One more bit which might be relevant in this context: there is a
work-in-progress patch https://gerrit.cloudera.org/#/c/10983/ addressing
KUDU-1291. That's not secondary indices per se, but that might help in
some cases where the prefix component of the primary key is of low
cardinality.
On Thu,
Secondary indexing is a feature request that comes up fairly often.
KUDU-2613 is the tracking JIRA, but there's no real content in there.
Better to look at KUDU-2038, for which there's a work in progress
patch for bitmap indexing (https://gerrit.cloudera.org/c/11722/) that
you can also follow.
