Vespa 向量存储演示

如果您在 Colab 上打开这个笔记本，您可能需要安装 LlamaIndex 🦙。

%pip install llama-index-vector-stores-vespa llama-index pyvespa

设置API密钥

import os
import openai

os.environ["OPENAI_API_KEY"] = "sk-..."
openai.api_key = os.environ["OPENAI_API_KEY"]

加载文档，构建向量存储索引

from llama_index.core import VectorStoreIndex
from llama_index.vector_stores.vespa import VespaVectorStore
from IPython.display import Markdown, display

定义一些示例数据

让我们插入一些文档。

from llama_index.core.schema import TextNode

nodes = [
    TextNode(
        text="The Shawshank Redemption",
        metadata={
            "author": "Stephen King",
            "theme": "Friendship",
            "year": 1994,
        },
    ),
    TextNode(
        text="The Godfather",
        metadata={
            "director": "Francis Ford Coppola",
            "theme": "Mafia",
            "year": 1972,
        },
    ),
    TextNode(
        text="Inception",
        metadata={
            "director": "Christopher Nolan",
            "theme": "Fiction",
            "year": 2010,
        },
    ),
    TextNode(
        text="To Kill a Mockingbird",
        metadata={
            "author": "Harper Lee",
            "theme": "Mafia",
            "year": 1960,
        },
    ),
    TextNode(
        text="1984",
        metadata={
            "author": "George Orwell",
            "theme": "Totalitarianism",
            "year": 1949,
        },
    ),
    TextNode(
        text="The Great Gatsby",
        metadata={
            "author": "F. Scott Fitzgerald",
            "theme": "The American Dream",
            "year": 1925,
        },
    ),
    TextNode(
        text="Harry Potter and the Sorcerer's Stone",
        metadata={
            "author": "J.K. Rowling",
            "theme": "Fiction",
            "year": 1997,
        },
    ),
]

初始化 VespaVectorStore

为了让入门变得非常简单，我们提供了一个模板Vespa应用程序，该程序将在初始化向量存储时部署。

这是一个巨大的抽象层，有无限的机会可以根据您的需求来定制和调整 Vespa 应用程序。但现在，让我们保持简单，使用默认模板进行初始化。

from llama_index.core import StorageContext

vector_store = VespaVectorStore()
storage_context = StorageContext.from_defaults(vector_store=vector_store)
index = VectorStoreIndex(nodes, storage_context=storage_context)

删除文档

node_to_delete = nodes[0].node_id
node_to_delete

vector_store.delete(ref_doc_id=node_to_delete)

查询

from llama_index.core.vector_stores.types import (
    VectorStoreQuery,
    VectorStoreQueryMode,
)

query = VectorStoreQuery(
    query_str="Great Gatsby",
    mode=VectorStoreQueryMode.TEXT_SEARCH,
    similarity_top_k=1,
)
result = vector_store.query(query)

result

作为检索器

默认查询模式（文本搜索）

retriever = index.as_retriever(vector_store_query_mode="default")
results = retriever.retrieve("Who directed inception?")
display(Markdown(f"**Retrieved nodes:**\n {results}"))

retriever = index.as_retriever(vector_store_query_mode="semantic_hybrid")
results = retriever.retrieve("Who wrote Harry Potter?")
display(Markdown(f"**Retrieved nodes:**\n {results}"))

作为查询引擎

query_engine = index.as_query_engine()
response = query_engine.query("Who directed inception?")
display(Markdown(f"**Response:** {response}"))

query_engine = index.as_query_engine(
    vector_store_query_mode="semantic_hybrid", verbose=True
)
response = query_engine.query(
    "When was the book about the wizard boy published and what was it called?"
)
display(Markdown(f"**Response:** {response}"))
display(Markdown(f"**Sources:** {response.source_nodes}"))

