Learning Apache Cassandra - Second Edition

Partition keys group data on the same node

In Chapter 3, Organizing Related Data, you learned that tables with compound primary keys store all rows sharing the same partition key in contiguous physical storage. This leads to the observation that querying for ranges of clustering column values within a single partition key is highly efficient. To perform this sort of lookup, Cassandra needs to only locate the beginning of the range on disk and can then read all the results beginning at that location. Conversely, querying for rows spanning multiple partition keys requires an inefficient random disk scan for each partition key being queried.

You new understanding of data partitioning expands this observation: you now know that querying for multiple ...