Timescale Vector (PostgreSQL)

Timescale Vector 是 PostgreSQL++ 用于 AI 应用的向量数据库。

本笔记本展示了如何使用 Postgres 向量数据库 Timescale Vector。您将了解如何使用 TimescaleVector 进行 (1) 语义搜索、(2) 基于时间的向量搜索、(3) 自查询以及 (4) 如何创建索引以加速查询。

什么是 Timescale Vector？

Timescale Vector 使您能够在 PostgreSQL 中高效地存储和查询数百万个向量嵌入。

通过 DiskANN 启发的索引算法，增强了 pgvector，在 1 亿多个向量上进行更快、更准确的相似性搜索。
通过自动基于时间的分区和索引，实现快速基于时间的向量搜索。
提供熟悉的 SQL 接口用于查询向量嵌入和关系数据。

Timescale Vector 是用于 AI 的云 PostgreSQL，它可以随您从概念验证扩展到生产环境

通过使您能够将关系元数据、向量嵌入和时间序列数据存储在单个数据库中，简化了操作。
从坚如磐石的 PostgreSQL 基础受益，具有企业级功能，如流式备份和复制、高可用性和行级安全性。
通过企业级安全性和合规性，实现无忧体验。

如何访问 Timescale Vector

Timescale Vector 在 Timescale 上可用，它是云 PostgreSQL 平台。（目前没有自托管版本。）

LangChain 用户可以获得 Timescale Vector 的 90 天免费试用。

要开始，请注册 Timescale，创建一个新数据库，然后按照本笔记本操作！
请参阅 Timescale Vector 解释性博客以了解详细信息和性能基准。
请参阅安装说明以了解有关在 Python 中使用 Timescale Vector 的更多详细信息。

设置

按照以下步骤准备好学习本教程。

# Pip install necessary packages
%pip install --upgrade --quiet  timescale-vector
%pip install --upgrade --quiet  langchain-openai langchain-community
%pip install --upgrade --quiet  tiktoken

在本例中，我们将使用 OpenAIEmbeddings，因此让我们加载您的 OpenAI API 密钥。

import os

# Run export OPENAI_API_KEY=sk-YOUR_OPENAI_API_KEY...
# Get openAI api key by reading local .env file
from dotenv import find_dotenv, load_dotenv

_ = load_dotenv(find_dotenv())
OPENAI_API_KEY = os.environ["OPENAI_API_KEY"]

# Get the API key and save it as an environment variable
# import os
# import getpass
# os.environ["OPENAI_API_KEY"] = getpass.getpass("OpenAI API Key:")

from typing import Tuple

接下来，我们将导入所需的 Python 库和 LangChain 库。请注意，我们将导入 timescale-vector 库以及 TimescaleVector LangChain 向量存储。

from datetime import datetime, timedelta

from langchain_community.document_loaders import TextLoader
from langchain_community.document_loaders.json_loader import JSONLoader
from langchain_community.vectorstores.timescalevector import TimescaleVector
from langchain_core.documents import Document
from langchain_openai import OpenAIEmbeddings
from langchain_text_splitters import CharacterTextSplitter

1. 使用欧几里得距离（默认）进行相似性搜索

首先，我们将查看对国情咨文进行相似性搜索查询的示例，以查找与给定查询句子最相似的句子。我们将使用欧几里得距离作为我们的相似性度量。

# Load the text and split it into chunks
loader = TextLoader("../../../extras/modules/state_of_the_union.txt")
documents = loader.load()
text_splitter = CharacterTextSplitter(chunk_size=1000, chunk_overlap=0)
docs = text_splitter.split_documents(documents)

embeddings = OpenAIEmbeddings()

接下来，我们将加载 Timescale 数据库的服务 URL。

如果您尚未这样做，请注册 Timescale，并创建一个新数据库。

然后，要连接到您的 PostgreSQL 数据库，您将需要您的服务 URI，该 URI 可在创建新数据库后下载的速查表或 .env 文件中找到。

URI 的外观类似于：postgres://tsdbadmin:<password>@<id>.tsdb.cloud.timescale.com:<port>/tsdb?sslmode=require。

# Timescale Vector needs the service url to your cloud database. You can see this as soon as you create the
# service in the cloud UI or in your credentials.sql file
SERVICE_URL = os.environ["TIMESCALE_SERVICE_URL"]

# Specify directly if testing
# SERVICE_URL = "postgres://tsdbadmin:<password>@<id>.tsdb.cloud.timescale.com:<port>/tsdb?sslmode=require"

# # You can get also it from an environment variables. We suggest using a .env file.
# import os
# SERVICE_URL = os.environ.get("TIMESCALE_SERVICE_URL", "")

接下来，我们创建一个 TimescaleVector 向量存储。我们将指定一个集合名称，该名称将是我们数据存储在其中的表的名称。

注意：在创建 TimescaleVector 的新实例时，TimescaleVector 模块将尝试创建一个名称为集合的表。因此，请确保集合名称是唯一的（即它不存在）。

# The TimescaleVector Module will create a table with the name of the collection.
COLLECTION_NAME = "state_of_the_union_test"

# Create a Timescale Vector instance from the collection of documents
db = TimescaleVector.from_documents(
    embedding=embeddings,
    documents=docs,
    collection_name=COLLECTION_NAME,
    service_url=SERVICE_URL,
)

现在我们已经加载了数据，我们可以执行相似性搜索。

query = "What did the president say about Ketanji Brown Jackson"
docs_with_score = db.similarity_search_with_score(query)

for doc, score in docs_with_score:
    print("-" * 80)
    print("Score: ", score)
    print(doc.page_content)
    print("-" * 80)

--------------------------------------------------------------------------------
Score:  0.18443380687035138
Tonight. I call on the Senate to: Pass the Freedom to Vote Act. Pass the John Lewis Voting Rights Act. And while you’re at it, pass the Disclose Act so Americans can know who is funding our elections. 

Tonight, I’d like to honor someone who has dedicated his life to serve this country: Justice Stephen Breyer—an Army veteran, Constitutional scholar, and retiring Justice of the United States Supreme Court. Justice Breyer, thank you for your service. 

One of the most serious constitutional responsibilities a President has is nominating someone to serve on the United States Supreme Court. 

And I did that 4 days ago, when I nominated Circuit Court of Appeals Judge Ketanji Brown Jackson. One of our nation’s top legal minds, who will continue Justice Breyer’s legacy of excellence.
--------------------------------------------------------------------------------
--------------------------------------------------------------------------------
Score:  0.18452197313308139
Tonight. I call on the Senate to: Pass the Freedom to Vote Act. Pass the John Lewis Voting Rights Act. And while you’re at it, pass the Disclose Act so Americans can know who is funding our elections. 

Tonight, I’d like to honor someone who has dedicated his life to serve this country: Justice Stephen Breyer—an Army veteran, Constitutional scholar, and retiring Justice of the United States Supreme Court. Justice Breyer, thank you for your service. 

One of the most serious constitutional responsibilities a President has is nominating someone to serve on the United States Supreme Court. 

And I did that 4 days ago, when I nominated Circuit Court of Appeals Judge Ketanji Brown Jackson. One of our nation’s top legal minds, who will continue Justice Breyer’s legacy of excellence.
--------------------------------------------------------------------------------
--------------------------------------------------------------------------------
Score:  0.21720781018594182
A former top litigator in private practice. A former federal public defender. And from a family of public school educators and police officers. A consensus builder. Since she’s been nominated, she’s received a broad range of support—from the Fraternal Order of Police to former judges appointed by Democrats and Republicans. 

And if we are to advance liberty and justice, we need to secure the Border and fix the immigration system. 

We can do both. At our border, we’ve installed new technology like cutting-edge scanners to better detect drug smuggling.  

We’ve set up joint patrols with Mexico and Guatemala to catch more human traffickers.  

We’re putting in place dedicated immigration judges so families fleeing persecution and violence can have their cases heard faster. 

We’re securing commitments and supporting partners in South and Central America to host more refugees and secure their own borders.
--------------------------------------------------------------------------------
--------------------------------------------------------------------------------
Score:  0.21724902288621384
A former top litigator in private practice. A former federal public defender. And from a family of public school educators and police officers. A consensus builder. Since she’s been nominated, she’s received a broad range of support—from the Fraternal Order of Police to former judges appointed by Democrats and Republicans. 

And if we are to advance liberty and justice, we need to secure the Border and fix the immigration system. 

We can do both. At our border, we’ve installed new technology like cutting-edge scanners to better detect drug smuggling.  

We’ve set up joint patrols with Mexico and Guatemala to catch more human traffickers.  

We’re putting in place dedicated immigration judges so families fleeing persecution and violence can have their cases heard faster. 

