文章作者:
石强,镜舟科技解决方案架构师
赵恒,StarRocks TSC Member
RAG 和向量索引简介RAG(Retrieval-Augmented Generation,检索增强生成)是一种结合外部知识检索与 AI 生成的技术,弥补了传统大模型知识静态、易编造信息的缺陷,使回答更加准确且基于实时信息。
RAG 的核心流程检索(Retrieval)用户输入问题后,RAG 从外部数据库(如维基百科、企业文档、科研论文等)检索相关内容。检索工具可以是向量数据库、搜索引擎或传统数据库。生成(Generation)将检索到的相关信息与用户输入一起输入生成模型(如 GPT、LLaMA 等),生成更准确的回答。模型基于检索内容“增强”输出,而非仅依赖内部参数化知识。上图展示了 RAG 的标准流程。首先,图片、文档、视频和音频等数据经过预处理,转换为 Embedding 并存入向量数据库。Embedding 通常是高维 float 数组,借助向量索引(如 HNSW、IVF)进行相似性搜索,加速高效检索。
向量索引通过近似最近邻(ANN)算法优化查询效率,减少高维计算负担。语义搜索匹配用户问题与知识库中的相关内容,使回答基于真实信息,从而降低大模型的“幻觉”风险,提升回答的自然性和可靠性。
StarRocks + DeepSeek 的典型 RAG 应用场景DeepSeek 负责生成高质量 Embedding 和回答,StarRocks 提供实时高效的向量检索,二者结合可构建更智能、更精准的 AI 解决方案。
企业级知识库适用场景:企业内部知识库(文档搜索、FAQ)法律、金融、医药等专业领域问答代码搜索、软件开发文档查询方案:文档嵌入(DeepSeek 负责): 将企业知识库、FAQ、技术文档等数据转换为向量。存储+索引(StarRocks 负责): 使用 HNSW 或 IVFPQ 存储向量存储在 StarRocks 中,支持高效检索。检索增强生成(RAG 负责): 用户输入问题 → DeepSeek 生成查询向量 → StarRocks 进行向量匹配 → 返回相关文档 → DeepSeek 结合文档生成最终回答。AI 客服与智能问答适用场景:智能客服(银行、证券、电商)法律、医疗等专业咨询技术支持自动问答方案:客户对话日志嵌入(DeepSeek 负责): 训练 LLM 处理用户意图,转换历史聊天记录为向量。存储+索引(StarRocks 负责): 采用向量索引让客服系统能够高效查找相似案例。检索增强(RAG 负责): 结合历史客服对话 + 知识库 + DeepSeek LLM 生成答案。示例流程:用户问:“我如何更改银行卡预留手机号?”StarRocks 检索到 3 个最相似的客户服务记录DeepSeek 结合这 3 条历史记录 + 预设 FAQ,生成精准回答操作演示系统组成DeepSeek:提供文本向量化(embedding)和答案生成能力StarRocks:高效存储和检索向量数据(3.4+版本支持向量索引)实现流程:步骤
负责组件
具体实现
环境准备
Ollama StarRocks
用 Ollama 在本地机器上便捷地部署和运行大型语言模型
数据向量化
DeepSeek-Embedding
文本 → 3584 维向量
存储向量
StarRocks
创建表,存入向量
近似最近邻搜索
StarRocks 向量索引
IVFPQ / HNSW 检索
检索增强
模拟 RAG 逻辑
结合检索数据
生成答案
DeepSeek LLM
生成基于真实数据的回答
1.环境准备1.1 DeepSeek 本地部署Tips: 以下内容使用的是 macbook 进行 demo 演示
1.1.1 使用 ollama 安装本地模型在本地部署 DeepSeek 时,Ollama 主要起到模型管理和提供推理接口的作用,支持运行多个不同的 LLM,并允许用户在本地切换和管理不同的模型。
下载 ollama:https://ollama.com/安装 deepseek-r1:7b代码语言:javascript代码运行次数:0运行复制# 该命令会自动下载并加载模型ollama run deepseek-r1:7b
1.1.2 Deepseek 初步使用
启动 deepseek
代码语言:javascript代码运行次数:0运行复制执行 ollama run deepseek-r1:7b 直接进入交互模式
直接在命令行设置参数:(参数单次生效)
代码语言:javascript代码运行次数:0运行复制OLLAMA_GPU_LAYERS=35 \OLLAMA_CPU_THREADS=6 \OLLAMA_BATCH_SIZE=128 \OLLAMA_CONTEXT_SIZE=4096 \ollama run deepseek-r1:7b
显而易见:直接使用 deepseek 进行问答,返回的答案是不符合预期的,需要对知识进行修正
1.2 StarRocks 准备工作1.2.1 集群部署版本需求:3.4 及以上
1.2.2 配置设置打开 vector index
代码语言:javascript代码运行次数:0运行复制ADMIN SET FRONTEND CONFIG ("enable_experimental_vector" = "true");
建库:
代码语言:javascript代码运行次数:0运行复制create database knowledge_base;
建表:存储知识库向量
代码语言:javascript代码运行次数:0运行复制CREATE TABLE enterprise_knowledge ( id BIGINT AUTO_INCREMENT, content TEXT NOT NULL, embedding ARRAY<FLOAT> NOT NULL, INDEX vec_idx (embedding) USING VECTOR ( "index_type" = "hnsw", "dim" = "3584", "metric_type" = "l2_distance", "M" = "16", "efconstruction" = "40" )) ENGINE=OLAPPRIMARY KEY(id)DISTRIBUTED BY HASH(id) BUCKETS 1PROPERTIES ( "replication_num" = "1" );
Tips: DeepSeek 的 deepseek-r1:7b 模型(7B 参数版本)默认生成高维嵌入向量,通常是 3584 维
2.将文本转成向量测试通过 deepseek 将文本转为 3584 维向量
代码语言:javascript代码运行次数:0运行复制curl -X POST http://localhost:11434/api/embeddings -d '{"model": "deepseek-r1:7b", "prompt": "产品保修期是一年。"}'
下面将转化的向量数据保存在 StarRocks 中
