THIS IS A TEST INSTANCE. ALL YOUR CHANGES WILL BE LOST!!!!
...
- Row ID - A monotonic increasing integer associated with every row in a sstable. It’s stored in an index structure instead of key token or key offset, because it compresses better.
- Postings/posting-list - Sorted row ids that match a given indexed value.
- Token file - An index of Row ID -> partition key token for every row in the sstable.
- Offset file - An index of Row ID -> partition key offset on the data/primary-index file for every row in the sstable.
- Segment - A smallest unit of on-disk indexing structure that is flushed during compaction to reduce memory pressure. Multiple segments of an index are written to the same physical file.
...
Index Format Version 1
SAI is optimised for storage. Tokens and offsets are stored once per SSTable. Column indexes access the token and offset files using a row ID. Offsets are compressed using Frame of Reference (FoR) encoding while tokens are not because tokens consume the full 8 bytes and therefore cannot be compressed.
...