feat(server-release): 从 main 迁移检索增强(章节聚类提升 + BM25 追加修复)

从 main 分支选择性提取检索质量增强代码,不含端口/API 配置变更:

- knowledge/base.py: BM25Index.add_documents 改为追加+去重模式,
  修复多文件上传后仅保留最后文件切片的覆盖 bug
- core/engine.py: 章节聚类提升(_section_cluster_boost)、词法匹配
  辅助种子资格(_chunk_lexical_score)、扩展参数优化
  (CONTEXT_EXPANSION_AFTER 5→8, MAX_EXPANDED_NEIGHBORS 4→8)
- api/chat_routes.py: 路由层词法匹配救援(_rescue_lexical_match)、
  章节聚类救援安全网(_rescue_section_cluster)

部署后需重建 BM25 索引:KnowledgeBaseManager().rebuild_bm25_index('public_kb')
This commit is contained in:
lacerate551
2026-06-17 17:49:36 +08:00
parent fc11b11dda
commit 87f3fae1aa
3 changed files with 390 additions and 14 deletions

View File

@@ -292,6 +292,198 @@ def _process_table_doc(doc: str, meta: Dict) -> str:
return doc
def _rescue_lexical_match(contexts: List[Dict], retrieval_query: str,
min_score: float) -> List[Dict]:
"""
词法匹配救援:当切片文本精确包含查询的核心关键词但 CrossEncoder 评分很低时,
将其分数提升至保底值,并同时救援同 source 下 chunk_index 相邻的切片。
适用场景:
1. 某个 section 只有一个正确切片(无法触发聚类救援)
2. 枚举类问题的 header 切片被词法匹配救援后,其后续子条目也应被一并保留
Args:
contexts: 全部上下文切片
retrieval_query: 检索查询
min_score: 最低分数阈值
Returns:
修改后的 contexts
"""
if not contexts or not retrieval_query:
return contexts
import re
from config import CLUSTER_RESCUE_FLOOR
# 清理查询:去除 markdown 格式和标点
clean_query = re.sub(r'\*+|#+|`', '', retrieval_query)
clean_query = re.sub(r'[?!。,,、;;:"""\'\s]+', ' ', clean_query).strip()
if len(clean_query) < 2:
return contexts
# 提取查询中的有意义 bigram连续两字组
query_bigrams = set()
for i in range(len(clean_query) - 1):
w = clean_query[i:i+2].strip()
if len(w) == 2:
query_bigrams.add(w)
if not query_bigrams:
return contexts
# Phase 1: 词法匹配救援——找到高分匹配的切片
rescued_seeds = [] # [(source, chunk_index)]
for ctx in contexts:
if ctx.get('score', 0) >= min_score:
continue
doc = ctx.get('doc', '') or ''
meta = ctx.get('meta', {})
section = meta.get('section', '') or meta.get('section_path', '')
combined = doc + ' ' + section
matched = sum(1 for w in query_bigrams if w in combined)
match_ratio = matched / len(query_bigrams)
if match_ratio > 0.35:
ctx['score'] = max(ctx.get('score', 0), CLUSTER_RESCUE_FLOOR)
source = meta.get('source', '')
chunk_index = meta.get('chunk_index')
if source and chunk_index is not None:
try:
rescued_seeds.append((source, int(chunk_index)))
except (ValueError, TypeError):
pass
# Phase 2: 邻居救援——对每个被词法匹配救援的种子,
# 同时救援同 source 下 chunk_index 后续相邻的切片(枚举子条目)
if rescued_seeds:
for source, seed_idx in rescued_seeds:
for ctx in contexts:
if ctx.get('score', 0) >= min_score:
continue
meta = ctx.get('meta', {})
if meta.get('source') != source:
continue
try:
n_idx = int(meta.get('chunk_index', -1))
except (ValueError, TypeError):
continue
# 救援种子后续 8 个相邻切片(覆盖大多数枚举/条款模式)
if seed_idx < n_idx <= seed_idx + 8:
ctx['score'] = max(ctx.get('score', 0), CLUSTER_RESCUE_FLOOR)
