revori
PipelineDB
revori | PipelineDB | |
---|---|---|
1 | 3 | |
10 | 2,603 | |
- | 0.0% | |
0.0 | 0.0 | |
over 9 years ago | about 2 years ago | |
Java | C | |
GNU General Public License v3.0 or later | Apache License 2.0 |
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revori
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Ask HN: Is there a way to subscribe to an SQL query for changes?
I've implemented a RDBMS that supports this [1]. It handles joins, views (which are automatically materialized and incrementally updated), etc. It's memory only, and it doesn't support exotic stuff like recursive CTEs, but it does exactly what you're asking for. We used it in production successfully for frequently-updated real time data at the company where I used to work.
Notably, it uses persistent search trees such that each revision shares structure with the previous one, which makes diffing two closely-related revisions extremely efficient (just skip over any shared structure). Subscribers just receive a stream of diffs, with backpressure handled automatically by skipping over intermediate revisions. See [2] for a more detailed summary.
It also exposes revisions as first-class objects, which allows you to tag and diff them. Specifically, you can run arbitrary queries on both revisions and diffs. See [3] for examples.
It's no longer maintained, unfortunately. Someday I may revive it, perhaps adding support for spilling data that won't fit in memory to log-structured merge trees. I'd also rewrite it in a language like Rust, which will help flatten some of the more pointer-heavy data structures and reduce tail latencies. If anyone is interested in seeing that happen or helping out, let me know.
I'm really surprised this still isn't supported in mainstream DBMSes. The MVCC model in PostgreSQL seems particularly well suited to it.
[1]: https://github.com/ReadyTalk/revori
PipelineDB
- PostgreSQL Is Enough
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The database inside out with event streams
I was experimenting with continuous sql queries in postgres for the same purpose. https://github.com/pipelinedb/pipelinedb
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Ask HN: Is there a way to subscribe to an SQL query for changes?
PipelineDB might be of interest. https://github.com/pipelinedb/pipelinedb
What are some alternatives?
rethinkdb_rebirth - The open-source database for the realtime web.
TinyDB - TinyDB is a lightweight document oriented database optimized for your happiness :)
cainophile
PyPika - PyPika is a python SQL query builder that exposes the full richness of the SQL language using a syntax that reflects the resulting query. PyPika excels at all sorts of SQL queries but is especially useful for data analysis.
pg-live-select - Live Updating PostgreSQL SELECT statements
pickleDB - pickleDB is an open source key-value store using Python's json module.
flow - 🌊 Continuously synchronize the systems where your data lives, to the systems where you _want_ it to live, with Estuary Flow. 🌊
ZODB - Python object-oriented database
timely-dataflow - A modular implementation of timely dataflow in Rust
MerkavaDB - A fast ordered NoSQL database.
noria - Fast web applications through dynamic, partially-stateful dataflow
SSShelf - An ORM for S3