So, optimize your app and the script to handle these factors.