return contexts
def _normalize_section_for_rescue(section_path: str, levels: int = 2) -> str:
"""归一化 section_path取前 N 级路径用于分组"""
if not section_path:
return ''
parts = [p.strip() for p in section_path.split('>')]
return ' > '.join(parts[:levels])
def _rescue_section_cluster(contexts: List[Dict], retrieval_query: str,
min_score: float) -> List[Dict]:
"""
路由层章节聚类救援:当某个 section 有多个候选切片但全部低于 min_score 时,
给该 section 的切片分配保底分数,使其通过后续的 min_score 过滤。
作为引擎层 _section_cluster_boost 的二次安全网,防止极端情况下所有正确切片被过滤。
Args:
contexts: engine 返回的全部上下文切片(每个含 doc, meta, score
retrieval_query: 改写后的检索查询
min_score: 当前的最低分数阈值
Returns:
修改后的 contexts部分切片 score 被提升至保底分数)
"""
if not contexts:
return contexts
from config import (
CLUSTER_MIN_MEMBERS, CLUSTER_MIN_TYPES, CLUSTER_RESCUE_FLOOR,
CLUSTER_MAX_SECTIONS, CLUSTER_MAX_RESCUE_PER_SECTION,
CLUSTER_SECTION_PREFIX_LEVELS,
)
# 1. 按 (source, normalized_section) 分组
from collections import defaultdict
section_groups = defaultdict(list) # key → [index_in_contexts]
for i, ctx in enumerate(contexts):
meta = ctx.get('meta', {})
source = meta.get('source', '')
section_path = meta.get('section', '') or meta.get('section_path', '')
norm_section = _normalize_section_for_rescue(section_path, CLUSTER_SECTION_PREFIX_LEVELS)
if not source or not norm_section:
continue
key = (source, norm_section)
section_groups[key].append(i)
# 2. 检测"全灭 section"并计算聚类强度
rescue_candidates = [] # (strength, key, member_indices)
for key, indices in section_groups.items():
if len(indices) < CLUSTER_MIN_MEMBERS:
continue
# 检查是否所有成员都低于 min_score"全灭"
scores = [contexts[i].get('score', 0) for i in indices]
if any(s >= min_score for s in scores):
continue # 已有成员通过阈值,无需救援
# 计算聚类强度
chunk_types = set(contexts[i].get('meta', {}).get('chunk_type', 'text') for i in indices)
type_diversity = len(chunk_types)
if type_diversity < CLUSTER_MIN_TYPES:
continue # 类型不够多样,可能是噪音
# 查询与 section_path 的字符重叠率
source, norm_section = key
query_chars = set(retrieval_query)
section_chars = set(norm_section)
overlap = len(query_chars & section_chars) / max(len(query_chars), 1)
# 聚类强度 = 成员数 × 类型多样性 × (1 + 查询匹配度)
strength = len(indices) * type_diversity * (1.0 + overlap)
rescue_candidates.append((strength, key, indices))
# 3. 按强度降序,救援 top-N section
rescue_candidates.sort(key=lambda x: x[0], reverse=True)
rescued_sections = []
total_rescued = 0
for strength, key, indices in rescue_candidates[:CLUSTER_MAX_SECTIONS]:
# 对组内切片分配保底分数(仅低于 min_score 的)
rescue_count = 0
for idx in indices:
if rescue_count >= CLUSTER_MAX_RESCUE_PER_SECTION:
break
ctx = contexts[idx]
if ctx.get('score', 0) < min_score:
ctx['score'] = CLUSTER_RESCUE_FLOOR
rescue_count += 1
total_rescued += 1
if rescue_count > 0:
source, norm_section = key
rescued_sections.append({
'source': source,
'section': norm_section,
