Gian Merlino 2be7068f6e Fixes and improvements to SQL metadata caching. (#4551) ...

* Fixes and improvements to SQL metadata caching.

Also adds support for MultipleSpecificSegmentSpec to CachingClusteredClient.

SQL changes:
- Cache metadata on a per-segment level, in addition to per-dataSource, so
  we don't need to re-query all segments whenever a single new one appears.
  This should lower the load placed on the cluster by metadata queries.
- Fix race condition in DruidSchema that can cause us to miss metadata. It was
  possible to notice new segments, then issue a query, and have that query
  not actually hit those segments, and not notice that it didn't hit those segments.
  Then, the metadata from those segments would be ignored.
- Fix assumption in DruidSchema that all segments are immutable. Now, mutable
  segments are periodically re-queried.
- Fix inappropriate re-use of SchemaPlus. Now we create one for each planning
  cycle, rather than sharing one. It caches table objects, which we want to
  avoid, since it can cause stale metadata. We do the caching in DruidSchema
  so we don't need the SchemaPlus caching.

Server changes:
- Add a TimelineCallback to TimelineServerView, for callers that want to get updates
  when the timeline has been modified.
- Change CachingClusteredClient from a QueryRunner to a QuerySegmentWalker. This
  allows it to accept queries that are segment-descriptor-based rather than
  intervals-based. In particular it will now support MultipleSpecificSegmentSpec.

* Fix DruidSchema, and unused imports.

* Remove unused import.

* Fix SqlBenchmark.

2017-07-20 10:14:15 -07:00

..

src

Fixes and improvements to SQL metadata caching. (#4551)

2017-07-20 10:14:15 -07:00

pom.xml

Update versions to 0.11.0-SNAPSHOT (#4483)

2017-06-28 17:05:58 -07:00