We’re securing commitments and supporting partners in South and Central America to host more refugees and secure their own borders.
--------------------------------------------------------------------------------

使用 Timescale Vector 作为检索器

初始化 TimescaleVector 存储后，您可以将其用作检索器。

# Use TimescaleVector as a retriever
retriever = db.as_retriever()

print(retriever)

tags=['TimescaleVector', 'OpenAIEmbeddings'] metadata=None vectorstore=<langchain_community.vectorstores.timescalevector.TimescaleVector object at 0x10fc8d070> search_type='similarity' search_kwargs={}

让我们看一个使用 Timescale Vector 作为检索器以及检索 QA 链和内容文档链的示例。

在本例中，我们将提出与上面相同的查询，但这次我们将从 Timescale Vector 返回的相关文档传递给 LLM，以用作回答我们问题的上下文。

首先，我们将创建内容链

# Initialize GPT3.5 model
from langchain_openai import ChatOpenAI

llm = ChatOpenAI(temperature=0.1, model="gpt-3.5-turbo-16k")

# Initialize a RetrievalQA class from a stuff chain
from langchain.chains import RetrievalQA

qa_stuff = RetrievalQA.from_chain_type(
    llm=llm,
    chain_type="stuff",
    retriever=retriever,
    verbose=True,
)

API 参考：ChatOpenAI | RetrievalQA

query = "What did the president say about Ketanji Brown Jackson?"
response = qa_stuff.run(query)

[1m> Entering new RetrievalQA chain...[0m

[1m> Finished chain.[0m

print(response)

The President said that he nominated Circuit Court of Appeals Judge Ketanji Brown Jackson, who is one of our nation's top legal minds and will continue Justice Breyer's legacy of excellence. He also mentioned that since her nomination, she has received a broad range of support from various groups, including the Fraternal Order of Police and former judges appointed by Democrats and Republicans.

2. 使用基于时间的过滤进行相似性搜索

Timescale Vector 的一个关键用例是高效的基于时间的向量搜索。Timescale Vector 通过自动按时间对向量（以及相关元数据）进行分区来实现这一点。这使您能够通过与查询向量的相似性和时间来高效地查询向量。

基于时间的向量搜索功能对于以下应用非常有用

存储和检索 LLM 响应历史（例如聊天机器人）
查找与查询向量相似的最新嵌入（例如最新新闻）。
将相似性搜索限制在相关时间范围内（例如，提出有关知识库的基于时间的问题）

为了说明如何使用 TimescaleVector 的基于时间的向量搜索功能，我们将提出有关 TimescaleDB 的 git 日志历史记录的问题。我们将说明如何添加具有基于时间的 uuid 的文档以及如何运行具有时间范围过滤器的相似性搜索。

从 git 日志 JSON 中提取内容和元数据

首先，让我们将 git 日志数据加载到 PostgreSQL 数据库中的名为 timescale_commits 的新集合中。

我们将定义一个辅助函数来根据文档的时间戳创建文档和相关向量嵌入的 uuid。我们将使用此函数为每个 git 日志条目创建 uuid。

重要提示：如果您正在使用文档，并且希望将当前日期和时间与向量相关联以进行基于时间的搜索，则可以跳过此步骤。默认情况下，文档被摄取时会自动生成 uuid。

from timescale_vector import client


# Function to take in a date string in the past and return a uuid v1
def create_uuid(date_string: str):
    if date_string is None:
        return None
    time_format = "%a %b %d %H:%M:%S %Y %z"
    datetime_obj = datetime.strptime(date_string, time_format)
    uuid = client.uuid_from_time(datetime_obj)
    return str(uuid)

接下来，我们将定义一个元数据函数，用于从 JSON 记录中提取相关元数据。我们将把此函数传递给 JSONLoader。有关更多详细信息，请参阅JSON 文档加载器文档。

# Helper function to split name and email given an author string consisting of Name Lastname <email>
def split_name(input_string: str) -> Tuple[str, str]:
    if input_string is None:
        return None, None
    start = input_string.find("<")
    end = input_string.find(">")
    name = input_string[:start].strip()
    email = input_string[start + 1 : end].strip()
    return name, email


# Helper function to transform a date string into a timestamp_tz string
def create_date(input_string: str) -> datetime:
    if input_string is None:
        return None
    # Define a dictionary to map month abbreviations to their numerical equivalents
    month_dict = {
        "Jan": "01",
        "Feb": "02",
        "Mar": "03",
        "Apr": "04",
        "May": "05",
        "Jun": "06",
        "Jul": "07",
        "Aug": "08",
        "Sep": "09",
        "Oct": "10",
        "Nov": "11",
        "Dec": "12",
    }

    # Split the input string into its components
    components = input_string.split()
    # Extract relevant information
    day = components[2]
    month = month_dict[components[1]]
    year = components[4]
    time = components[3]
    timezone_offset_minutes = int(components[5])  # Convert the offset to minutes
    timezone_hours = timezone_offset_minutes // 60  # Calculate the hours
    timezone_minutes = timezone_offset_minutes % 60  # Calculate the remaining minutes
    # Create a formatted string for the timestamptz in PostgreSQL format
    timestamp_tz_str = (
        f"{year}-{month}-{day} {time}+{timezone_hours:02}{timezone_minutes:02}"
    )
    return timestamp_tz_str


# Metadata extraction function to extract metadata from a JSON record
def extract_metadata(record: dict, metadata: dict) -> dict:
    record_name, record_email = split_name(record["author"])
    metadata["id"] = create_uuid(record["date"])
    metadata["date"] = create_date(record["date"])
    metadata["author_name"] = record_name
    metadata["author_email"] = record_email
    metadata["commit_hash"] = record["commit"]
    return metadata

接下来，您需要下载示例数据集并将其放置到与本笔记本相同的目录中。

您可以使用以下命令

# Download the file using curl and save it as commit_history.csv
# Note: Execute this command in your terminal, in the same directory as the notebook
!curl -O https://s3.amazonaws.com/assets.timescale.com/ai/ts_git_log.json

最后，我们可以初始化 JSON 加载器来解析 JSON 记录。为简化起见，我们还删除了空记录。

# Define path to the JSON file relative to this notebook
# Change this to the path to your JSON file
FILE_PATH = "../../../../../ts_git_log.json"

# Load data from JSON file and extract metadata
loader = JSONLoader(
    file_path=FILE_PATH,
    jq_schema=".commit_history[]",
    text_content=False,
    metadata_func=extract_metadata,
)
documents = loader.load()

# Remove documents with None dates
documents = [doc for doc in documents if doc.metadata["date"] is not None]

print(documents[0])

page_content='{"commit": "44e41c12ab25e36c202f58e068ced262eadc8d16", "author": "Lakshmi Narayanan Sreethar<[email protected]>", "date": "Tue Sep 5 21:03:21 2023 +0530", "change summary": "Fix segfault in set_integer_now_func", "change details": "When an invalid function oid is passed to set_integer_now_func, it finds out that the function oid is invalid but before throwing the error, it calls ReleaseSysCache on an invalid tuple causing a segfault. Fixed that by removing the invalid call to ReleaseSysCache.  Fixes #6037 "}' metadata={'source': '/Users/avtharsewrathan/sideprojects2023/timescaleai/tsv-langchain/ts_git_log.json', 'seq_num': 1, 'id': '8b407680-4c01-11ee-96a6-b82284ddccc6', 'date': '2023-09-5 21:03:21+0850', 'author_name': 'Lakshmi Narayanan Sreethar', 'author_email': '[email protected]', 'commit_hash': '44e41c12ab25e36c202f58e068ced262eadc8d16'}

将文档和元数据加载到 TimescaleVector 向量存储中

现在我们已经准备好了文档，让我们处理它们并将它们连同它们的向量嵌入表示一起加载到我们的 TimescaleVector 向量存储中。

由于这是一个演示，我们将只加载前 500 条记录。在实际应用中，您可以根据需要加载任意数量的记录。

NUM_RECORDS = 500
documents = documents[:NUM_RECORDS]

然后，我们使用 CharacterTextSplitter 将文档拆分成更小的块（如果需要），以便更容易进行嵌入。请注意，此拆分过程保留了每个文档的元数据。

# Split the documents into chunks for embedding
text_splitter = CharacterTextSplitter(
    chunk_size=1000,
    chunk_overlap=200,
)
docs = text_splitter.split_documents(documents)

接下来，我们将从完成预处理的文档集合中创建一个 Timescale Vector 实例。

首先，我们将定义一个集合名称，它将是我们在 PostgreSQL 数据库中的表的名称。

我们还将定义一个时间增量，将其传递给 time_partition_interval 参数，该参数将用作按时间对数据进行分区的时间间隔。每个分区将包含指定时间段内的数据。为了简单起见，我们将使用 7 天，但您可以根据自己的用例选择任何有意义的值——例如，如果您经常查询最近的向量，您可能希望使用更小的时间增量（如 1 天），或者如果您查询超过十年的时间段内的向量，那么您可能希望使用更大的时间增量（如 6 个月或 1 年）。