'members': len(indices),
'rescued': rescue_count,
'strength': round(strength, 2)
})
return contexts
def _order_text_contexts_for_prompt(contexts: List[Dict], query: str, max_chunks: int,
min_score: float = 0.0) -> List[Dict]:
"""
@@ -1635,7 +1827,8 @@ def rag():
DIRECT_CONTEXT_MAX_CHARS,
RERANK_CONTEXT_MIN_SCORE,
CONTEXT_MAX_CHARS, CONTEXT_SOFT_LIMIT,
CONFIDENCE_WARN_THRESHOLD, CONFIDENCE_CAUTION_THRESHOLD
CONFIDENCE_WARN_THRESHOLD, CONFIDENCE_CAUTION_THRESHOLD,
SECTION_CLUSTER_RESCUE_ENABLED
)
data = request.json or {}
@@ -2140,6 +2333,16 @@ def rag():
# 4. 构建 promptPhase 6LLM 图片感知)
# Bug 1 修复:文本切片用于 top 5 名额竞争,图片描述不参与竞争
# 词法匹配救援:当切片文本精确包含查询关键词但 CrossEncoder 评分低时,
# 提升分数使其通过 min_score 过滤(适用于独立切片无法触发聚类救援的场景)
contexts = _rescue_lexical_match(contexts, retrieval_query, RERANK_CONTEXT_MIN_SCORE)
# 章节聚类救援(路由层安全网):在 min_score 过滤前,
# 检测"全灭 section"并分配保底分数
if SECTION_CLUSTER_RESCUE_ENABLED:
contexts = _rescue_section_cluster(contexts, retrieval_query, RERANK_CONTEXT_MIN_SCORE)
text_contexts = _order_text_contexts_for_prompt(contexts, message, MAX_CONTEXT_CHUNKS,
min_score=RERANK_CONTEXT_MIN_SCORE)
# Phase 2按字符预算构建上下文

View File

@@ -77,6 +77,10 @@ try:
CONTEXT_EXPANSION_MAX_CHUNKS, ENUM_QUERY_DISABLE_TOPK_SHRINK, ENUM_QUERY_MMR_LAMBDA,
# Phase 3 扩展精细化
EXPANSION_SCORE_THRESHOLD, MAX_EXPANDED_NEIGHBORS,
# 章节聚类救援
SECTION_CLUSTER_BOOST_ENABLED, CLUSTER_MIN_MEMBERS, CLUSTER_MIN_TYPES,
CLUSTER_SEED_FLOOR, CLUSTER_MAX_BOOST_PER_SECTION, CLUSTER_MAX_SECTIONS,
CLUSTER_SECTION_PREFIX_LEVELS,
# 上下文与生成
LLM_TEMPERATURE, LLM_MAX_TOKENS, RECALL_MULTIPLIER,
# FAQ 与黑名单
@@ -102,10 +106,18 @@ except ImportError:
MMR_TOP_K = 30
CONTEXT_EXPANSION_ENABLED = True
CONTEXT_EXPANSION_BEFORE = 1
CONTEXT_EXPANSION_AFTER = 5
CONTEXT_EXPANSION_AFTER = 8
CONTEXT_EXPANSION_MAX_CHUNKS = 24
EXPANSION_SCORE_THRESHOLD = 0.3
MAX_EXPANDED_NEIGHBORS = 4
MAX_EXPANDED_NEIGHBORS = 8
# 章节聚类救援默认值
SECTION_CLUSTER_BOOST_ENABLED = True
CLUSTER_MIN_MEMBERS = 3
CLUSTER_MIN_TYPES = 2
CLUSTER_SEED_FLOOR = 0.35
CLUSTER_MAX_BOOST_PER_SECTION = 8
CLUSTER_MAX_SECTIONS = 3
CLUSTER_SECTION_PREFIX_LEVELS = 1
ENUM_QUERY_DISABLE_TOPK_SHRINK = True
ENUM_QUERY_MMR_LAMBDA = 0.85
DYNAMIC_RRF_ENABLED = True
@@ -733,11 +745,19 @@ class RAGEngine:
# 时间衰减Time Decay
fused_results = self._apply_time_decay(fused_results)
# 提前附加 _debug使聚类提升能写入调试步骤
fused_results['_debug'] = _debug
# ========== 章节聚类提升:在扩展前将低分但聚类的切片提升至种子阈值 ==========
if SECTION_CLUSTER_BOOST_ENABLED:
fused_results = self._section_cluster_boost(fused_results, query)
# ========== 上下文扩展补充强命中切片周围的连续文本rerank 之后,防止被截断)==========
# Phase 3仅对高分种子扩展邻居
before_exp = len(fused_results['ids'][0]) if fused_results.get('ids') else 0
fused_results = self._expand_contiguous_chunks(fused_results, top_k=top_k,
min_score=EXPANSION_SCORE_THRESHOLD)
