tursodatabase / tursodatabase/libsql
Verify bottomless WAL checksumming algorithm
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- Dominant language
- C
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Description
Description of the original SQLite WAL checksumming algorithm: https://www.sqlite.org/fileformat.html#checksum_algorithm
Now, our checksumming implementation is here: https://github.com/tursodatabase/libsql/blob/508ee178007106f9862172ba894500b476b6da85/bottomless/src/wal.rs#L244
Two things I find confusing:
- The original algorithm computes the checksum either in little-endian or big-endian, depending on a value from the WAL header. I don't see any such distinction in our implementation, so maybe we have an assumption that doesn't always hold?
- The function above is named
checksum_be, but I don't see how it uses big-endian and not just host endianness. Can somebody clarify?
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
Read the SQLite checksum algorithm specification and compare it with bottomless/src/wal.rs around line 244, focusing on the WAL-header endianness choice and the checksum_be function. Done means establishing whether the implementation matches the specified algorithm and documenting or addressing any discrepancy found.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- rust
- Domain
- databases
- Issue type
- Bug
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Stale
- Clarity
- Mostly clear
- Newbie friendliness
- 35/100