perf(blooms): Remove compression of .tar
archived bloom blocks
#14159
+376
−224
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What this PR does / why we need it:
Decompression is a CPU intensive task, especially un-gzipping. The gain of compressing a tar archive of storage optimized binary blocks is neglectable (question: is it?).
In this example, the block of ~170MiB is ~3.3MiB bigger when not compressed, which is a ratio of ~2%
Breaking change
This is less of an issue, because there has not been a release of the new structured metatada blooms yet. Anyone using a Loki version frommain
after commit a2fbaa8 is affected.Special notes for your reviewer:
CPU profile from a time period where blocks have been downloaded and extracted.
Further discussion:
Adding the correct file type extension as suffix to the key in object storage makes any change to compression a breaking change, unless the GetBlock() call tries multiple different keys with different suffixes. That could be a rather hacky option to keep backwards compatibility, but it also introduces more complexity in various areas whenever the Addr() of a BlockRef needs to be resolved.
Another option would be to additionally store the compression algorithm into the BlockRef struct.
Update
After some consideration, we decided to store the encoding of the bloom block in the
BlockRef
. This means, that the changes in this PR do not break compatibility with existing blocks compressed with gzip, although new blocks will not be compressed any more.However, the PR adds support for different compression algorithms, such as gzip, snappy, lz4, flate, and zstd. Compression is not configurable yet.
Checklist
CONTRIBUTING.md
guide (required)feat
PRs are unlikely to be accepted unless a case can be made for the feature actually being a bug fix to existing behavior.docs/sources/setup/upgrade/_index.md
production/helm/loki/Chart.yaml
and updateproduction/helm/loki/CHANGELOG.md
andproduction/helm/loki/README.md
. Example PRdeprecated-config.yaml
anddeleted-config.yaml
files respectively in thetools/deprecated-config-checker
directory. Example PR