[fs] expose hl.fast_stat and hl.hadoop_fast_stat to users #13886
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added 3 commits
October 23, 2023 10:45
CHANGELOG: Hail Query-on-Batch previously used Class A Operations for all interaction with blobs. This change ensures that QoB only uses Class A Operations when necessary. Inspired by @jigold 's file system improvement campaign, I pursued the avoidance of "list" operations. I anticipate this reduces flakiness in Azure (which is tracked in hail-is#13351) and cost in Azure. I enforced aiotools.fs terminology on hail.fs and Scala: 1. `FileStatus`. Metadata about a blob or file. It does not know if a directory exists at this path. 2. `FileListEntry`. Metadata from a list operation. It knows if a directory exists at this path. Variable names were updated to reflect this distinction: 1. `fileStatus` / `fileStatuses` 2. `fle`/ `fles` / `fileListEntry` / `fileListEntries`, respectively. `listStatus` renamed to `listDirectory` for clarity. In both Azure and Google, `fileStatus` does not use a list operation. `fileListEntry` can be used when we must know if a directory exists. I just rewrote this from first principles because: 1. In neither Google nor Azure did it check if the path was a directory and a file. 2. In Google, if the directory entry wasn't in the first page, it would fail (NB: there are fifteen non-control characters in ASCII before `/`, if the page size is 15 or fewer, we'd miss the first entry with a `/` at the end). 3. In Azure, we issued both a get and a list. There are now unit tests for this method. --- 1. `copyMerge` and `concatenateFiles` previously used `O(N_FILES)` list operations, they now use `O(N_FILES)` get operations. 2. Writers that used `exists` to check for a _SUCCESS file now use a get operation. 3. Index readers, import BGEN, and import plink all now check file size with a get operation. That said, overall, the bulk of our Class A Operations are probably writes.
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added 4 commits
October 23, 2023 12:29
CHANGELOG: Introduce `hl.fs.fast_stat` and `hl.hadoop_fast_stat` which use cheaper Class B Operations in Google Cloud Storage rather than Class A Operations. Users of `hl.hadoop_stat` and `hl.fs.stat` should consider switching. This PR extends hail-is#13885 into the public API.
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CHANGELOG: Introduce
hl.fs.fast_statandhl.hadoop_fast_statwhich use cheaper Class B Operations in Google Cloud Storage rather than Class A Operations. Users ofhl.hadoop_statandhl.fs.statshould consider switching.This PR extends #13885 into the public API.