By introducing the Text abstraction, we can keep (long) text fields in their UTF8 bytes format, and no need to convert them to a string when serializing it back to Json for example.
The first place we can apply this is to highlighted text, which can be long.. . This does breaks backward comp. for people using the Java API where the HighlightField now has a Text as its content, and not String.
First phase at improving buffer management and reducing even further buffer copies. Introduce a BytesReference abstraction, allowing to more easily slice and "read/write references" from streams. This is the foundation for later using it to create smarter buffers on top of composite netty channels for example (which http now produces) as well as reducing buffer copies when sending transport/rest responses.
Allow the use of "doc" as the update source when a script is not
specified. New fields are added, existing fields are overwritten, and
maps are merged recursively.
When a node restarts, it might be canceling one recovery of a shard id only to get another one in the next cycle. We should detect this case and handle it properly.
This is a fix to the annoying message seen by users: suspect illegal state: trying to move shard from primary mode to replica mode.
Two main changes:
Improve cluster resiliency to disconnected sub clusters. If a node pings a master and that node is no longer registered with the master, improve the rejoin process of that node to the cluster. Also, if a master receives a message from another master, pick one to force to rejoin the cluster (based on cluster state versioning).
On quick rolling restart, without waiting for shard allocation, the shard allocation logic can mess up its counts, causing for strange logic in allocating shards, or validation failures on routing table allocation.
Compressing the stored fields file (the .fdt file) directly allows to have better compression on the size of the index, specifically when indexing (and storing) small documents. The compression will be considerably more effective compared to compressing each doc on its own (when setting compress on the _source mapper). The downside is that more data needs to be uncompressed when loading documents.
The settings to control it is `index.store.compress.stored_fields` set to `true` (it defaults to `false`), and can be enabled dynamically using the update settings API. This allows to enabled compression at a later stage (i.e. old time based indices), and then optimize the index to make sure it gets compressed.
