How does it work ? SASI (SSTable attached secondary indexes)


Hello Cassandra Developer,

          Today, we will talk about how does indexes work into Cassandra, mainly about SASI.

Motivation factor :
  • It's help you to fulltext search 
  • It's can be get by secondary index on cassandra columns
  • it's help you to get unpredicate search query on cassandra data model 
How does it work (SSTable - secondary indexes): 


  •  Maintain complete indexes data into single SSTable(kind of concurrent thread safe map collection in java)
  • Since it's single SSTable, it has memory issue and need good RAM when huge data.
  • it's called as "Classic C* Indexes"
  • Support few basic comparison operation ("=").
  • It's based on SSTable format.
  • Support into Cassandra older version (less than 3.3)
  • SSTable need to play with memory & disk operation for indexes data.
How does it work (SASI):
  • Maintain the Token tree base format - (B tree collection concept in java)
  • It's create the different separate SASI for each indexes , each index would have separate file i mean.
  • Since it's sets of small chunk/dataset, search performance faster
  •  Support into Cassandra version(3.4)
  • Complete index data built into memory and then store into disk for normal cases
  • Support Inequality & intersect scan operation too (look image)


Below is quick comparison chart :



New Operation support into SASI as below 


Enjoying cassandra coding and data modelling ...

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