bigquery-etl/GRAVEYARD.md

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bigquery-etl Code Graveyard

This document records interesting code that we've deleted for the sake of discoverability for the future.

2020-04 Fenix baseline_daily and clients_last_seen

We are now using dynamically generated queries for generic Glean ETL on top of baseline pings, so we have deprecated previous versions of daily and last_seen tables.

Smoot Usage v1

The smoot_usage_*_v1* tables used a python file to generate the desktop, nondesktop, and FxA variants, but have been replaced by v2 tables that make some different design decisions. One of the main drawbacks of v1 was that we had to completely recreate the final smoot_usage_all_mtr table for all history every day, which had started to take on order 1 hour to run. The v2 tables instead define a day_0 view and a day_13 view and relies on the Growth and Usage Dashboard (GUD) to query them separately and join the results together at query time.

Shredder support for per-cluster deletes

For telemetry_stable.main_v4 shredder used SELECT statements over single clusters, then combined the result to remove rows from the table. This was an attempt to improve performance so that reserved slots would be cheaper than on-demand pricing, but it turned out to be slower than using DELETE statements for whole partitions.