min_score=EXPANSION_SCORE_THRESHOLD,
query=query)
after_exp = len(fused_results['ids'][0]) if fused_results.get('ids') else 0
_debug['steps'].append({'name': 'context_expansion', 'before': before_exp, 'after': after_exp})
@@ -1162,13 +1182,14 @@ class RAGEngine:
return self.collection
def _expand_contiguous_chunks(self, results: dict, top_k: int = None,
min_score: float = 0.0) -> dict:
min_score: float = 0.0, query: str = '') -> dict:
"""Add same-source same-section neighbor text chunks around strong hits.
Args:
results: 检索结果
top_k: 最大切片数
min_score: Phase 3 最低分数阈值,仅对 Rerank 分数高于此值的种子扩展
query: 查询文本,用于词法匹配辅助种子资格判定
"""
if not CONTEXT_EXPANSION_ENABLED:
return results
@@ -1198,7 +1219,7 @@ class RAGEngine:
seeds = [
(doc_id, doc, meta, dist)
for doc_id, doc, meta, dist in items[:base_limit]
if meta.get('chunk_type', 'text') == 'text'
if (meta.get('chunk_type', 'text') == 'text' or meta.get('_cluster_boosted'))
and meta.get('source')
and self._to_int(meta.get('chunk_index')) is not None
]
@@ -1210,7 +1231,11 @@ class RAGEngine:
# Phase 3跳过分数低于阈值的种子仅当 min_score > 0 时生效)
if min_score > 0 and seed_dist < min_score:
continue
# 词法匹配豁免CrossEncoder 低分但关键词重叠度高时仍允许作为种子
if query and self._chunk_lexical_score(_seed_doc, query) > 0.3:
pass # 词法匹配度高,允许作为种子
else:
continue
source = seed_meta.get('source')
section = seed_meta.get('section', '') or seed_meta.get('section_path', '')
@@ -1316,6 +1341,130 @@ class RAGEngine:
expanded[key] = results[key]
return expanded
@staticmethod
def _normalize_section_path(section_path: str, levels: int = None) -> str:
"""归一化 section_path取前 N 级路径,容忍 MinerU 标题检测误差。
例如: "第三章 吸烟场所的功能设置 > 第三条 文明吸烟...""第三章 吸烟场所的功能设置"
"""
if not section_path:
return ''
if levels is None:
levels = CLUSTER_SECTION_PREFIX_LEVELS
parts = [p.strip() for p in section_path.split('>')]
return ' > '.join(parts[:levels])
def _section_cluster_boost(self, results: dict, query: str = '') -> dict:
"""章节聚类提升:当同一 section 下多个切片text+table同时出现在候选集中
即使单个切片 CrossEncoder 分数很低,也将整组提升到种子阈值。
核心洞察:单个低分切片不可信,但同一 section 多个切片同时出现是强信号。
提升后的切片可以作为 _expand_contiguous_chunks 的种子,触发邻居扩展。
Args:
results: rerank 后的检索结果
query: 用户查询(用于后续扩展)
Returns:
修改后的 resultsdistances 被调整meta 中标记 _cluster_boosted
"""
if not results.get('ids') or not results['ids'][0]:
return results
ids = results['ids'][0]
metas = results.get('metadatas', [[]])[0]
distances = results.get('distances', [[]])[0] if results.get('distances') else None
if not distances:
return results
# 1. 按 (source, normalized_section) 分组
from collections import defaultdict
section_groups = defaultdict(list) # key → [(index, meta, dist)]
for i, (meta, dist) in enumerate(zip(metas, distances)):
source = meta.get('source', '')
section_path = meta.get('section', '') or meta.get('section_path', '')
norm_section = self._normalize_section_path(section_path)