最后，我们将创建 TimescaleVector 实例。我们将 ids 参数指定为我们在上面预处理步骤中创建的元数据中的 uuid 字段。我们这样做是因为我们希望 uuid 的时间部分反映过去的时间（即提交的时间）。但是，如果我们希望当前日期和时间与我们的文档相关联，我们可以删除 id 参数，uuid 将自动使用当前日期和时间创建。

# Define collection name
COLLECTION_NAME = "timescale_commits"
embeddings = OpenAIEmbeddings()

# Create a Timescale Vector instance from the collection of documents
db = TimescaleVector.from_documents(
    embedding=embeddings,
    ids=[doc.metadata["id"] for doc in docs],
    documents=docs,
    collection_name=COLLECTION_NAME,
    service_url=SERVICE_URL,
    time_partition_interval=timedelta(days=7),
)

按时间和相似度查询向量

现在我们已经将文档加载到 TimescaleVector 中，我们可以按时间和相似度查询它们。

TimescaleVector 提供了多种方法，可以通过执行基于时间的过滤的相似度搜索来查询向量。

让我们看一下下面的每种方法

# Time filter variables
start_dt = datetime(2023, 8, 1, 22, 10, 35)  # Start date = 1 August 2023, 22:10:35
end_dt = datetime(2023, 8, 30, 22, 10, 35)  # End date = 30 August 2023, 22:10:35
td = timedelta(days=7)  # Time delta = 7 days

query = "What's new with TimescaleDB functions?"

方法 1：在提供的开始日期和结束日期内进行过滤。

# Method 1: Query for vectors between start_date and end_date
docs_with_score = db.similarity_search_with_score(
    query, start_date=start_dt, end_date=end_dt
)

for doc, score in docs_with_score:
    print("-" * 80)
    print("Score: ", score)
    print("Date: ", doc.metadata["date"])
    print(doc.page_content)
    print("-" * 80)

--------------------------------------------------------------------------------
Score:  0.17488396167755127
Date:  2023-08-29 18:13:24+0320
{"commit": " e4facda540286b0affba47ccc63959fefe2a7b26", "author": "Sven Klemm<[email protected]>", "date": "Tue Aug 29 18:13:24 2023 +0200", "change summary": "Add compatibility layer for _timescaledb_internal functions", "change details": "With timescaledb 2.12 all the functions present in _timescaledb_internal were moved into the _timescaledb_functions schema to improve schema security. This patch adds a compatibility layer so external callers of these internal functions will not break and allow for more flexibility when migrating. "}
--------------------------------------------------------------------------------
--------------------------------------------------------------------------------
Score:  0.18102192878723145
Date:  2023-08-20 22:47:10+0320
{"commit": " 0a66bdb8d36a1879246bd652e4c28500c4b951ab", "author": "Sven Klemm<[email protected]>", "date": "Sun Aug 20 22:47:10 2023 +0200", "change summary": "Move functions to _timescaledb_functions schema", "change details": "To increase schema security we do not want to mix our own internal objects with user objects. Since chunks are created in the _timescaledb_internal schema our internal functions should live in a different dedicated schema. This patch make the necessary adjustments for the following functions:  - to_unix_microseconds(timestamptz) - to_timestamp(bigint) - to_timestamp_without_timezone(bigint) - to_date(bigint) - to_interval(bigint) - interval_to_usec(interval) - time_to_internal(anyelement) - subtract_integer_from_now(regclass, bigint) "}
--------------------------------------------------------------------------------
--------------------------------------------------------------------------------
Score:  0.18150119891755445
Date:  2023-08-22 12:01:19+0320
{"commit": " cf04496e4b4237440274eb25e4e02472fc4e06fc", "author": "Sven Klemm<[email protected]>", "date": "Tue Aug 22 12:01:19 2023 +0200", "change summary": "Move utility functions to _timescaledb_functions schema", "change details": "To increase schema security we do not want to mix our own internal objects with user objects. Since chunks are created in the _timescaledb_internal schema our internal functions should live in a different dedicated schema. This patch make the necessary adjustments for the following functions:  - generate_uuid() - get_git_commit() - get_os_info() - tsl_loaded() "}
--------------------------------------------------------------------------------
--------------------------------------------------------------------------------
Score:  0.18422493887617963
Date:  2023-08-9 15:26:03+0500
{"commit": " 44eab9cf9bef34274c88efd37a750eaa74cd8044", "author": "Konstantina Skovola<[email protected]>", "date": "Wed Aug 9 15:26:03 2023 +0300", "change summary": "Release 2.11.2", "change details": "This release contains bug fixes since the 2.11.1 release. We recommend that you upgrade at the next available opportunity.  **Features** * #5923 Feature flags for TimescaleDB features  **Bugfixes** * #5680 Fix DISTINCT query with JOIN on multiple segmentby columns * #5774 Fixed two bugs in decompression sorted merge code * #5786 Ensure pg_config --cppflags are passed * #5906 Fix quoting owners in sql scripts. * #5912 Fix crash in 1-step integer policy creation  **Thanks** * @mrksngl for submitting a PR to fix extension upgrade scripts * @ericdevries for reporting an issue with DISTINCT queries using segmentby columns of compressed hypertable "}
--------------------------------------------------------------------------------

请注意，查询仅返回指定日期范围内的结果。

方法 2：在提供的开始日期和之后的时间增量内进行过滤。

# Method 2: Query for vectors between start_dt and a time delta td later
# Most relevant vectors between 1 August and 7 days later
docs_with_score = db.similarity_search_with_score(
    query, start_date=start_dt, time_delta=td
)

for doc, score in docs_with_score:
    print("-" * 80)
    print("Score: ", score)
    print("Date: ", doc.metadata["date"])
    print(doc.page_content)
    print("-" * 80)

--------------------------------------------------------------------------------
Score:  0.18458807468414307
Date:  2023-08-3 14:30:23+0500
{"commit": " 7aeed663b9c0f337b530fd6cad47704a51a9b2ec", "author": "Dmitry Simonenko<[email protected]>", "date": "Thu Aug 3 14:30:23 2023 +0300", "change summary": "Feature flags for TimescaleDB features", "change details": "This PR adds several GUCs which allow to enable/disable major timescaledb features:  - enable_hypertable_create - enable_hypertable_compression - enable_cagg_create - enable_policy_create "}
--------------------------------------------------------------------------------
--------------------------------------------------------------------------------
Score:  0.20492422580718994
Date:  2023-08-7 18:31:40+0320
{"commit": " 07762ea4cedefc88497f0d1f8712d1515cdc5b6e", "author": "Sven Klemm<[email protected]>", "date": "Mon Aug 7 18:31:40 2023 +0200", "change summary": "Test timescaledb debian 12 packages in CI", "change details": ""}
--------------------------------------------------------------------------------
--------------------------------------------------------------------------------
Score:  0.21106326580047607
Date:  2023-08-3 14:36:39+0500
{"commit": " 2863daf3df83c63ee36c0cf7b66c522da5b4e127", "author": "Dmitry Simonenko<[email protected]>", "date": "Thu Aug 3 14:36:39 2023 +0300", "change summary": "Support CREATE INDEX ONLY ON main table", "change details": "This PR adds support for CREATE INDEX ONLY ON clause which allows to create index only on the main table excluding chunks.  Fix #5908 "}
--------------------------------------------------------------------------------
--------------------------------------------------------------------------------
Score:  0.21698051691055298
Date:  2023-08-2 20:24:14+0140
{"commit": " 3af0d282ea71d9a8f27159a6171e9516e62ec9cb", "author": "Lakshmi Narayanan Sreethar<[email protected]>", "date": "Wed Aug 2 20:24:14 2023 +0100", "change summary": "PG16: ExecInsertIndexTuples requires additional parameter", "change details": "PG16 adds a new boolean parameter to the ExecInsertIndexTuples function to denote if the index is a BRIN index, which is then used to determine if the index update can be skipped. The fix also removes the INDEX_ATTR_BITMAP_ALL enum value.  Adapt these changes by updating the compat function to accomodate the new parameter added to the ExecInsertIndexTuples function and using an alternative for the removed INDEX_ATTR_BITMAP_ALL enum value.  postgres/postgres@19d8e23 "}
--------------------------------------------------------------------------------

再次注意，我们如何获得指定时间过滤器内的结果，这与之前的查询不同。

方法 3：在提供的结束日期和之前的时间增量内进行过滤。

# Method 3: Query for vectors between end_dt and a time delta td earlier
# Most relevant vectors between 30 August and 7 days earlier
docs_with_score = db.similarity_search_with_score(query, end_date=end_dt, time_delta=td)

for doc, score in docs_with_score:
    print("-" * 80)
    print("Score: ", score)
    print("Date: ", doc.metadata["date"])
    print(doc.page_content)
    print("-" * 80)

