d4967c38f8
* 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>
1.8 KiB
| id | title |
|---|---|
| schema-changes | Schema changes |
For new data
Apache Druid allows you to provide a new schema for new data without the need to update the schema of any existing data. It is sufficient to update your supervisor spec, if using streaming ingestion, or to provide the new schema the next time you do a batch ingestion. This is made possible by the fact that each segment, at the time it is created, stores a copy of its own schema. Druid reconciles all of these individual segment schemas automatically at query time.
For existing data
Schema changes are sometimes necessary for existing data. For example, you may want to change the type of a column in previously-ingested data, or drop a column entirely. Druid handles this using reindexing, the same method it uses to handle updates of existing data. Reindexing involves rewriting all affected segments and can be a time-consuming operation.