3.知识存储 (存储向量到 StarRocks)代码语言:javascript代码运行次数:0运行复制import pymysqlimport requestsdef get_embedding(text): url = "http://localhost:11434/api/embeddings" payload = {"model": "deepseek-r1:7b", "prompt": text} response = requests.post(url, json=payload) response.raise_for_status() return response.json()["embedding"]try: content = "StarRocks 的愿景是能够让用户的数据分析变得更加简单和敏捷。" embedding = get_embedding(content) # 将 Python 列表转换为 StarRocks 的数组格式 embedding_str = "[" + ",".join(map(str, embedding)) + "]" # 例如:[0.1,0.2,0.3] conn = pymysql.connect( host='X.X.X.X', port=9030, user='root', password='sr123456', database='knowledge_base' ) cursor = conn.cursor() # 使用格式化的数组字符串 sql = "INSERT INTO enterprise_knowledge (content, embedding) VALUES (%s, %s)" cursor.execute(sql, (content, embedding_str)) conn.commit() print(f"Inserted: {content} with embedding {embedding[:5]}...")except requests.RequestException as e: print(f"Embedding API error: {e}")except pymysql.Error as db_err: print(f"Database error: {db_err}")finally: if 'cursor' in locals(): cursor.close() if 'conn' in locals(): conn.close()
import pymysqlimport requests# 获取嵌入向量的函数def get_embedding(text): url = "http://localhost:11434/api/embeddings" payload = {"model": "deepseek-r1:7b", "prompt": text} response = requests.post(url, json=payload) response.raise_for_status() return response.json()["embedding"]# 从 StarRocks 查询相似内容的函数def search_knowledge_base(query_embedding): try: conn = pymysql.connect( host='39.98.110.249', port=9030, user='root', password='sr123456', database='knowledge_base' ) cursor = conn.cursor() # 将查询向量转换为 StarRocks 的数组格式 embedding_str = "[" + ",".join(map(str, query_embedding)) + "]" # 使用 L2 距离搜索最相似的记录 sql = """ SELECT content, l2_distance(embedding, %s) AS distance FROM enterprise_knowledge ORDER BY distance ASC LIMIT 1 """ cursor.execute(sql, (embedding_str,)) result = cursor.fetchone() if result: return result[0] # 返回最匹配的 content else: return "未找到相关信息。" except pymysql.Error as db_err: print(f"Database error: {db_err}") return "查询失败。" finally: if 'cursor' in locals(): cursor.close() if 'conn' in locals(): conn.close()# 主流程try: query = "StarRocks 的愿景是什么?" query_embedding = get_embedding(query) # 将查询转化为向量 answer = search_knowledge_base(query_embedding) # 从知识库检索答案 print(f"问题: {query}") print(f"回答: {answer}")except requests.RequestException as e: print(f"Embedding API error: {e}")except Exception as e: print(f"Error: {e}")
执行效果
补充说明:到目前为止的流程仅依赖 StarRocks 进行向量检索,未利用 DeepSeek LLM 进行生成,导致回答生硬且缺乏上下文整合,影响自然性和准确性。为提升效果,应引入 RAG 机制,使检索结果与生成模型深度融合,从而优化回答质量并减少幻觉问题。
5.加入 RAG 增强5.1 将查询知识库的结果,返回给 DeepSeek LLM ,优化回答质量代码语言:javascript代码运行次数:0运行复制# 构造 RAG Promptdef build_rag_prompt(query, retrieved_content): prompt = f""" [系统指令] 你是企业智能客服,基于以下知识回答用户问题: [知识上下文] {retrieved_content} [用户问题] {query} """ return prompt# 调用 DeepSeek 生成回答def generate_answer(prompt): url = "http://localhost:11434/api/generate" payload = {"model": "deepseek-r1:7b", "prompt": prompt} try: response = requests.post(url, json=payload) response.raise_for_status() full_response = "" for line in response.text.splitlines(): if line.strip(): # 过滤空行 try: json_obj = json.loads(line) if "response" in json_obj: full_response += json_obj["response"] # 只提取答案 if json_obj.get("done", False): break except json.JSONDecodeError as e: print(f"JSON 解析错误: {e}, line: {line}") return clean_response(full_response.strip()) # 处理并去掉 <think>XXX</think> except requests.exceptions.RequestException as e: print(f"请求失败: {e}") return "生成失败。"
用于记录用户问题、检索结果和生成回答,保存上下文,方便进行长对话,至于长对话,用户可自行探索。
customer_service_log 表建表语句如下:
