fix: stop reading latest manifest #1365
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rust/lance/src/io/commit.rs
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| // That avoids a HEAD request later. | ||
| let mut manifest_files = object_store | ||
| .inner | ||
| .list(Some(&base.child(VERSIONS_DIR))) |
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this might take a long time if the dataset has a lot of versions.
Maybe we could try something like this?
- read
_latest.manifest - use the version in
_latest.manifestas the start - if we hit a version like
xxxx9999, list from10000000and keep going until we find the latest manifest.
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nvm, i realized reading _latest.manifest is a no starter
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And we can't list from because we aren't zero-padding.
But also see my comment about performance in description.
chebbyChefNEQ
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Oct 5, 2023
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wjones127
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Aug 26, 2024
BREAKING CHANGE: this makes tables written with this and future versions unreadable by Lance v0.8.3 and earlier. We stopped reading this way back in October of last year (#1365). Continuing to write this can actually cause us to hit per-object mutation rate limits in GCS, so we have some reason to stop doing this now.
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As a quick fix to address safety/consistency issues, we will find the latest manifest by scanning the
_versionsdirectory.We continue to write the
_latest.manifestfile, so older readers are still compatible.Performance considerations: in object stores like S3, we can get 1,000 objects listed with 1 request. So right now this adds 1 IO for those tables. Tables with more versions should probably have
cleanup_old_versionsapplied.Fixes: #1356
We will optimize this in follow ups, as described in #1362