Added without_files flag to DeltaTable constructor

[MykhailoHevak]

Description

Added without_files flag to DeltaTable constructor. If the flag is set it will be called method without_files in the DeltaTableBuilder. And this allows users to control memory usage. Some append-only applications might have no need of tracking any files.

Documentation

Indicates whether DeltaTable should not track files. This defaults to "false" (files are tracked). Some append-only applications might have no need of tracking any files. So, DeltaTable will be loaded with significant memory reduction.

[wjones127]

Thanks for submitting this! I have a few suggested changes.

What's the behavior of DeltaTable.file_uris() when without_files=True? Does it return empty? Or raise an error? Or load the files? We might want to add a unit test for that in Python.

[wjones127]

What's the behavior of DeltaTable.file_uris() when without_files=True? Does it return empty? Or raise an error? Or load the files? We might want to add a unit test for that in Python.

Just checked and it returns an empty list. We should document that for now, and consider changing that behavior in the future (#867).

[wjones127]

@MykhailoHevak looks like the merge you pushed overwrote the changes you accepted in the GitHub UI. Could you add those back?

[MykhailoHevak]

@MykhailoHevak looks like the merge you pushed overwrote the changes you accepted in the GitHub UI. Could you add those back?

Oooops... I did it accidentally. Is it OK now?

[wjones127]

Oooops... I did it accidentally. Is it OK now?

The docstring change is still missing.

[MykhailoHevak]

Do I have to do something else?

[wjones127]

Thanks @MykhailoHevak!

[danielvrog]

@wjones127 is there an estimation on when the new release is planned?
Thanks

P.S. closes #860

[dennyglee]

Hey @MykhailoHevak I believe this is your first PR to the delta repo. Can you ping me (dennyglee) via the Delta Users slack so we can send you some swag? Thanks!