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172 points frectonz | 2 comments | | HN request time: 0.422s | source

pglite-fusion is a PostgreSQL extension that allows you to embed SQLite databases into your PostgreSQL tables by enabling the creation of columns with the `SQLITE` type. This means every row in the table can have an embedded SQLite database.

In addition to the PostgreSQL `SQLITE` type, pglite-fusion provides the `query_sqlite`` function for querying SQLite databases and the `execute_sqlite` function for updating them. Additional functions are listed in the project’s README.

The pglite-fusion extension is written in Rust using the pgrx framework [1].

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Implementation Details

The PostgreSQL `SQLITE` type is stored as a CBOR-encoded `Vec<u8>`. When a query is made, this `Vec<u8>` is written to a random file in the `/tmp` directory. SQLite then loads the file, performs the query, and returns the result as a table containing a single row with an array of JSON-encoded values.

The `execute_sqlite` function follows a similar process. However, instead of returning query results, it returns the contents of the SQLite file (stored in `/tmp`) as a new `SQLITE` instance.

[1] https://github.com/pgcentralfoundation/pgrx

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robertclaus ◴[] No.42183246[source]
What are the use cases for this? I can't imagine designing a database schemas to use this in a typical product. Is it intended for hybrid applications to back up local user data directly with their account info?
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bravura ◴[] No.42183347[source]
The top line of the README says: "Embed an SQLite database in your PostgreSQL table. AKA multitenancy has been solved."

But I'm still having trouble trying to grok the intricacies of it. In a sense, I guess it has well isolated individual SQLite DBs and you'd have to go out of your way to join over them. With that said, does PostgreSQL manage and pool all the writes correctly? So you don't need to worry about SQLite concurrency issues?

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1. rswail ◴[] No.42183581[source]
You could join over them, but not really in the way you're thinking.

Each of the columns that are databases would be updated when the functions execute.

You could do weird crap like INSERT/DELETE as part of a postgres level SELECT.

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2. Tostino ◴[] No.42186004[source]
You can do that with any function already. This isn't new because of nested databases.