--------------------------------------------------------------------------------
Score:  0.17488396167755127
Date:  2023-08-29 18:13:24+0320
{"commit": " e4facda540286b0affba47ccc63959fefe2a7b26", "author": "Sven Klemm<[email protected]>", "date": "Tue Aug 29 18:13:24 2023 +0200", "change summary": "Add compatibility layer for _timescaledb_internal functions", "change details": "With timescaledb 2.12 all the functions present in _timescaledb_internal were moved into the _timescaledb_functions schema to improve schema security. This patch adds a compatibility layer so external callers of these internal functions will not break and allow for more flexibility when migrating. "}
--------------------------------------------------------------------------------
--------------------------------------------------------------------------------
Score:  0.18496227264404297
Date:  2023-08-29 10:49:47+0320
{"commit": " a9751ccd5eb030026d7b975d22753f5964972389", "author": "Sven Klemm<[email protected]>", "date": "Tue Aug 29 10:49:47 2023 +0200", "change summary": "Move partitioning functions to _timescaledb_functions schema", "change details": "To increase schema security we do not want to mix our own internal objects with user objects. Since chunks are created in the _timescaledb_internal schema our internal functions should live in a different dedicated schema. This patch make the necessary adjustments for the following functions:  - get_partition_for_key(val anyelement) - get_partition_hash(val anyelement) "}
--------------------------------------------------------------------------------
--------------------------------------------------------------------------------
Score:  0.1871250867843628
Date:  2023-08-28 23:26:23+0320
{"commit": " b2a91494a11d8b82849b6f11f9ea6dc26ef8a8cb", "author": "Sven Klemm<[email protected]>", "date": "Mon Aug 28 23:26:23 2023 +0200", "change summary": "Move ddl_internal functions to _timescaledb_functions schema", "change details": "To increase schema security we do not want to mix our own internal objects with user objects. Since chunks are created in the _timescaledb_internal schema our internal functions should live in a different dedicated schema. This patch make the necessary adjustments for the following functions:  - chunk_constraint_add_table_constraint(_timescaledb_catalog.chunk_constraint) - chunk_drop_replica(regclass,name) - chunk_index_clone(oid) - chunk_index_replace(oid,oid) - create_chunk_replica_table(regclass,name) - drop_stale_chunks(name,integer[]) - health() - hypertable_constraint_add_table_fk_constraint(name,name,name,integer) - process_ddl_event() - wait_subscription_sync(name,name,integer,numeric) "}
--------------------------------------------------------------------------------
--------------------------------------------------------------------------------
Score:  0.18867712088363497
Date:  2023-08-27 13:20:04+0320
{"commit": " e02b1f348eb4c48def00b7d5227238b4d9d41a4a", "author": "Sven Klemm<[email protected]>", "date": "Sun Aug 27 13:20:04 2023 +0200", "change summary": "Simplify schema move update script", "change details": "Use dynamic sql to create the ALTER FUNCTION statements for those functions that may not exist in previous versions. "}
--------------------------------------------------------------------------------

方法 4：我们也可以仅在查询中指定开始日期来过滤给定日期之后的所有向量。

方法 5：类似地，我们可以仅在查询中指定结束日期来过滤给定日期之前的所有向量。

# Method 4: Query all vectors after start_date
docs_with_score = db.similarity_search_with_score(query, start_date=start_dt)

for doc, score in docs_with_score:
    print("-" * 80)
    print("Score: ", score)
    print("Date: ", doc.metadata["date"])
    print(doc.page_content)
    print("-" * 80)

--------------------------------------------------------------------------------
Score:  0.17488396167755127
Date:  2023-08-29 18:13:24+0320
{"commit": " e4facda540286b0affba47ccc63959fefe2a7b26", "author": "Sven Klemm<[email protected]>", "date": "Tue Aug 29 18:13:24 2023 +0200", "change summary": "Add compatibility layer for _timescaledb_internal functions", "change details": "With timescaledb 2.12 all the functions present in _timescaledb_internal were moved into the _timescaledb_functions schema to improve schema security. This patch adds a compatibility layer so external callers of these internal functions will not break and allow for more flexibility when migrating. "}
--------------------------------------------------------------------------------
--------------------------------------------------------------------------------
Score:  0.18102192878723145
Date:  2023-08-20 22:47:10+0320
{"commit": " 0a66bdb8d36a1879246bd652e4c28500c4b951ab", "author": "Sven Klemm<[email protected]>", "date": "Sun Aug 20 22:47:10 2023 +0200", "change summary": "Move functions to _timescaledb_functions schema", "change details": "To increase schema security we do not want to mix our own internal objects with user objects. Since chunks are created in the _timescaledb_internal schema our internal functions should live in a different dedicated schema. This patch make the necessary adjustments for the following functions:  - to_unix_microseconds(timestamptz) - to_timestamp(bigint) - to_timestamp_without_timezone(bigint) - to_date(bigint) - to_interval(bigint) - interval_to_usec(interval) - time_to_internal(anyelement) - subtract_integer_from_now(regclass, bigint) "}
--------------------------------------------------------------------------------
--------------------------------------------------------------------------------
Score:  0.18150119891755445
Date:  2023-08-22 12:01:19+0320
{"commit": " cf04496e4b4237440274eb25e4e02472fc4e06fc", "author": "Sven Klemm<[email protected]>", "date": "Tue Aug 22 12:01:19 2023 +0200", "change summary": "Move utility functions to _timescaledb_functions schema", "change details": "To increase schema security we do not want to mix our own internal objects with user objects. Since chunks are created in the _timescaledb_internal schema our internal functions should live in a different dedicated schema. This patch make the necessary adjustments for the following functions:  - generate_uuid() - get_git_commit() - get_os_info() - tsl_loaded() "}
--------------------------------------------------------------------------------
--------------------------------------------------------------------------------
Score:  0.18422493887617963
Date:  2023-08-9 15:26:03+0500
{"commit": " 44eab9cf9bef34274c88efd37a750eaa74cd8044", "author": "Konstantina Skovola<[email protected]>", "date": "Wed Aug 9 15:26:03 2023 +0300", "change summary": "Release 2.11.2", "change details": "This release contains bug fixes since the 2.11.1 release. We recommend that you upgrade at the next available opportunity.  **Features** * #5923 Feature flags for TimescaleDB features  **Bugfixes** * #5680 Fix DISTINCT query with JOIN on multiple segmentby columns * #5774 Fixed two bugs in decompression sorted merge code * #5786 Ensure pg_config --cppflags are passed * #5906 Fix quoting owners in sql scripts. * #5912 Fix crash in 1-step integer policy creation  **Thanks** * @mrksngl for submitting a PR to fix extension upgrade scripts * @ericdevries for reporting an issue with DISTINCT queries using segmentby columns of compressed hypertable "}
--------------------------------------------------------------------------------

# Method 5: Query all vectors before end_date
docs_with_score = db.similarity_search_with_score(query, end_date=end_dt)

for doc, score in docs_with_score:
    print("-" * 80)
    print("Score: ", score)
    print("Date: ", doc.metadata["date"])
    print(doc.page_content)
    print("-" * 80)

--------------------------------------------------------------------------------
Score:  0.16723191738128662
Date:  2023-04-11 22:01:14+0320
{"commit": " 0595ff0888f2ffb8d313acb0bda9642578a9ade3", "author": "Sven Klemm<[email protected]>", "date": "Tue Apr 11 22:01:14 2023 +0200", "change summary": "Move type support functions into _timescaledb_functions schema", "change details": ""}
--------------------------------------------------------------------------------
--------------------------------------------------------------------------------
Score:  0.1706540584564209
Date:  2023-04-6 13:00:00+0320
{"commit": " 04f43335dea11e9c467ee558ad8edfc00c1a45ed", "author": "Sven Klemm<[email protected]>", "date": "Thu Apr 6 13:00:00 2023 +0200", "change summary": "Move aggregate support function into _timescaledb_functions", "change details": "This patch moves the support functions for histogram, first and last into the _timescaledb_functions schema. Since we alter the schema of the existing functions in upgrade scripts and do not change the aggregates this should work completely transparently for any user objects using those aggregates. "}
--------------------------------------------------------------------------------
--------------------------------------------------------------------------------
Score:  0.17462033033370972
Date:  2023-03-31 08:22:57+0320
{"commit": " feef9206facc5c5f506661de4a81d96ef059b095", "author": "Sven Klemm<[email protected]>", "date": "Fri Mar 31 08:22:57 2023 +0200", "change summary": "Add _timescaledb_functions schema", "change details": "Currently internal user objects like chunks and our functions live in the same schema making locking down that schema hard. This patch adds a new schema _timescaledb_functions that is meant to be the schema used for timescaledb internal functions to allow separation of code and chunks or other user objects. "}
--------------------------------------------------------------------------------
--------------------------------------------------------------------------------
Score:  0.17488396167755127
Date:  2023-08-29 18:13:24+0320
{"commit": " e4facda540286b0affba47ccc63959fefe2a7b26", "author": "Sven Klemm<[email protected]>", "date": "Tue Aug 29 18:13:24 2023 +0200", "change summary": "Add compatibility layer for _timescaledb_internal functions", "change details": "With timescaledb 2.12 all the functions present in _timescaledb_internal were moved into the _timescaledb_functions schema to improve schema security. This patch adds a compatibility layer so external callers of these internal functions will not break and allow for more flexibility when migrating. "}
--------------------------------------------------------------------------------

