influxdata/influxdb · error · PartitionHashIdError

Could not interpret bytes as `PartitionHashId

Error message

Could not interpret bytes as `PartitionHashId`: {data:?}

What it means

This error is returned when a byte slice cannot be interpreted as a `PartitionHashId`, the hashed form of a partition key used internally for partition identification. The library throws it because the byte representation must match the expected structure/length of a `PartitionHashId`; any other bytes are rejected at construction time rather than silently producing a bogus identifier. The offending bytes are attached in the `data` field for diagnosis.

Solutions

  1. Inspect the `data` field of the error and verify the byte length matches what `PartitionHashId` expects for the current library version
  2. Regenerate the hash from the original `PartitionKey` via the library's hashing API instead of reusing stored raw bytes
  3. Check for version mismatch between the code producing the bytes (catalog, parquet files, WAL) and this library version; upgrade/migrate consistently
  4. Validate the storage/serialization path for truncation or corruption before calling the conversion

Example fix

// before
let bytes: Vec<u8> = partition_key.as_bytes().to_vec(); // raw key, not hashed
let hash_id = PartitionHashId::try_from(bytes)?;
// after
let hash_id = PartitionHashId::from_parts(sorted_key_parts); // let the library build the hash
Defensive patterns

Strategy: validation

Validate before calling

fn is_plausible_hash_id(bytes: &[u8]) -> bool {
    // must be non-empty and match the expected encoded hash length
    !bytes.is_empty() && bytes.len() == EXPECTED_PARTITION_HASH_LEN
}
let hash_id = if is_plausible_hash_id(&raw) {
    PartitionHashId::try_from(raw.to_vec()).ok()
} else { None };

Type guard

fn as_partition_hash_id(bytes: &[u8]) -> Option<PartitionHashId> {
    PartitionHashId::try_from(bytes.to_vec()).ok()
}

Try / catch

match PartitionHashId::try_from(bytes) {
    Ok(id) => /* use id */,
    Err(PartitionHashIdError::InvalidBytes { data }) => {
        eprintln!("bad partition hash bytes ({:?}): regenerate from partition key", data);
        // re-derive hash from the original PartitionKey or skip the record
    }
}

Prevention

When it happens

Trigger: Calling `PartitionHashId::try_from(&[u8])` / `TryFrom<Vec<u8>>` (or deserialization paths that convert raw bytes into a `PartitionHashId`) with a byte vector whose length or layout does not match a valid hashed partition identifier.

Common situations: Restoring or importing data from a different version whose partition-hash encoding changed; hand-editing or corrupting catalog/parquet metadata that stores the hash bytes; passing a partition key name instead of its hashed bytes; truncated or concatenated byte buffers read from storage.

Understand the failure class

Background: "Invalid ... format", "must be in format X", "does not look like a ..." — invalid argument format errors across CLI tools and libraries — this error's family across 17 libraries.

Related errors

AI-assisted analysis of influxdata/influxdb@06200ef96b (2026-09-19). Data as JSON: /api/errors/66378617b78b71da. Report an issue: GitHub.

Appendix: source

Thrown at core/data_types/src/partition.rs:369

        // https://github.com/rust-lang/rust/issues/90091
        //
        // So we implement this the hard way (to avoid some nasty panic paths that are quite expensive within a hash function).
        // Conversion borrowed from https://github.com/rust-lang/rfcs/issues/1833#issuecomment-269509262
        const N_BYTES: usize = u64::BITS as usize / 8;

        const _: () = assert!(PARTITION_HASH_ID_SIZE_BYTES >= N_BYTES);
        let ptr = self.0.as_ptr() as *const [u8; N_BYTES];
        let sub: &[u8; N_BYTES] = unsafe { &*ptr };

        state.write_u64(u64::from_ne_bytes(*sub));
    }
}

/// Reasons bytes specified aren't a valid `PartitionHashId`.
#[derive(Debug, Error)]
pub enum PartitionHashIdError {
    /// The bytes specified were not valid
    #[error("Could not interpret bytes as `PartitionHashId`: {data:?}")]
    InvalidBytes {
        /// The bytes used in the attempt to create a `PartitionHashId`
        data: Vec<u8>,
    },
}

impl TryFrom<&[u8]> for PartitionHashId {
    type Error = PartitionHashIdError;

    fn try_from(data: &[u8]) -> Result<Self, Self::Error> {
        let data: [u8; PARTITION_HASH_ID_SIZE_BYTES] =
            data.try_into()
                .map_err(|_| PartitionHashIdError::InvalidBytes {
                    data: data.to_vec(),
                })?;

        Ok(Self(Arc::new(data)))
    }

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