arrow

Issue Description

I think we should improve the doc strings in parser.py to be more descriptive and similar like the rest of Arrow.

For feature engineering tasks, I'd like to be able to determine whether a datetime is the beginning or end of a year, like I can in pandas.

import pandas as pd
​
s = pd.Series(["2021-02-27", "2020-03-31"], dtype="datetime64[ms]")
s.dt.is_year_end
0    False
1    False
dtype: bool

import pandas as pd
​
s = pd.Series(["2021-01-01", "2020-04-01"], dtype="datet

sin, cos, etc.

In rust this is not needed as we can easily call apply(_cast)

We no longer need to control the number of concurrent kernels, since now we control the number of concurrent tasks

This is already supported by upstream arrow crate, just need to invoke the relevant API.

Problem description

Reading a dataset with eager's read functionality raises a ValueError when providing columns.

Example code (ideally copy-pastable)

import pandas as pd

from tempfile import TemporaryDirectory
from functools import partial
from storefact import get_store_from_url

from kartothek.io.eager import store_dataframes_as_dataset, read_dataset_as_data

It would be helpful to have Fletchgen output warnings for unused metadata fields that start with fletcher_. For example, (this happened to me) when someone adds fletchgen_epc to Schema metadata instead of Field metadata.

use https://crates.io/crates/rustc-hash rather than the old unmaintained fxhash crate.