feat: add the 1st draft for JEP-3

docs/chapters/jep/jep-3/index.yml

@@ -0,0 +1,41 @@
+!Flow
+with:
+  board:
+    canvas:
+      gateway:
+        x: 528
+        y: 71
+      FieldsMapper:
+        x: 527
+        y: 199
+      TitleFilteredEncoder:
+        x: 377
+        y: 344
+      SumFilteredEncoder:
+        x: 665
+        y: 334
+      TitleIndexer:
+        x: 366
+        y: 539
+      SumIndexer:
+        x: 660
+        y: 539
+      join:
+        x: 516
+        y: 659
+pods:
+  gateway: {}
+  FieldsMapper:
+    needs: gateway
+  TitleFilteredEncoder:
+    needs: FieldsMapper
+  SumFilteredEncoder:
+    needs: FieldsMapper
+  TitleIndexer:
+    needs: TitleFilteredEncoder
+  SumIndexer:
+    needs: SumFilteredEncoder
+  join:
+    needs:
+      - TitleIndexer
+      - SumIndexer

docs/chapters/jep/jep-3/main.rst

@@ -0,0 +1,133 @@
+JEP 1 --- Adding support for multi-fields search
+=================================================================
+
+.. contents:: Table of Contents
+   :depth: 3
+
+
+:Author: Nan Wang (nan.wang@jina.ai)
+:Created: May. 28, 2020
+:Status: Proposal
+:Related JEPs:
+:Created on Jina VCS version: ``TBA``
+:Merged to Jina VCS version: ``TBA``
+:Released in Jina version: TBA
+:Discussions: https://github.com/jina-ai/jina/issues/441
+
+.. contents:: Table of Contents
+   :depth: 2
+
+Abstract
+--------
+
+[A short (~200 word) description of the technical issue being addressed.]
+
+Motivation
+---------
+Multi-field search is commonly used in the production.
+Concretely, the use case is to limit the query within some fields that the user has selected.
+In the following case, there are three two fields in each document, i.e. ``title`` and ``summary``.
+The use case is to query only from the ``title`` field. Given the query, ``q='painter'``,
+the expected result is only ``hacker and painters``.
+
+.. highlight:: json
+.. code-block:: json
+    {
+      "id": 10,
+      "title": "the story of the art",
+      "summary": "This is a book about the history of the art, and the stories of the great painters"
+    }, {
+      "id": 11,
+      "title": "hackers and painters",
+      "summary": "This book discusses hacking, start-up companies, and many other technological issues"
+    }
+
+
+Rationale
+---------
+The core issue of this use case is the need of marking the ``Chunks`` from different fields.
+During the query time, we would like to enable the users to change the selected fields in different queries without rebuilding the query ``Flow``.
+
+.. highlight:: json
+.. code-block:: json
+    {
+        "data": "painter",
+        "top_k": 10,
+        "mime_type": "application/text"
+        "fields_name": ["title"],
+    }
+
+Flow
+^^^^
+
+.. image:: JEP3-index-design.png
+   :align: center
+   :width: 60%
+
+To achieve this, we propose the following changes,
+
+1. Add a new field in the protobuf defination of the ``Chunk``.
+
+.. highlight:: proto
+.. code-block:: proto
+    message Chunk {
+        ...
+        string field_name = 13;
+    }
+
+2. Add a new ``Crafter`` for adding ``field_name`` information to the ``Chunk``.
+
+.. highlight:: python
+.. code-block:: python
+    class FieldMapper(BaseSegmenter):
+        def craft(self, *args, **kwargs) -> List[Dict]:
+            pass
+
+.. highlight:: python
+.. code-block:: python
+    class MapperDriver(SegmentDriver):
+        pass
+
+3. Add a new ``Driver`` for merging the messages defined by ``field_names`` in the request instead of merging all the messages defined by ``needs``.
+
+
+4. Add a CompoundExecutor, namely ``FieldEncoder``, which wraps up ``FieldMapper`` and ``Encoder`` as a common pattern for multi-field search.
+
+.. highlight:: yaml
+.. code-block:: yaml
+    !FieldEncoder
+    on:
+        SearchRequest, IndexRequest:
+            - !MapperDriver:
+                with:
+                    executor: FieldMapper
+            - !EncoderDriver
+                with:
+                    executor: TransformerTFEncoder
+
+
+Specification
+-------------
+
+[Describe the syntax and semantics of any new feature.]
+
+Backwards Compatibility
+-----------------------
+
+[Describe potential impact and severity on pre-existing code.]
+
+
+Reference Implementation
+------------------------
+
+[Link to any existing implementation and details about its state, e.g. proof-of-concept.]
+
+Open Issues
+-----------
+
+[Any points that are still being decided/discussed.]
+
+References
+----------
+
+[A collection of URLs used as references through the JEP.]

docs/chapters/jep/jep-3/query.yml

@@ -0,0 +1,46 @@
+!Flow
+with:
+  board:
+    canvas:
+      gateway:
+        x: 528
+        y: 71
+      FieldsMapper:
+        x: 526
+        y: 162
+      TitleFilteredEncoder:
+        x: 333
+        y: 280
+      SumFilteredEncoder:
+        x: 676
+        y: 262
+      TitleIndexer:
+        x: 332
+        y: 404
+      SumIndexer:
+        x: 669
+        y: 394
+      join:
+        x: 507
+        y: 535
+      ranker:
+        x: 505
+        y: 635
+pods:
+  gateway: {}
+  FieldsMapper:
+    needs: gateway
+  TitleFilteredEncoder:
+    needs: FieldsMapper
+  SumFilteredEncoder:
+    needs: FieldsMapper
+  TitleIndexer:
+    needs: TitleFilteredEncoder
+  SumIndexer:
+    needs: SumFilteredEncoder
+  join:
+    needs:
+      - TitleIndexer
+      - SumIndexer
+  ranker:
+    needs: join