[CASSANDRA-4175] Reduce memory, disk space, and cpu usage with a column name/id map

• Type: Improvement
• Status: Resolved
• Priority: Normal
• Resolution: Duplicate
• Labels: performance
• Assignee: Unassigned Assign to me
• Reporter: Jonathan Ellis
• Created: 19/Apr/12 21:39
• Updated: 16/Apr/19 09:32
• Resolved: 11/Aug/15 16:37

Description

We spend a lot of memory on column names, both transiently (during reads) and more permanently (in the row cache). Compression mitigates this on disk but not on the heap.

The overhead is significant for typical small column values, e.g., ints.

Even though we intern once we get to the memtable, this affects writes too via very high allocation rates in the young generation, hence more GC activity.

Now that CQL3 provides us some guarantees that column names must be defined before they are inserted, we could create a map of (say) 32-bit int column id, to names, and use that internally right up until we return a resultset to the client.

Issue Links

• is duplicated by: CASSANDRA-7070 Virtual column name aliasing
• is related to: CASSANDRA-8099 Refactor and modernize the storage engine