主要 takeaway 是，在上面的每个结果中，只返回指定时间范围内的向量。这些查询非常有效，因为它们只需要搜索相关的分区。

我们还可以使用此功能进行问答，我们希望在指定时间范围内找到最相关的向量，以便将其用作回答问题的上下文。让我们看一下下面的示例，使用 Timescale Vector 作为检索器

# Set timescale vector as a retriever and specify start and end dates via kwargs
retriever = db.as_retriever(search_kwargs={"start_date": start_dt, "end_date": end_dt})

from langchain_openai import ChatOpenAI

llm = ChatOpenAI(temperature=0.1, model="gpt-3.5-turbo-16k")

from langchain.chains import RetrievalQA

qa_stuff = RetrievalQA.from_chain_type(
    llm=llm,
    chain_type="stuff",
    retriever=retriever,
    verbose=True,
)

query = (
    "What's new with the timescaledb functions? Tell me when these changes were made."
)
response = qa_stuff.run(query)
print(response)

API 参考：ChatOpenAI | RetrievalQA

[1m> Entering new RetrievalQA chain...[0m

[1m> Finished chain.[0m
The following changes were made to the timescaledb functions:

1. "Add compatibility layer for _timescaledb_internal functions" - This change was made on Tue Aug 29 18:13:24 2023 +0200.
2. "Move functions to _timescaledb_functions schema" - This change was made on Sun Aug 20 22:47:10 2023 +0200.
3. "Move utility functions to _timescaledb_functions schema" - This change was made on Tue Aug 22 12:01:19 2023 +0200.
4. "Move partitioning functions to _timescaledb_functions schema" - This change was made on Tue Aug 29 10:49:47 2023 +0200.

请注意，LLM 用于构建答案的上下文仅来自指定日期范围内的检索文档。

这展示了如何使用 Timescale Vector 通过检索与您的查询相关的时间范围内的文档来增强检索增强型生成。

3. 使用 ANN 搜索索引来加速查询

您可以通过在嵌入列上创建索引来加速相似度查询。您应该只在您已经摄取了大部分数据之后再执行此操作。

Timescale Vector 支持以下索引

timescale_vector 索引 (tsv)：一个受磁盘 ann 启发的图索引，用于快速相似度搜索（默认）。
pgvector 的 HNSW 索引：一个用于快速相似度搜索的分层可导航小世界图索引。
pgvector 的 IVFFLAT 索引：一个用于快速相似度搜索的倒排文件索引。

重要提示：在 PostgreSQL 中，每个表只能在特定列上有一个索引。因此，如果您想测试不同索引类型的性能，您可以通过以下方式进行：(1) 创建多个具有不同索引的表，(2) 在同一表中创建多个向量列，并在每个列上创建不同的索引，或者 (3) 通过删除和重新创建相同列上的索引并比较结果来进行。

# Initialize an existing TimescaleVector store
COLLECTION_NAME = "timescale_commits"
embeddings = OpenAIEmbeddings()
db = TimescaleVector(
    collection_name=COLLECTION_NAME,
    service_url=SERVICE_URL,
    embedding_function=embeddings,
)

使用 create_index() 函数，不带任何其他参数将默认创建一个 timescale_vector_index，使用默认参数。

# create an index
# by default this will create a Timescale Vector (DiskANN) index
db.create_index()

您还可以指定索引的参数。有关不同参数及其对性能影响的完整讨论，请参阅 Timescale Vector 文档。

注意：您不需要指定参数，因为我们设置了智能默认值。但是，如果您想尝试一下以获得特定数据集的更高性能，您始终可以指定自己的参数。

# drop the old index
db.drop_index()

# create an index
# Note: You don't need to specify m and ef_construction parameters as we set smart defaults.
db.create_index(index_type="tsv", max_alpha=1.0, num_neighbors=50)

Timescale Vector 还支持 HNSW ANN 索引算法以及 ivfflat ANN 索引算法。只需在 index_type 参数中指定您要创建的索引，并可选择指定索引的参数。

# drop the old index
db.drop_index()

# Create an HNSW index
# Note: You don't need to specify m and ef_construction parameters as we set smart defaults.
db.create_index(index_type="hnsw", m=16, ef_construction=64)

# drop the old index
db.drop_index()

# Create an IVFFLAT index
# Note: You don't need to specify num_lists and num_records parameters as we set smart defaults.
db.create_index(index_type="ivfflat", num_lists=20, num_records=1000)

通常，我们建议使用默认的 timescale 向量索引或 HNSW 索引。

# drop the old index
db.drop_index()
# Create a new timescale vector index
db.create_index()

4. 使用 Timescale Vector 的自查询检索器

Timescale Vector 还支持自查询检索器功能，这使它能够查询自身。给定一个带有查询语句和过滤器（单一或复合）的自然语言查询，检索器使用查询构建 LLM 链来编写 SQL 查询，然后将其应用于 Timescale Vector 向量存储中的基础 PostgreSQL 数据库。

有关自查询的更多信息，请参阅文档。

为了说明使用 Timescale Vector 的自查询，我们将使用第 3 部分中的相同 gitlog 数据集。

COLLECTION_NAME = "timescale_commits"
vectorstore = TimescaleVector(
    embedding_function=OpenAIEmbeddings(),
    collection_name=COLLECTION_NAME,
    service_url=SERVICE_URL,
)

接下来我们将创建我们的自查询检索器。为此，我们需要预先提供一些关于我们的文档支持的元数据字段的信息以及文档内容的简短描述。

from langchain.chains.query_constructor.base import AttributeInfo
from langchain.retrievers.self_query.base import SelfQueryRetriever
from langchain_openai import OpenAI

# Give LLM info about the metadata fields
metadata_field_info = [
    AttributeInfo(
        name="id",
        description="A UUID v1 generated from the date of the commit",
        type="uuid",
    ),
    AttributeInfo(
        name="date",
        description="The date of the commit in timestamptz format",
        type="timestamptz",
    ),
    AttributeInfo(
        name="author_name",
        description="The name of the author of the commit",
        type="string",
    ),
    AttributeInfo(
        name="author_email",
        description="The email address of the author of the commit",
        type="string",
    ),
]
document_content_description = "The git log commit summary containing the commit hash, author, date of commit, change summary and change details"

# Instantiate the self-query retriever from an LLM
llm = OpenAI(temperature=0)
retriever = SelfQueryRetriever.from_llm(
    llm,
    vectorstore,
    document_content_description,
    metadata_field_info,
    enable_limit=True,
    verbose=True,
)

API 参考：AttributeInfo | SelfQueryRetriever | OpenAI

现在让我们在我们的 gitlog 数据集上测试一下自查询检索器。

运行下面的查询，并注意您如何在自然语言中指定一个查询、带过滤器的查询和带复合过滤器的查询（带 AND、OR 的过滤器），自查询检索器将把该查询转换为 SQL 并执行对 Timescale Vector PostgreSQL 向量存储的搜索。

