cassandra-glossary

See also cassandra-organized-conceptual-glossary

cassandra-glossary#glossary

• column

  • page 221: each key points to another map of key-value pairs called columns (#)
  • page 221: all columns for a key is stored together, physically, making it inexpensive to access ranges of columns (#)
  • page 221: columns can differ from key to key (#)
  • page 222: columns are sorted (#)
  • page 223: because the columns are ordered and stored together, slice operations over a range of columns are very efficient. (#)
  • Cassandra can store up to 2 billion columns per row, but if we're storing data every millisecond you wouldn't even get a month's worth of data (#)

• column family

  • Page 221: column family is analogous to tables in relation ab databases (#)
  • page 222: schemas only have to be created once per column family (#)

• clustered columns

  • slice: A set of clustered columns in a partition that you query as a set using, for example, a conditional WHERE clause. (#)

• clustering

  • Clustering is a storage engine process that sorts data within the partition. (#)

• key

  • page 221: if you consider a column family a giant map, keys are the top-level entries in that map (#)
  • page 221: cassandra uses keys to partition a column family across a cluster (#)
  • page 221: each key points to another map of key-value pairs called columns (#)
  • can partition keys randomly or preserve order (#)

• keyspace

  • Cassandra has the concept of a keyspace, which is similar to a database in a RDBMS. A keyspace holds data objects and is the level where you specify options for a data partitioning and replication strategy. (#)

• partition key

  • The partition key determines which node stores the data. It is responsible for data distribution across the nodes (#)

• row

  • Cassandra can store up to 2 billion columns per row, but if we're storing data every millisecond you wouldn't even get a month's worth of data (#)

• schema

  • page 222: schemas only have to be created once per column family (#)

• secondary index

  • In Cassandra, if you want to query columns other than the primary key, you need to create a secondary index on them (#)
  • (for a high-cardinality column) It would probably be more efficient to manually maintain the table as a form of an index instead of using the Cassandra built-in index (#)

• slice

  • page 223: because the columns are ordered and stored together, slice operations over a range of columns are very efficient. (#)
  • slice: A set of clustered columns in a partition that you query as a set using, for example, a conditional WHERE clause. (#)

• timeuuid

  • timeuuid: ideal for use in applications requiring conflict-free timestamps (#)

cassandra-glossary#glossary

Referring Pages