Anatoly Myachev

PERF-#4711: avoid `to_pandas` call when calling left join

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Signed-off-by: Anatoly Myachev ## What do these changes do? Key idea: the current implementation for left join can be replaced with a combination of `right.reindex` + `concat` functions. This approach...

PERF-#4777: Don't use `copy=True` parameter for `concat` calls inside `to_pandas`

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Signed-off-by: Myachev ## What do these changes do? - [ ] commit message follows format outlined [here](https://modin.readthedocs.io/en/latest/development/contributing.html#commit-message-formatting) - [ ] passes `flake8 modin/ asv_bench/benchmarks scripts/doc_checker.py` - [ ] passes `black...

PERF: `_propagate_index_objs` can be implemented to compute caches

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Place: https://github.com/modin-project/modin/blob/aeff7ac70162b53f8c6178f048498c2ee9bd631b/modin/core/dataframe/pandas/dataframe/dataframe.py#L515 Most likely, we will have to change the interface of `add_to_apply_calls` function so that it passes caches to the partition constructor.

Place: https://github.com/modin-project/modin/blob/ef654c414364ca319812114324ad9d85e83ee68e/modin/core/io/file_dispatcher.py#L165 Would be great to find out another solution here to not block IO operations. At least we can return `dtypes` as `lengths` and `widths` from remote functions.

Signed-off-by: Myachev ## What do these changes do? - [ ] commit message follows format outlined [here](https://modin.readthedocs.io/en/latest/development/contributing.html#commit-message-formatting) - [ ] passes `flake8 modin/ asv_bench/benchmarks scripts/doc_checker.py` - [ ] passes `black...

PERF-#2814: Call 'get' on all partitions at once in 'to_pandas'

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Signed-off-by: Myachev ## What do these changes do? - [ ] commit message follows format outlined [here](https://modin.readthedocs.io/en/latest/development/contributing.html#commit-message-formatting) - [ ] passes `flake8 modin/ asv_bench/benchmarks scripts/doc_checker.py` - [ ] passes `black...

Places: https://github.com/modin-project/modin/blob/a28e319d9756c9383afa9efd67e32eb04e6b848c/modin/core/dataframe/pandas/partitioning/partition_manager.py#L657 and https://github.com/modin-project/modin/blob/a28e319d9756c9383afa9efd67e32eb04e6b848c/modin/core/dataframe/pandas/utils.py#L48

FIX-#4680: fix `read_csv` that started defaulting to pandas again in case of reading from a buffer and when a buffer has a non-zero starting position

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Signed-off-by: Myachev ## What do these changes do? - [x] commit message follows format outlined [here](https://modin.readthedocs.io/en/latest/development/contributing.html#commit-message-formatting) - [x] passes `flake8 modin/ asv_bench/benchmarks scripts/doc_checker.py` - [x] passes `black --check modin/ asv_bench/benchmarks...

FIX-#4660: Fix `fillna` when Modin series object is an argument

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Signed-off-by: Myachev ## What do these changes do? - [x] commit message follows format outlined [here](https://modin.readthedocs.io/en/latest/development/contributing.html#commit-message-formatting) - [x] passes `flake8 modin/ asv_bench/benchmarks scripts/doc_checker.py` - [x] passes `black --check modin/ asv_bench/benchmarks...