steve-chavez
bcc8998e5e
This adds a new log line that shows each schema cache query time individually, only on `log-level=debug`. Like so: ``` $ PGRST_LOG_LEVEL=debug postgrest-with-pg-17 -f test/spec/fixtures/load.sql postgrest-run .... 10/Apr/2026:21:48:45 -0500: Schema cache queried in 192.2 milliseconds 10/Apr/2026:21:48:45 -0500: tables: 72.027 ms, keydeps: 20.118 ms, rels: 6.189 ms, funcs: 35.010 ms, comprels: 4.319 ms, dreps: 1.614 ms, mhandlers: 7.419 ms, tzones: 43.025 ms ``` This helps debug specific schema cache queries being slow like on https://github.com/PostgREST/postgrest/issues/4613#issuecomment-4210191065 and https://github.com/PostgREST/postgrest/issues/3046#issuecomment-3469059948. It also closes https://github.com/PostgREST/postgrest/issues/3215, which main motivation was to find out which query is slow. Implementation details --------------------- To time each query inside a transaction in pure SQL, we do: ```sql -- start timer select set_config('pgrst.tmp_x', clock_timestamp()::text, false); -- run the query select <query> -- end timer select set_config('pgrst.tmp_x', (clock_timestamp() - current_setting('pgrst.tmp_x', false)::timestamptz)::text, false); -- .... repeated for every query -- at the end we capture all the timings with select extract('milliseconds' from current_setting('pgrst.tmp_x', false)::interval), extract(..; ``` Considerations -------------- Only added this on `log-level=debug` because while the queries are fast and the data is valuable, it triples the amount of queries we run during schema cache refresh, which could be troublesome on slow networks. It's possible to reduce the amount of queries by starting and stopping timers in one statement, but this would still double the amount of queries and makes the code messy, doesn't seem worth it. Also it would pollute pg_stat_statements, it's only required to debug certain extreme cases anyway.
PostgREST serves a fully RESTful API from any existing PostgreSQL database. It provides a cleaner, more standards-compliant, faster API than you are likely to write from scratch.
Sponsors
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Big thanks to our sponsors! You can join them by supporting PostgREST on Patreon.
Usage
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See the docs for how to install PostgREST on your platform. You can also use Docker.
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Invoke for help:
postgrest --help
Documentation
Latest documentation is at postgrest.org. You can contribute to the docs in PostgREST/postgrest/docs.
Performance
TLDR; subsecond response times for up to 2000 requests/sec on Heroku free tier. If you're used to servers written in interpreted languages, prepare to be pleasantly surprised by PostgREST performance.
Three factors contribute to the speed. First the server is written in Haskell using the Warp HTTP server (aka a compiled language with lightweight threads). Next it delegates as much calculation as possible to the database including
- Serializing JSON responses directly in SQL
- Data validation
- Authorization
- Combined row counting and retrieval
- Data post in single command (
returning *)
Finally it uses the database efficiently with the Hasql library by
- Keeping a pool of db connections
- Using the PostgreSQL binary protocol
- Being stateless to allow horizontal scaling
Security
PostgREST handles authentication (via JSON Web Tokens) and delegates authorization to the role information defined in the database. This ensures there is a single declarative source of truth for security. When dealing with the database the server assumes the identity of the currently authenticated user, and for the duration of the connection cannot do anything the user themselves couldn't. Other forms of authentication can be built on top of the JWT primitive. See the docs for more information.
Versioning
A robust long-lived API needs the freedom to exist in multiple versions. PostgREST does versioning through database schemas. This allows you to expose tables and views without making the app brittle. Underlying tables can be superseded and hidden behind public facing views.
Self-documentation
PostgREST uses the OpenAPI standard to generate up-to-date documentation for APIs. You can use a tool like Swagger-UI to render interactive documentation for demo requests against the live API server.
This project uses HTTP to communicate other metadata as well. For instance the number of rows returned by an endpoint is reported by - and limited with - range headers. More about that.
Data Integrity
Rather than relying on an Object Relational Mapper and custom imperative coding, this system requires you to put declarative constraints directly into your database. Hence no application can corrupt your data (including your API server).
The PostgREST exposes HTTP interface with safeguards to prevent surprises, such as enforcing idempotent PUT requests.
See examples of PostgreSQL constraints and the API guide.
Supporting development
You can help PostgREST ongoing maintenance and development by making a regular donation through Patreon https://www.patreon.com/postgrest
Every donation will be spent on making PostgREST better for the whole community.
Contributing
Contributions are always welcome and appreciated. Please see the Contributing guidelines.
Thanks
The PostgREST organization is grateful to:
- The project sponsors and backers who support PostgREST's development.
- The project contributors who have improved PostgREST immensely with their code and good judgement. See more details in the changelog.
The cool logo came from Mikey Casalaina.