Async support for tile endpoint

[jr-elliott]

In the tile endpoint, particularly L914, I've been trying to understand if this read (say from S3) is async or not. I've looked through gdal discussion, rasterio issues, etc, but I haven't been able to put all the pieces together.

Can anyone say if this particular part is async or not?

[vincentsarago]

GDAL is not async everything is synchronous

FastAPI is smart and sync endpoint will be put into a thread to be run asynchronously which is how FastAPI can handle many requests

[jr-elliott]

Thanks for the clarification. I see in Titiler that the tiles endpoint is sync. However in our implementation, we need to make a database call to find the right COG to process. We made that call async, and thus made our tile endpoint async, but that's not playing well with GDAL. Do you have any recommendations here? Do we need to manually put the GDAL parts into a separate thread now?

[vincentsarago]

have you check titiler-pgstac or titiler-stacapi ?

We made that call async, and thus made our tile endpoint async, but that's not playing well with GDAL

I would say that you should change the call to the database to be sync (then FastAPI will make it asynchronous). It's better not to mix asynchronous and synchronous.

We are working on building an async COG Reader but we need more funding to speed up the process, please feel free to reach out Developmentseed if you or your company want to help 🙏

[jr-elliott]

have you check titiler-pgstac or titiler-stacapi ?

We've moved to pgstac for our ongoing work, but don't have the time/budget to move our previous work from titiler to pgstac. The new projects are great though, thank you for all your work on them.

I would say that you should change the call to the database to be sync (then FastAPI will make it asynchronous). It's better not to mix asynchronous and synchronous.

Ok this makes sense. We would still need an async database engine, right? And just the calls to conn.execute won't include an await?

We are working on building an async COG Reader but we need more funding to speed up the process, please feel free to reach out Developmentseed if you or your company want to help 🙏

Is this async-tiff?

[vincentsarago]

Ok this makes sense. We would still need an async database engine, right? And just the calls to conn.execute won't include an await?

Depends what you're using to connect to your Postgres database, checkout titiler-pgstac to see how we do it

Is this async-tiff?

Yes