代码语言:javascript代码运行次数:0运行复制CREATE TABLE customer_service_log ( id BIGINT AUTO_INCREMENT, user_id VARCHAR(50), question TEXT NOT NULL, question_embedding ARRAY<FLOAT> NOT NULL, retrieved_content TEXT, generated_answer TEXT, timestamp DATETIME NOT NULL, feedback TINYINT DEFAULT NULL) ENGINE=OLAPPRIMARY KEY(id)DISTRIBUTED BY HASH(id) BUCKETS 1PROPERTIES ( "replication_num" = "1");
import pymysqlimport requestsimport jsonfrom datetime import datetimeimport loggingimport re# 获取嵌入向量def get_embedding(text): url = "http://localhost:11434/api/embeddings" payload = {"model": "deepseek-r1:7b", "prompt": text,"stream": "true"} response = requests.post(url, json=payload) response.raise_for_status() return response.json()["embedding"]# 从 StarRocks 检索知识def search_knowledge_base(query_embedding): try: conn = pymysql.connect( host='X.X.X.X', port=9030, user='root', password='sr123456', database='knowledge_base' ) cursor = conn.cursor() embedding_str = "[" + ",".join(map(str, query_embedding)) + "]" sql = """ SELECT content, l2_distance(embedding, %s) AS distance FROM enterprise_knowledge ORDER BY distance ASC LIMIT 3 """ cursor.execute(sql, (embedding_str,)) results=cursor.fetchall() content="" for result in results: content+=result[0] return content except pymysql.Error as db_err: print(f"Database error: {db_err}") return "查询失败。" finally: cursor.close() conn.close()def build_rag_prompt(query, retrieved_content): prompt = f""" [系统指令] 你是企业智能客服,基于以下知识回答用户问题: [知识上下文] {retrieved_content} [用户问题] {query} """ return prompt# 调用 DeepSeek 生成回答def generate_answer(prompt): url = "http://localhost:11434/api/generate" payload = {"model": "deepseek-r1:7b", "prompt": prompt} try: response = requests.post(url, json=payload) response.raise_for_status() full_response = "" for line in response.text.splitlines(): if line.strip(): # 过滤空行 try: json_obj = json.loads(line) if "response" in json_obj: full_response += json_obj["response"] # 只提取答案 if json_obj.get("done", False): break except json.JSONDecodeError as e: print(f"JSON 解析错误: {e}, line: {line}") return clean_response(full_response.strip()) # 处理并去掉 <think>XXX</think> except requests.exceptions.RequestException as e: print(f"请求失败: {e}") return "生成失败。"# 记录对话日志def log_conversation(user_id, question, question_embedding, retrieved_content, generated_answer): try: conn = pymysql.connect( host='X.X.X.X', port=9030, user='root', password='sr123456', database='knowledge_base' ) cursor = conn.cursor() embedding_str = "[" + ",".join(map(str, question_embedding)) + "]" sql = """ INSERT INTO customer_service_log (user_id, question, question_embedding, retrieved_content, generated_answer, timestamp) VALUES (%s, %s, %s, %s, %s, NOW()) """ cursor.execute(sql, (user_id, question, embedding_str, retrieved_content, generated_answer)) conn.commit() except pymysql.Error as db_err: print(f"Database error: {db_err}") finally: cursor.close() conn.close()def clean_response(text): # 去掉所有 <think>xxx</think> 结构 return re.sub(r"<think>.*?