[I_am_tiberius]

That sounds awesome. Are you saying you still use your normal OLTP table for writing data and the columnstore table is always in sync with that OLTP table (that's fantastic)? I ready it works with duckdb - how does it work? I guess there's no chance this is going to be available on Azure Flexible Server anytime soon.

[moonikakiss]

exactly. we take the CDC output / logical decoding from your OLTP tables and write into a columnar format with <s freshness.

We had to design this columnstore to be 'operational' so it can keep up with changing oltp tables (updates/deletes).

You'll be able to deploy Mooncake as a read-replica regardless of where your Postgres is. Keep the write path unchanged, and query columnar tables from us.

--- v0.2 will be released in preview in ~a couple weeks. stay tuned!

[I_am_tiberius]

Ah, I see. So there's a replication process similar to ClickHouse's MaterializedPostgres. Ideally, there would be functionality allowing a columnstore query to wait until all writes to the OLTP tables — up to the query's execution time — are available. This would make the system truly Postgres-native and address issues that no other system currently solves.

[moonikakiss]

yep exactly. we can wait for replay LSN. So you're only reading once all writes to OLTP are complete.

[I_am_tiberius]

A follow up question: You can't join columnar tables with OLTP tables, right?

[moonikakiss]

yes you can. Even if the columnar tables are in the read replica. you'll be able to do joins with your OLTP tables

[I_am_tiberius]

That's great, thanks.