* Compaction: Fetch segments one at a time on main task; skip when possible.
Compact tasks include the ability to fetch existing segments and determine
reasonable defaults for granularitySpec, dimensionsSpec, and metricsSpec.
This is a useful feature that makes compact tasks work well even when the
user running the compaction does not have a clear idea of what they want
the compacted segments to be like.
However, this comes at a cost: it takes time, and disk space, to do all
of these fetches. This patch improves the situation in two ways:
1) When segments do need to be fetched, download them one at a time and
delete them when we're done. This still takes time, but minimizes the
required disk space.
2) Don't fetch segments on the main compact task when they aren't needed.
If the user provides a full granularitySpec, dimensionsSpec, and
metricsSpec, we can skip it.
* Adjustments.
* Changes from code review.
* Fix logic for determining rollup.
* Various documentation updates.
1) Split out "data management" from "ingestion". Break it into thematic pages.
2) Move "SQL-based ingestion" into the Ingestion category. Adjust content so
all conceptual content is in concepts.md and all syntax content is in reference.md.
Shorten the known issues page to the most interesting ones.
3) Add SQL-based ingestion to the ingestion method comparison page. Remove the
index task, since index_parallel is just as good when maxNumConcurrentSubTasks: 1.
4) Rename various mentions of "Druid console" to "web console".
5) Add additional information to ingestion/partitioning.md.
6) Remove a mention of Tranquility.
7) Remove a note about upgrading to Druid 0.10.1.
8) Remove no-longer-relevant task types from ingestion/tasks.md.
9) Move ingestion/native-batch-firehose.md to the hidden section. It was previously deprecated.
10) Move ingestion/native-batch-simple-task.md to the hidden section. It is still linked in some
places, but it isn't very useful compared to index_parallel, so it shouldn't take up space
in the sidebar.
11) Make all br tags self-closing.
12) Certain other cosmetic changes.
13) Update to node-sass 7.
* make travis use node12 for docs
Co-authored-by: Vadim Ogievetsky <vadim@ogievetsky.com>
Gian Merlino