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d699dc3c77
Fix language in docs and comments --------- Signed-off-by: Arve Knudsen <arve.knudsen@gmail.com> Co-authored-by: Björn Rabenstein <github@rabenste.in>
2.6 KiB
2.6 KiB
Head Chunks on Disk Format
The following describes the format of a chunks file, which is created in the
chunks_head/ directory inside the data directory.
Chunks in the files are referenced from the index by uint64 composed of in-file offset (lower 4 bytes) and segment sequence number (upper 4 bytes).
┌──────────────────────────────┐
│ magic(0x0130BC91) <4 byte> │
├──────────────────────────────┤
│ version(1) <1 byte> │
├──────────────────────────────┤
│ padding(0) <3 byte> │
├──────────────────────────────┤
│ ┌──────────────────────────┐ │
│ │ Chunk 1 │ │
│ ├──────────────────────────┤ │
│ │ ... │ │
│ ├──────────────────────────┤ │
│ │ Chunk N │ │
│ └──────────────────────────┘ │
└──────────────────────────────┘
Chunk
Unlike chunks in the on-disk blocks, here we additionally store the series reference that each chunk belongs to and the mint/maxt of the chunks. This is because we don't have an index associated with these chunks, hence this metadata is used while replaying the chunks.
┌─────────────────────┬───────────────────────┬───────────────────────┬───────────────────┬───────────────┬──────────────┬────────────────┐
| series ref <8 byte> | mint <8 byte, uint64> | maxt <8 byte, uint64> | encoding <1 byte> | len <uvarint> | data <bytes> │ CRC32 <4 byte> │
└─────────────────────┴───────────────────────┴───────────────────────┴───────────────────┴───────────────┴──────────────┴────────────────┘