这说明了自查询检索器的强大功能。您可以使用它在您的向量存储上执行复杂的搜索，而您或您的用户无需直接编写任何 SQL 代码！

# This example specifies a relevant query
retriever.invoke("What are improvements made to continuous aggregates?")

/Users/avtharsewrathan/sideprojects2023/timescaleai/tsv-langchain/langchain/libs/langchain/langchain/chains/llm.py:275: UserWarning: The predict_and_parse method is deprecated, instead pass an output parser directly to LLMChain.
  warnings.warn(
``````output
query='improvements to continuous aggregates' filter=None limit=None

[Document(page_content='{"commit": " 35c91204987ccb0161d745af1a39b7eb91bc65a5", "author": "Fabr\\u00edzio de Royes Mello<[email protected]>", "date": "Thu Nov 24 13:19:36 2022 -0300", "change summary": "Add Hierarchical Continuous Aggregates validations", "change details": "Commit 3749953e introduce Hierarchical Continuous Aggregates (aka Continuous Aggregate on top of another Continuous Aggregate) but it lacks of some basic validations.  Validations added during the creation of a Hierarchical Continuous Aggregate:  * Forbid create a continuous aggregate with fixed-width bucket on top of   a continuous aggregate with variable-width bucket.  * Forbid incompatible bucket widths:   - should not be equal;   - bucket width of the new continuous aggregate should be greater than     the source continuous aggregate;   - bucket width of the new continuous aggregate should be multiple of     the source continuous aggregate. "}', metadata={'id': 'c98d1c00-6c13-11ed-9bbe-23925ce74d13', 'date': '2022-11-24 13:19:36+-500', 'source': '/Users/avtharsewrathan/sideprojects2023/timescaleai/tsv-langchain/langchain/docs/docs/modules/ts_git_log.json', 'seq_num': 446, 'author_name': 'Fabrízio de Royes Mello', 'commit_hash': ' 35c91204987ccb0161d745af1a39b7eb91bc65a5', 'author_email': '[email protected]'}),
 Document(page_content='{"commit": " 3749953e9704e45df8f621607989ada0714ce28d", "author": "Fabr\\u00edzio de Royes Mello<[email protected]>", "date": "Wed Oct 5 18:45:40 2022 -0300", "change summary": "Hierarchical Continuous Aggregates", "change details": "Enable users create Hierarchical Continuous Aggregates (aka Continuous Aggregates on top of another Continuous Aggregates).  With this PR users can create levels of aggregation granularity in Continuous Aggregates making the refresh process even faster.  A problem with this feature can be in upper levels we can end up with the \\"average of averages\\". But to get the \\"real average\\" we can rely on \\"stats_aggs\\" TimescaleDB Toolkit function that calculate and store the partials that can be finalized with other toolkit functions like \\"average\\" and \\"sum\\".  Closes #1400 "}', metadata={'id': '0df31a00-44f7-11ed-9794-ebcc1227340f', 'date': '2022-10-5 18:45:40+-500', 'source': '/Users/avtharsewrathan/sideprojects2023/timescaleai/tsv-langchain/langchain/docs/docs/modules/ts_git_log.json', 'seq_num': 470, 'author_name': 'Fabrízio de Royes Mello', 'commit_hash': ' 3749953e9704e45df8f621607989ada0714ce28d', 'author_email': '[email protected]'}),
 Document(page_content='{"commit": " a6ff7ba6cc15b280a275e5acd315741ec9c86acc", "author": "Mats Kindahl<[email protected]>", "date": "Tue Feb 28 12:04:17 2023 +0100", "change summary": "Rename columns in old-style continuous aggregates", "change details": "For continuous aggregates with the old-style partial aggregates renaming columns that are not in the group-by clause will generate an error when upgrading to a later version. The reason is that it is implicitly assumed that the name of the column is the same as for the direct view. This holds true for new-style continous aggregates, but is not always true for old-style continuous aggregates. In particular, columns that are not part of the `GROUP BY` clause can have an internally generated name.  This commit fixes that by extracting the name of the column from the partial view and use that when renaming the partial view column and the materialized table column. "}', metadata={'id': 'a49ace80-b757-11ed-8138-2390fd44ffd9', 'date': '2023-02-28 12:04:17+0140', 'source': '/Users/avtharsewrathan/sideprojects2023/timescaleai/tsv-langchain/langchain/docs/docs/modules/ts_git_log.json', 'seq_num': 294, 'author_name': 'Mats Kindahl', 'commit_hash': ' a6ff7ba6cc15b280a275e5acd315741ec9c86acc', 'author_email': '[email protected]'}),
 Document(page_content='{"commit": " 5bba74a2ec083728f8e93e09d03d102568fd72b5", "author": "Fabr\\u00edzio de Royes Mello<[email protected]>", "date": "Mon Aug 7 19:49:47 2023 -0300", "change summary": "Relax strong table lock when refreshing a CAGG", "change details": "When refreshing a Continuous Aggregate we take a table lock on _timescaledb_catalog.continuous_aggs_invalidation_threshold when processing the invalidation logs (the first transaction of the refresh Continuous Aggregate procedure). It means that even two different Continuous Aggregates over two different hypertables will wait each other in the first phase of the refreshing procedure. Also it lead to problems when a pg_dump is running because it take an AccessShareLock on tables so Continuous Aggregate refresh execution will wait until the pg_dump finish.  Improved it by relaxing the strong table-level lock to a row-level lock so now the Continuous Aggregate refresh procedure can be executed in multiple sessions with less locks.  Fix #3554 "}', metadata={'id': 'b5583780-3574-11ee-a5ba-2e305874a58f', 'date': '2023-08-7 19:49:47+-500', 'source': '/Users/avtharsewrathan/sideprojects2023/timescaleai/tsv-langchain/langchain/docs/docs/modules/ts_git_log.json', 'seq_num': 27, 'author_name': 'Fabrízio de Royes Mello', 'commit_hash': ' 5bba74a2ec083728f8e93e09d03d102568fd72b5', 'author_email': '[email protected]'})]

# This example specifies a filter
retriever.invoke("What commits did Sven Klemm add?")

query=' ' filter=Comparison(comparator=<Comparator.EQ: 'eq'>, attribute='author_name', value='Sven Klemm') limit=None

[Document(page_content='{"commit": " e2e7ae304521b74ac6b3f157a207da047d44ab06", "author": "Sven Klemm<[email protected]>", "date": "Fri Mar 3 11:22:06 2023 +0100", "change summary": "Don\'t run sanitizer test on individual PRs", "change details": "Sanitizer tests take a long time to run so we don\'t want to run them on individual PRs but instead run them nightly and on commits to master. "}', metadata={'id': '3f401b00-b9ad-11ed-b5ea-a3fd40b9ac16', 'date': '2023-03-3 11:22:06+0140', 'source': '/Users/avtharsewrathan/sideprojects2023/timescaleai/tsv-langchain/langchain/docs/docs/modules/ts_git_log.json', 'seq_num': 295, 'author_name': 'Sven Klemm', 'commit_hash': ' e2e7ae304521b74ac6b3f157a207da047d44ab06', 'author_email': '[email protected]'}),
 Document(page_content='{"commit": " d8f19e57a04d17593df5f2c694eae8775faddbc7", "author": "Sven Klemm<[email protected]>", "date": "Wed Feb 1 08:34:20 2023 +0100", "change summary": "Bump version of setup-wsl github action", "change details": "The currently used version pulls in Node.js 12 which is deprecated on github.  https://github.blog/changelog/2022-09-22-github-actions-all-actions-will-begin-running-on-node16-instead-of-node12/ "}', metadata={'id': 'd70de600-a202-11ed-85d6-30b6df240f49', 'date': '2023-02-1 08:34:20+0140', 'source': '/Users/avtharsewrathan/sideprojects2023/timescaleai/tsv-langchain/langchain/docs/docs/modules/ts_git_log.json', 'seq_num': 350, 'author_name': 'Sven Klemm', 'commit_hash': ' d8f19e57a04d17593df5f2c694eae8775faddbc7', 'author_email': '[email protected]'}),
