Which 3 data structures is supported by SS table from the below ?
- Bloom Filter
- Partition table
- Parititon Index
- Partition Summary
The Bloom filter is a data structure that helps determine the probability that an SSTable contains partition data. Serialised bloom filter of the partition keys are stored in the *-Filter.db component of the SSTables which get read into off-heap memory.
The partition index contains the index of partition keys in an SSTable and their corresponding offset or pointers to their position in the SSTable. The partition index is stored on disk in the *-Index.db component of the SSTables and is cached in off-heap memory as the partition key cache.
The partition summary is a sample (subset) of the partition index used to optimise reads. The partition summary is stored on disk in the *-Summary.db component of the SSTables which get read into off-heap memory.
"Partition table" is not a SSTable data structure.
These structures are discussed in more detail in How data is read in Cassandra. Cheers!
@ashok.dcosta_187920 Cassandra processes data at several stages on the read path to discover where the data is stored, starting with the data in the memtable and finishing with SSTables:
Some of the stages checked are memtable,Bloom filter,partition key ,partition summary.
For more information please refer to Cassandra Read Path
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