使用元数据过滤器

注意: 此元数据过滤由llama-index执行，在vespa外部完成。如需使用原生且性能更优的过滤功能，您应当使用Vespa自身的过滤能力。

更多信息请参阅 Vespa 文档。

from llama_index.core.vector_stores import (
    FilterOperator,
    FilterCondition,
    MetadataFilter,
    MetadataFilters,
)

# Let's define a filter that will only allow nodes that has the theme "Fiction" OR is published after 1997

filters = MetadataFilters(
    filters=[
        MetadataFilter(key="theme", value="Fiction"),
        MetadataFilter(key="year", value=1997, operator=FilterOperator.GT),
    ],
    condition=FilterCondition.OR,
)

retriever = index.as_retriever(filters=filters)
result = retriever.retrieve("Harry Potter")
display(Markdown(f"**Result:** {result}"))

此集成的抽象层级

为了让入门变得非常简单，我们提供了一个模板Vespa应用程序，该程序将在初始化向量存储时部署。这消除了首次设置Vespa时的一些复杂性，但对于严肃的使用场景，我们强烈建议您阅读Vespa文档并根据您的需求定制应用程序。

模板

提供的Vespa应用模板如下所示：

from vespa.package import (
    ApplicationPackage,
    Field,
    Schema,
    Document,
    HNSW,
    RankProfile,
    Component,
    Parameter,
    FieldSet,
    GlobalPhaseRanking,
    Function,
)

hybrid_template = ApplicationPackage(
    name="hybridsearch",
    schema=[
        Schema(
            name="doc",
            document=Document(
                fields=[
                    Field(name="id", type="string", indexing=["summary"]),
                    Field(name="metadata", type="string", indexing=["summary"]),
                    Field(
                        name="text",
                        type="string",
                        indexing=["index", "summary"],
                        index="enable-bm25",
                        bolding=True,
                    ),
                    Field(
                        name="embedding",
                        type="tensor<float>(x[384])",
                        indexing=[
                            "input text",
                            "embed",
                            "index",
                            "attribute",
                        ],
                        ann=HNSW(distance_metric="angular"),
                        is_document_field=False,
                    ),
                ]
            ),
            fieldsets=[FieldSet(name="default", fields=["text", "metadata"])],
            rank_profiles=[
                RankProfile(
                    name="bm25",
                    inputs=[("query(q)", "tensor<float>(x[384])")],
                    functions=[Function(name="bm25sum", expression="bm25(text)")],
                    first_phase="bm25sum",
                ),
                RankProfile(
                    name="semantic",
                    inputs=[("query(q)", "tensor<float>(x[384])")],
                    first_phase="closeness(field, embedding)",
                ),
                RankProfile(
                    name="fusion",
                    inherits="bm25",
                    inputs=[("query(q)", "tensor<float>(x[384])")],
                    first_phase="closeness(field, embedding)",
                    global_phase=GlobalPhaseRanking(
                        expression="reciprocal_rank_fusion(bm25sum, closeness(field, embedding))",
                        rerank_count=1000,
                    ),
                ),
            ],
        )
    ],
    components=[
        Component(
            id="e5",
            type="hugging-face-embedder",
            parameters=[
                Parameter(
                    "transformer-model",
                    {
                        "url": "https://github.com/vespa-engine/sample-apps/raw/master/simple-semantic-search/model/e5-small-v2-int8.onnx"
                    },
                ),
                Parameter(
                    "tokenizer-model",
                    {
                        "url": "https://raw.githubusercontent.com/vespa-engine/sample-apps/master/simple-semantic-search/model/tokenizer.json"
                    },
                ),
            ],
        )
    ],
)

请注意，字段 id、metadata、text 和 embedding 是集成工作所必需的。模式名称也必须为 doc，并且排名配置文件必须命名为 bm25、semantic 和 fusion。

除此之外，您可以根据需要自由修改，例如更换嵌入模型、添加更多字段或更改排序表达式。

更多详细信息，请查看这个关于混合搜索的Pyvespa示例笔记本。