 Document(page_content='{"commit": " 83b13cf6f73a74656dde9cc6ec6cf76740cddd3c", "author": "Sven Klemm<[email protected]>", "date": "Fri Nov 25 08:27:45 2022 +0100", "change summary": "Use packaged postgres for sqlsmith and coverity CI", "change details": "The sqlsmith and coverity workflows used the cache postgres build but could not produce a build by themselves and therefore relied on other workflows to produce the cached binaries. This patch changes those workflows to use normal postgres packages instead of custom built postgres to remove that dependency. "}', metadata={'id': 'a786ae80-6c92-11ed-bd6c-a57bd3348b97', 'date': '2022-11-25 08:27:45+0140', 'source': '/Users/avtharsewrathan/sideprojects2023/timescaleai/tsv-langchain/langchain/docs/docs/modules/ts_git_log.json', 'seq_num': 447, 'author_name': 'Sven Klemm', 'commit_hash': ' 83b13cf6f73a74656dde9cc6ec6cf76740cddd3c', 'author_email': '[email protected]'}),
 Document(page_content='{"commit": " b1314e63f2ff6151ab5becfb105afa3682286a4d", "author": "Sven Klemm<[email protected]>", "date": "Thu Dec 22 12:03:35 2022 +0100", "change summary": "Fix RPM package test for PG15 on centos 7", "change details": "Installing PG15 on Centos 7 requires the EPEL repository to satisfy the dependencies. "}', metadata={'id': '477b1d80-81e8-11ed-9c8c-9b5abbd67c98', 'date': '2022-12-22 12:03:35+0140', 'source': '/Users/avtharsewrathan/sideprojects2023/timescaleai/tsv-langchain/langchain/docs/docs/modules/ts_git_log.json', 'seq_num': 408, 'author_name': 'Sven Klemm', 'commit_hash': ' b1314e63f2ff6151ab5becfb105afa3682286a4d', 'author_email': '[email protected]'})]

# This example specifies a query and filter
retriever.invoke("What commits about timescaledb_functions did Sven Klemm add?")

query='timescaledb_functions' filter=Comparison(comparator=<Comparator.EQ: 'eq'>, attribute='author_name', value='Sven Klemm') limit=None

[Document(page_content='{"commit": " 04f43335dea11e9c467ee558ad8edfc00c1a45ed", "author": "Sven Klemm<[email protected]>", "date": "Thu Apr 6 13:00:00 2023 +0200", "change summary": "Move aggregate support function into _timescaledb_functions", "change details": "This patch moves the support functions for histogram, first and last into the _timescaledb_functions schema. Since we alter the schema of the existing functions in upgrade scripts and do not change the aggregates this should work completely transparently for any user objects using those aggregates. "}', metadata={'id': '2cb47800-d46a-11ed-8f0e-2b624245c561', 'date': '2023-04-6 13:00:00+0320', 'source': '/Users/avtharsewrathan/sideprojects2023/timescaleai/tsv-langchain/langchain/docs/docs/modules/ts_git_log.json', 'seq_num': 233, 'author_name': 'Sven Klemm', 'commit_hash': ' 04f43335dea11e9c467ee558ad8edfc00c1a45ed', 'author_email': '[email protected]'}),
 Document(page_content='{"commit": " feef9206facc5c5f506661de4a81d96ef059b095", "author": "Sven Klemm<[email protected]>", "date": "Fri Mar 31 08:22:57 2023 +0200", "change summary": "Add _timescaledb_functions schema", "change details": "Currently internal user objects like chunks and our functions live in the same schema making locking down that schema hard. This patch adds a new schema _timescaledb_functions that is meant to be the schema used for timescaledb internal functions to allow separation of code and chunks or other user objects. "}', metadata={'id': '7a257680-cf8c-11ed-848c-a515e8687479', 'date': '2023-03-31 08:22:57+0320', 'source': '/Users/avtharsewrathan/sideprojects2023/timescaleai/tsv-langchain/langchain/docs/docs/modules/ts_git_log.json', 'seq_num': 239, 'author_name': 'Sven Klemm', 'commit_hash': ' feef9206facc5c5f506661de4a81d96ef059b095', 'author_email': '[email protected]'}),
 Document(page_content='{"commit": " 0a66bdb8d36a1879246bd652e4c28500c4b951ab", "author": "Sven Klemm<[email protected]>", "date": "Sun Aug 20 22:47:10 2023 +0200", "change summary": "Move functions to _timescaledb_functions schema", "change details": "To increase schema security we do not want to mix our own internal objects with user objects. Since chunks are created in the _timescaledb_internal schema our internal functions should live in a different dedicated schema. This patch make the necessary adjustments for the following functions:  - to_unix_microseconds(timestamptz) - to_timestamp(bigint) - to_timestamp_without_timezone(bigint) - to_date(bigint) - to_interval(bigint) - interval_to_usec(interval) - time_to_internal(anyelement) - subtract_integer_from_now(regclass, bigint) "}', metadata={'id': 'bb99db00-3f9a-11ee-a8dc-0b9c1a5a37c4', 'date': '2023-08-20 22:47:10+0320', 'source': '/Users/avtharsewrathan/sideprojects2023/timescaleai/tsv-langchain/langchain/docs/docs/modules/ts_git_log.json', 'seq_num': 41, 'author_name': 'Sven Klemm', 'commit_hash': ' 0a66bdb8d36a1879246bd652e4c28500c4b951ab', 'author_email': '[email protected]'}),
 Document(page_content='{"commit": " 56ea8b4de93cefc38e002202d8ac96947dcbaa77", "author": "Sven Klemm<[email protected]>", "date": "Thu Apr 13 13:16:14 2023 +0200", "change summary": "Move trigger functions to _timescaledb_functions schema", "change details": "To increase schema security we do not want to mix our own internal objects with user objects. Since chunks are created in the _timescaledb_internal schema our internal functions should live in a different dedicated schema. This patch make the necessary adjustments for our trigger functions. "}', metadata={'id': '9a255300-d9ec-11ed-988f-7086c8ca463a', 'date': '2023-04-13 13:16:14+0320', 'source': '/Users/avtharsewrathan/sideprojects2023/timescaleai/tsv-langchain/langchain/docs/docs/modules/ts_git_log.json', 'seq_num': 44, 'author_name': 'Sven Klemm', 'commit_hash': ' 56ea8b4de93cefc38e002202d8ac96947dcbaa77', 'author_email': '[email protected]'})]

# This example specifies a time-based filter
retriever.invoke("What commits were added in July 2023?")

query=' ' filter=Operation(operator=<Operator.AND: 'and'>, arguments=[Comparison(comparator=<Comparator.GTE: 'gte'>, attribute='date', value='2023-07-01T00:00:00Z'), Comparison(comparator=<Comparator.LTE: 'lte'>, attribute='date', value='2023-07-31T23:59:59Z')]) limit=None

[Document(page_content='{"commit": " 5cf354e2469ee7e43248bed382a4b49fc7ccfecd", "author": "Markus Engel<[email protected]>", "date": "Mon Jul 31 11:28:25 2023 +0200", "change summary": "Fix quoting owners in sql scripts.", "change details": "When referring to a role from a string type, it must be properly quoted using pg_catalog.quote_ident before it can be casted to regrole. Fixed this, especially in update scripts. "}', metadata={'id': '99590280-2f84-11ee-915b-5715b2447de4', 'date': '2023-07-31 11:28:25+0320', 'source': '/Users/avtharsewrathan/sideprojects2023/timescaleai/tsv-langchain/langchain/docs/docs/modules/ts_git_log.json', 'seq_num': 76, 'author_name': 'Markus Engel', 'commit_hash': ' 5cf354e2469ee7e43248bed382a4b49fc7ccfecd', 'author_email': '[email protected]'}),
 Document(page_content='{"commit": " 88aaf23ae37fe7f47252b87325eb570aa417c607", "author": "noctarius aka Christoph Engelbert<[email protected]>", "date": "Wed Jul 12 14:53:40 2023 +0200", "change summary": "Allow Replica Identity (Alter Table) on CAGGs (#5868)", "change details": "This commit is a follow up of #5515, which added support for ALTER TABLE\\r ... REPLICA IDENTITY (FULL | INDEX) on hypertables.\\r \\r This commit allows the execution against materialized hypertables to\\r enable update / delete operations on continuous aggregates when logical\\r replication in enabled for them."}', metadata={'id': '1fcfa200-20b3-11ee-9a18-370561c7cb1a', 'date': '2023-07-12 14:53:40+0320', 'source': '/Users/avtharsewrathan/sideprojects2023/timescaleai/tsv-langchain/langchain/docs/docs/modules/ts_git_log.json', 'seq_num': 96, 'author_name': 'noctarius aka Christoph Engelbert', 'commit_hash': ' 88aaf23ae37fe7f47252b87325eb570aa417c607', 'author_email': '[email protected]'}),
 Document(page_content='{"commit": " d5268c36fbd23fa2a93c0371998286e8688247bb", "author": "Alexander Kuzmenkov<[email protected]>", "date": "Fri Jul 28 13:35:05 2023 +0200", "change summary": "Fix SQLSmith workflow", "change details": "The build was failing because it was picking up the wrong version of Postgres. Remove it. "}', metadata={'id': 'cc0fba80-2d3a-11ee-ae7d-36dc25cad3b8', 'date': '2023-07-28 13:35:05+0320', 'source': '/Users/avtharsewrathan/sideprojects2023/timescaleai/tsv-langchain/langchain/docs/docs/modules/ts_git_log.json', 'seq_num': 82, 'author_name': 'Alexander Kuzmenkov', 'commit_hash': ' d5268c36fbd23fa2a93c0371998286e8688247bb', 'author_email': '[email protected]'}),
