Update breaking changes for completion suggester

To indicate we removed completion payload option
in favour of returning document source with
completion suggestions
This commit is contained in:
Areek Zillur 2016-08-25 15:42:55 -04:00
parent 5a48ad661d
commit c869ca18eb
1 changed files with 36 additions and 25 deletions

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@ -25,35 +25,46 @@ to suggestion entries for both context and completion suggesters.
==== Completion suggester is document-oriented ==== Completion suggester is document-oriented
Suggestions are aware of the document they belong to. This enables Suggestions are aware of the document they belong to. Now, associated
retrieving any field value from the document. This is exposed documents (`_source`) are returned as part of `completion` suggestions.
through the query-time `payload` option in `completion` and `context`
suggesters:
[source,sh] WARNING: `_source` meta-field must be enabled, which is the default behavior,
--------------- to enable returning `_source` with suggestions.
GET /my_index/_search
{
"suggest": {
"fooSuggestion": {
"text": "f"
"completion": {
"field": "fooSuggest",
"payload": ["field1", "field2"]
}
}
}
}
---------------
Previously, `context` and `completion` suggesters supported an index-time Previously, `context` and `completion` suggesters supported an index-time
`payloads` option, which was used to store and return metadata with suggestions. `payloads` option, which was used to store and return metadata with suggestions.
Now metadata can be stored as a field in the same document as the Now metadata can be stored as part of the the same document as the
suggestion for enabling retrieval at query-time. The support for suggestion for retrieval at query-time. The support for index-time `payloads`
index-time `payloads` has been removed to avoid bloating the in-memory has been removed to avoid bloating the in-memory index with suggestion metadata.
index with suggestion metadata. The time that it takes to retrieve payloads
depends heavily on the size of the `_source` field. The smaller the `_source`, In case of completion queries spanning more than one shard, the suggest is executed
the faster the retrieval. in two phases, where the last phase fetches the relevant documents from shards,
implying executing completion requests against a single shard is more performant
due to the document fetch overhead when the suggest spans multiple shards.
To get best performance for completions, it is recommended to index completions
into a single shard index. In case of high heap usage due to shard size, it is still
recommended to break index into multiple shards instead of optimizing for completion
performance.
Completion results return the full document `_source` by default. The size of
the `_source` can impact performance due to disk fetch and network transport overhead.
For best performance, filter out unnecessary fields from the `_source` using
<<search-request-source-filtering, source filtering>> to minimize `_source` size.
The following demonstrates an example completion query with source filtering:
[source,js]
--------------------------------------------------
POST music/_suggest
{
"_source": "completion.*",
"song-suggest" : {
"prefix" : "nir",
"completion" : {
"field" : "suggest"
}
}
}
--------------------------------------------------
==== Simpler completion indexing ==== Simpler completion indexing