oxidecomputer / oxidecomputer/omicron
Audit and possibly update compression codecs for ClickHouse data
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- Dominant language
- Rust
- Stars
- 572
- Forks
- 97
- Avg merge
- 2d 12h
- Merged PRs (30d)
- 96
Description
We're currently using the default compression codecs for all metric data in ClickHouse, which is LZ4 on the data blocks on disk. This is probably good for most cases, but particularly for numeric data, it is possible to do much better. There are a number of codecs tailored for numeric data, most notably double delta and Gorilla. We should investigate these, and, if they offer significant savings over the default LZ4, we should switch to them.
Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Start with the ClickHouse compression codec documentation linked in the issue and inspect how metric data currently uses the default LZ4 codec. Compare LZ4 with double delta and Gorilla for the numeric data, then determine whether the savings are significant enough to justify switching codecs. Done means the comparison is documented and any beneficial codec change is applied.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- clickhouse
- Domain
- databases, performance
- Issue type
- Refactor
- Difficulty
- 5/5
- Estimated time
- Over a week
- Activity status
- Stale
- Clarity
- Mostly clear
- Newbie friendliness
- 25/100