</think>", "", text, flags=re.DOTALL).strip()# 主流程def rag_pipeline(user_id, query): try: logging.info(f"开始处理查询: {query}") query_embedding = get_embedding(query) logging.info("获取嵌入向量成功") retrieved_content = search_knowledge_base(query_embedding) logging.info(f"检索到内容: {retrieved_content[:50]}...") # 只展示前50字符 prompt = build_rag_prompt(query, retrieved_content) generated_answer = generate_answer(prompt) logging.info(f"生成回答: {generated_answer[:50]}...") log_conversation(user_id, query, query_embedding, retrieved_content, generated_answer) logging.info("日志记录完成") return generated_answer except Exception as e: logging.error(f"发生错误: {e}", exc_info=True) return "处理失败。"# 测试if __name__ == '__main__': logging.basicConfig(level=logging.INFO, format="%(asctime)s - %(levelname)s - %(message)s") user_id = "user123" query = "StarRocks 的愿景是什么?" answer = rag_pipeline(user_id, query) print(f"问题: {query}") print(f"回答: {answer}")
<!DOCTYPE html><html lang="zh"><head> <meta charset="UTF-8"> <meta name="viewport" content="width=device-width, initial-scale=1.0"> <title>智能问答客服系统</title> <script> async function askQuestion() { let question = document.getElementById("question").value; let response = await fetch("/ask", { method: "POST", headers: { "Content-Type": "application/json" }, body: JSON.stringify({ question: question }) }); let data = await response.json(); document.getElementById("answer").innerText = data.answer; } </script></head><body> <h1>智能问答客服系统</h1> <input type="text" id="question" placeholder="请输入您的问题"> <button onclick="askQuestion()">提问</button> <p id="answer"></p></body></html>
import pymysqlimport requestsdef get_embedding(text): url = "http://localhost:11434/api/embeddings" payload = {"model": "deepseek-r1:7b", "prompt": text} response = requests.post(url, json=payload) response.raise_for_status() return response.json()["embedding"]try: content = "StarRocks 的愿景是能够让用户的数据分析变得更加简单和敏捷。" embedding = get_embedding(content) # 将 Python 列表转换为 StarRocks 的数组格式 embedding_str = "[" + ",".join(map(str, embedding)) + "]" # 例如:[0.1,0.2,0.3] conn = pymysql.connect( host='X.X.X.X', port=9030, user='root', password='sr123456', database='knowledge_base' ) cursor = conn.cursor() # 使用格式化的数组字符串 sql = "INSERT INTO enterprise_knowledge (content, embedding) VALUES (%s, %s)" cursor.execute(sql, (content, embedding_str)) conn.commit() print(f"Inserted: {content} with embedding {embedding[:5]}...")except requests.RequestException as e: print(f"Embedding API error: {e}")except pymysql.Error as db_err: print(f"Database error: {db_err}")finally: if 'cursor' in locals(): cursor.close() if 'conn' in locals(): conn.close()
import pymysqlimport requestsimport jsonimport loggingimport refrom flask import Flask, request, jsonify, render_templateapp = Flask(__name__)# 配置日志logging.basicConfig(level=logging.INFO, format="%(asctime)s - %(levelname)s - %(message)s")# 获取嵌入向量def get_embedding(text): url = "http://localhost:11434/api/embeddings" payload = {"model": "deepseek-r1:7b", "prompt": text, "stream": "true"} response = requests.post(url, json=payload) response.raise_for_status() return response.json()["embedding"]# 从 StarRocks 检索知识def search_knowledge_base(query_embedding): try: conn = pymysql.connect( host='X.X.X.X', port=9030, user='root', password='sr123456', database='knowledge_base' ) cursor = conn.cursor() embedding_str = "[" + ",".join(map(str, query_embedding)) + "]" sql = """ SELECT content, l2_distance(embedding, %s) AS distance FROM enterprise_knowledge ORDER BY distance ASC LIMIT 3 """ cursor.execute(sql, (embedding_str,)) results=cursor.fetchall() content="" for