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Comment by quectophoton | Hacker News Reader

> And then by magic the results of this query will just always exist and be up-to-date.

With PostgreSQL the materialized view won't be automatically updated though, you need to do `REFRESH MATERIALIZED VIEW` manually.

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Did I miss in the article where OP reveals the magic database that actually does this?

3rd party solutions like https://readyset.io/ and https://materialize.com/ exist specifically because databases don’t actually have what we all want materialized views to be.

These startups (and a handful of others) are what I meant!

What others do you know of?

Feldera

Feldera, RisingWave, DeltaStream, Epsio, Decodable, Confluent all seem to have some offerings in this space. Probably others too!

You can do targeted materialized view updates via triggers. It's definitely verbose but does give you a lot of control.

I'm currently parking PostgREST behind Fastly (varnish) for pretty much the same benefits plus edge CDNs for my read APIs. I really just use materialized views for report generation now.

In the analytics world, BigQuery MVs seem pretty cool. You can tune the freshness parameters, it will maintain user-specific row-level security, and even rewrite regular queries to use the pre-computed aggregates if possible.

But I don't think there is anything similar in the GCP transactional db options like Spanner or CloudSQL.

Just landed here to write this. Materialized Views are _very_ implementation specific and are definitely _not_ magic.

It's important to understand how your implementation works before committing to it.

Curious if anyone know any implementation where they would be automatically updated?

Now that would be awesome!

EDIT: come to think of it, it would require going through CDC stream, and figuring out if any of the tables affected are a dependency of given materialized view. Maybe with some ast parsing as well to handle tenants/partitions. Sounds like it can work?

MSSQL and Sybase SQLAnywhere has options for that, we use it a fair bit with both.

At least on SQLAnywhere it seems to be implemented using triggers, ie not unlike what one would do if rolling your own.

Postgesql knows when you try to drop its dependencies so shouldnt be to hard to watch traffic

Oracle will do - a couple of options, either a full rebuild or an incremental rebuild.

Also, latest Oracle version (23ai) has added "concurrent on-commit fast refresh" functionality, where concurrent transactions' changes are rolled up to the MV concurrently (previously these refreshes were serialized).

https://oracle-base.com/articles/23/materialized-view-concur...

From the article: "Concurrent refreshes will only happen if there are no overlaps in the materialized view rows updated by each session."

Do give us at Feldera a shot -- full IVM for arbitrary SQL + UDFs: https://github.com/feldera/feldera/

There is a PostgreSQL extension that adds support for incremental updates to materialised views: https://github.com/sraoss/pg_ivm

Postgres materialized views are pretty terrible / useless compared to other rdbms. I’ve never found a usecase for the very limited pg version.

having a dataset refresh on a timer and cache the result for future queries is pretty useful

I've only used Postgres' and (ages ago) MSSQL's materialized views. What is pg missing compared to the others?

I've found them VERY useful for a narrow range of use cases but, I probably don't realize what I'm missing.

In Postgres a materialized view is basically a table that remembers the query used to generate it. Useful if you want to trigger the refreshes without knowing the queries.

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