 Document(page_content='{"commit": " 61c288ec5eb966a9b4d8ed90cd026ffc5e3543c9", "author": "Lakshmi Narayanan Sreethar<[email protected]>", "date": "Tue Jul 25 16:11:35 2023 +0530", "change summary": "Fix broken CI after PG12 removal", "change details": "The commit cdea343cc updated the gh_matrix_builder.py script but failed to import PG_LATEST variable into the script thus breaking the CI. Import that variable to fix the CI tests. "}', metadata={'id': 'd3835980-2ad7-11ee-b98d-c4e3092e076e', 'date': '2023-07-25 16:11:35+0850', 'source': '/Users/avtharsewrathan/sideprojects2023/timescaleai/tsv-langchain/langchain/docs/docs/modules/ts_git_log.json', 'seq_num': 84, 'author_name': 'Lakshmi Narayanan Sreethar', 'commit_hash': ' 61c288ec5eb966a9b4d8ed90cd026ffc5e3543c9', 'author_email': '[email protected]'})]

# This example specifies a query and a LIMIT value
retriever.invoke("What are two commits about hierarchical continuous aggregates?")

query='hierarchical continuous aggregates' filter=None limit=2

[Document(page_content='{"commit": " 35c91204987ccb0161d745af1a39b7eb91bc65a5", "author": "Fabr\\u00edzio de Royes Mello<[email protected]>", "date": "Thu Nov 24 13:19:36 2022 -0300", "change summary": "Add Hierarchical Continuous Aggregates validations", "change details": "Commit 3749953e introduce Hierarchical Continuous Aggregates (aka Continuous Aggregate on top of another Continuous Aggregate) but it lacks of some basic validations.  Validations added during the creation of a Hierarchical Continuous Aggregate:  * Forbid create a continuous aggregate with fixed-width bucket on top of   a continuous aggregate with variable-width bucket.  * Forbid incompatible bucket widths:   - should not be equal;   - bucket width of the new continuous aggregate should be greater than     the source continuous aggregate;   - bucket width of the new continuous aggregate should be multiple of     the source continuous aggregate. "}', metadata={'id': 'c98d1c00-6c13-11ed-9bbe-23925ce74d13', 'date': '2022-11-24 13:19:36+-500', 'source': '/Users/avtharsewrathan/sideprojects2023/timescaleai/tsv-langchain/langchain/docs/docs/modules/ts_git_log.json', 'seq_num': 446, 'author_name': 'Fabrízio de Royes Mello', 'commit_hash': ' 35c91204987ccb0161d745af1a39b7eb91bc65a5', 'author_email': '[email protected]'}),
 Document(page_content='{"commit": " 3749953e9704e45df8f621607989ada0714ce28d", "author": "Fabr\\u00edzio de Royes Mello<[email protected]>", "date": "Wed Oct 5 18:45:40 2022 -0300", "change summary": "Hierarchical Continuous Aggregates", "change details": "Enable users create Hierarchical Continuous Aggregates (aka Continuous Aggregates on top of another Continuous Aggregates).  With this PR users can create levels of aggregation granularity in Continuous Aggregates making the refresh process even faster.  A problem with this feature can be in upper levels we can end up with the \\"average of averages\\". But to get the \\"real average\\" we can rely on \\"stats_aggs\\" TimescaleDB Toolkit function that calculate and store the partials that can be finalized with other toolkit functions like \\"average\\" and \\"sum\\".  Closes #1400 "}', metadata={'id': '0df31a00-44f7-11ed-9794-ebcc1227340f', 'date': '2022-10-5 18:45:40+-500', 'source': '/Users/avtharsewrathan/sideprojects2023/timescaleai/tsv-langchain/langchain/docs/docs/modules/ts_git_log.json', 'seq_num': 470, 'author_name': 'Fabrízio de Royes Mello', 'commit_hash': ' 3749953e9704e45df8f621607989ada0714ce28d', 'author_email': '[email protected]'})]

5. 使用现有的 TimescaleVector 向量存储

在上面的示例中，我们从文档集合中创建了向量存储。但是，通常我们希望将数据插入现有的向量存储并从中查询数据。让我们看看如何初始化、将文档添加到 TimescaleVector 向量存储中的现有文档集合以及查询这些文档。

要使用现有的 Timescale Vector 存储，我们需要知道要查询的表的名称 (COLLECTION_NAME) 以及云 PostgreSQL 数据库的 URL (SERVICE_URL)。

# Initialize the existing
COLLECTION_NAME = "timescale_commits"
embeddings = OpenAIEmbeddings()
vectorstore = TimescaleVector(
    collection_name=COLLECTION_NAME,
    service_url=SERVICE_URL,
    embedding_function=embeddings,
)

要将新数据加载到表中，我们使用 add_document() 函数。此函数接受一个文档列表和一个元数据列表。元数据必须包含每个文档的唯一 id。

如果您希望将您的文档与当前日期和时间相关联，您不需要创建 id 列表。每个文档都会自动生成一个 uuid。

如果您希望将您的文档与过去的时间相关联，您可以使用 timecale-vector python 库中的 uuid_from_time 函数创建 id 列表，如上面的第 2 节所示。此函数接受一个 datetime 对象并返回一个 uuid，其中编码了日期和时间。

# Add documents to a collection in TimescaleVector
ids = vectorstore.add_documents([Document(page_content="foo")])
ids

['a34f2b8a-53d7-11ee-8cc3-de1e4b2a0118']

# Query the vectorstore for similar documents
docs_with_score = vectorstore.similarity_search_with_score("foo")

docs_with_score[0]

(Document(page_content='foo', metadata={}), 5.006789860928507e-06)

docs_with_score[1]

(Document(page_content='{"commit": " 00b566dfe478c11134bcf1e7bcf38943e7fafe8f", "author": "Fabr\\u00edzio de Royes Mello<[email protected]>", "date": "Mon Mar 6 15:51:03 2023 -0300", "change summary": "Remove unused functions", "change details": "We don\'t use `ts_catalog_delete[_only]` functions anywhere and instead we rely on `ts_catalog_delete_tid[_only]` functions so removing it from our code base. "}', metadata={'id': 'd7f5c580-bc4f-11ed-9712-ffa0126a201a', 'date': '2023-03-6 15:51:03+-500', 'source': '/Users/avtharsewrathan/sideprojects2023/timescaleai/tsv-langchain/langchain/docs/docs/modules/ts_git_log.json', 'seq_num': 285, 'author_name': 'Fabrízio de Royes Mello', 'commit_hash': ' 00b566dfe478c11134bcf1e7bcf38943e7fafe8f', 'author_email': '[email protected]'}),
 0.23607668446580354)

删除数据

您可以通过 uuid 或通过元数据的过滤器删除数据。

ids = vectorstore.add_documents([Document(page_content="Bar")])

vectorstore.delete(ids)

True

使用元数据进行删除在您想要定期更新从特定来源或特定日期或其他元数据属性中抓取的信息时特别有用。

vectorstore.add_documents(
    [Document(page_content="Hello World", metadata={"source": "www.example.com/hello"})]
)
vectorstore.add_documents(
    [Document(page_content="Adios", metadata={"source": "www.example.com/adios"})]
)

vectorstore.delete_by_metadata({"source": "www.example.com/adios"})

vectorstore.add_documents(
    [
        Document(
            page_content="Adios, but newer!",
            metadata={"source": "www.example.com/adios"},
        )
    ]
)

['c6367004-53d7-11ee-8cc3-de1e4b2a0118']

覆盖向量存储

如果您有一个现有的集合，您可以通过执行 from_documents 并设置 pre_delete_collection = True 来覆盖它。

db = TimescaleVector.from_documents(
    documents=docs,
    embedding=embeddings,
    collection_name=COLLECTION_NAME,
    service_url=SERVICE_URL,
    pre_delete_collection=True,
)

docs_with_score = db.similarity_search_with_score("foo")

docs_with_score[0]

向量存储概念指南
向量存储操作指南

Timescale Vector (PostgreSQL)

什么是 Timescale Vector？

如何访问 Timescale Vector

设置

1. 使用欧几里得距离（默认）进行相似性搜索

使用 Timescale Vector 作为检索器

2. 使用基于时间的过滤进行相似性搜索

从 git 日志 JSON 中提取内容和元数据

将文档和元数据加载到 TimescaleVector 向量存储中

按时间和相似度查询向量

3. 使用 ANN 搜索索引来加速查询

4. 使用 Timescale Vector 的自查询检索器

5. 使用现有的 TimescaleVector 向量存储

删除数据

覆盖向量存储

此页面是否有帮助？

您也可以在 GitHub 上留下详细的反馈在 GitHub 上.

Timescale Vector (PostgreSQL)

什么是 Timescale Vector？​

如何访问 Timescale Vector​

设置​

1. 使用欧几里得距离（默认）进行相似性搜索​

使用 Timescale Vector 作为检索器​

2. 使用基于时间的过滤进行相似性搜索​

从 git 日志 JSON 中提取内容和元数据​

将文档和元数据加载到 TimescaleVector 向量存储中​

按时间和相似度查询向量​

3. 使用 ANN 搜索索引来加速查询​

4. 使用 Timescale Vector 的自查询检索器​

5. 使用现有的 TimescaleVector 向量存储​

删除数据​

覆盖向量存储​

相关​

此页面是否有帮助？

您也可以在 GitHub 上留下详细的反馈 在 GitHub 上.

什么是 Timescale Vector？

如何访问 Timescale Vector

设置

1. 使用欧几里得距离（默认）进行相似性搜索

使用 Timescale Vector 作为检索器

2. 使用基于时间的过滤进行相似性搜索

从 git 日志 JSON 中提取内容和元数据

将文档和元数据加载到 TimescaleVector 向量存储中

按时间和相似度查询向量

3. 使用 ANN 搜索索引来加速查询

4. 使用 Timescale Vector 的自查询检索器

5. 使用现有的 TimescaleVector 向量存储

删除数据

覆盖向量存储

相关

您也可以在 GitHub 上留下详细的反馈在 GitHub 上.