result in results: content+=result[0] # result = cursor.fetchone() return content except pymysql.Error as db_err: print(f"Database error: {db_err}") return "查询失败。" finally: cursor.close() conn.close()# 构造 RAG Promptdef build_rag_prompt(query, retrieved_content): return f""" [系统指令] 你是企业智能客服,基于以下知识回答用户问题: [知识上下文] {retrieved_content} [用户问题] {query} """# 调用 DeepSeek 生成回答def generate_answer(prompt): url = "http://localhost:11434/api/generate" payload = {"model": "deepseek-r1:7b", "prompt": prompt} try: response = requests.post(url, json=payload) response.raise_for_status() full_response = "" for line in response.text.splitlines(): if line.strip(): try: json_obj = json.loads(line) if "response" in json_obj: full_response += json_obj["response"] if json_obj.get("done", False): break except json.JSONDecodeError as e: logging.warning(f"JSON 解析错误: {e}, line: {line}") return clean_response(full_response.strip()) # 处理并去掉 <think>XXX</think> except requests.exceptions.RequestException as e: logging.error(f"请求失败: {e}") return "生成失败。"# 记录对话日志def log_conversation(user_id, question, question_embedding, retrieved_content, generated_answer): try: conn = pymysql.connect( host='X.X.X.X', port=9030, user='root', password='sr123456', database='knowledge_base' ) cursor = conn.cursor() embedding_str = "[" + ",".join(map(str, question_embedding)) + "]" sql = """ INSERT INTO customer_service_log (user_id, question, question_embedding, retrieved_content, generated_answer, timestamp) VALUES (%s, %s, %s, %s, %s, NOW()) """ cursor.execute(sql, (user_id, question, embedding_str, retrieved_content, generated_answer)) conn.commit() except pymysql.Error as db_err: logging.error(f"数据库错误: {db_err}") finally: cursor.close() conn.close()# 清理回答内容,去掉 <think>XXX</think>def clean_response(text): return re.sub(r"<think>.*?</think>", "", text, flags=re.DOTALL).strip()# RAG 处理流程def rag_pipeline(user_id,query): try: logging.info(f"开始处理查询: {query}") query_embedding = get_embedding(query) logging.info("获取嵌入向量成功") retrieved_content = search_knowledge_base(query_embedding) logging.info(f"检索到内容: {retrieved_content[:50]}...") # 只展示前50字符 prompt = build_rag_prompt(query, retrieved_content) generated_answer = generate_answer(prompt) logging.info(f"生成回答: {generated_answer[:50]}...") log_conversation(user_id, query, query_embedding, retrieved_content, generated_answer) logging.info("日志记录完成") return generated_answer except Exception as e: logging.error(f"发生错误: {e}", exc_info=True) return "处理失败。"# Flask API@app.route("/")def index(): return render_template("index.html") # 渲染前端页面@app.route("/ask", methods=["POST"])def ask(): user_id="sr_01" data = request.json question = data.get("question", "") result=rag_pipeline(user_id,question) answer = f"问题:{question}。\n 回答:{result}" return jsonify({"answer": answer})if __name__ == "__main__": user_id = "sr" app.run(host="0.0.0.0", port=9033, debug=True)
参考文档:
Deepseek 搭建:https://zhuanlan.zhihu.com/p/20803691410
Vector index 资料:https://docs.starrocks.io/zh/docs/table_design/indexes/vector_index/
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DeepSeek (深度求索)杭州深度求索(DeepSeek)官方推出的AI助手,免费体验与全球领先AI模型的互动交流。它通过学习海量的数据和知识,能够像人类一样理解和处理信息。多项性能指标对齐海外顶尖模型,用更快的速度、更加全面强大的功能答疑解惑,助力高效美好的生活。
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