Virtual generated columns are not required to allow an index to be used in this case without incurring the cost of materializing `to_tsvector('english', message

Virtual generated columns are not required to allow an index to be used in this case without incurring the cost of materializing `to_tsvector('english', message)`. Postgres supports indexing expressions and the query planner is smart enough to identify candidate on exact matches. I'm not sure why the author doesn't use them but it's clearly pointed out in the documentation (https://www.postgresql.org/docs/current/textsearch-tables.html#TEXTSEARCH-TABLES-INDEX https://www.postgresql.org/docs/current/textsearch-tables.ht...). In other words, I believe they didn't need a `message_tsvector` column and creating an index of the form CREATE INDEX idx_gin_logs_message_tsvector ON benchmark_logs USING GIN (to_tsvector('english', message)) WITH (fastupdate = off); would have allowed queries of the form WHERE to_tsvector('english', message) @@ to_tsquery('english', 'research') to use the `idx_gin_logs_message_tsvector` index without materializing `to_tsvector('english', message)` on disk outside of the index. Here's a fiddle supporting it https://dbfiddle.uk/aSFjXJWz https://dbfiddle.uk/aSFjXJWz