if not source or not norm_section:
continue
key = (source, norm_section)
section_groups[key].append((i, meta, dist))
# 2. 检测聚类信号并提升
boost_target_dist = 1.0 - CLUSTER_SEED_FLOOR # score=0.35 → dist=0.65
boosted_sections = []
total_boosted = 0
# 按组成员数降序排列,优先处理最大聚类
sorted_groups = sorted(section_groups.items(), key=lambda x: len(x[1]), reverse=True)
for (source, norm_section), members in sorted_groups:
if len(boosted_sections) >= CLUSTER_MAX_SECTIONS:
break
# 聚类信号检测:成员数 >= 阈值 且 类型多样性 >= 阈值
chunk_types = set(m[1].get('chunk_type', 'text') for m in members)
if len(members) < CLUSTER_MIN_MEMBERS or len(chunk_types) < CLUSTER_MIN_TYPES:
continue
# 提升组内切片分数(仅提升低于阈值的)
boost_count = 0
for idx, meta, dist in members:
if boost_count >= CLUSTER_MAX_BOOST_PER_SECTION:
break
# 只提升分数低于种子阈值的切片(高分切片不需要)
if dist > boost_target_dist:
distances[idx] = boost_target_dist
meta['_cluster_boosted'] = True
boost_count += 1
total_boosted += 1
if boost_count > 0:
boosted_sections.append({
'source': source,
'section': norm_section,
'members': len(members),
'types': list(chunk_types),
'boosted': boost_count
})
# 3. 写 debug 信息
if boosted_sections:
debug_info = results.get('_debug', {})
if 'steps' not in debug_info:
debug_info['steps'] = []
debug_info['steps'].append({
'name': 'section_cluster_boost',
'sections': boosted_sections,
'total_boosted': total_boosted
})
results['_debug'] = debug_info
logger.info(f"[章节聚类提升] 提升 {total_boosted} 个切片,"
f"涉及 {len(boosted_sections)} 个 section: "
f"{[s['section'][:30] for s in boosted_sections]}")
return results
@staticmethod
def _chunk_lexical_score(chunk_text: str, query: str) -> float:
"""计算切片文本与查询的词法重叠度bigram 命中率),用于辅助种子资格判定。"""
if not chunk_text or not query:
return 0.0
import re
clean_q = re.sub(r'[?!。,,、;;:"""\'\s*#`]+', ' ', query).strip()
if len(clean_q) < 2:
return 0.0
bigrams = set()
for i in range(len(clean_q) - 1):
w = clean_q[i:i+2].strip()
if len(w) == 2:
bigrams.add(w)
if not bigrams:
return 0.0
matched = sum(1 for w in bigrams if w in chunk_text)
return matched / len(bigrams)
def _search_with_sub_queries(
self, original_query, sub_queries, top_k=5, allowed_levels=None,
role=None, department=None, collections=None, source_filter=None
@@ -1627,11 +1776,19 @@ class RAGEngine:
# 时间衰减
fused_results = self._apply_time_decay(fused_results)
# 提前附加 _debug使聚类提升能写入调试步骤
fused_results['_debug'] = _debug
# ========== 章节聚类提升:在扩展前将低分但聚类的切片提升至种子阈值 ==========
if SECTION_CLUSTER_BOOST_ENABLED:
fused_results = self._section_cluster_boost(fused_results, query)
# ========== 上下文扩展补充强命中切片周围的连续文本rerank 之后,防止被截断)==========
# Phase 3仅对高分种子扩展邻居
before_exp = len(fused_results['ids'][0]) if fused_results.get('ids') else 0
fused_results = self._expand_contiguous_chunks(fused_results, top_k=top_k,
min_score=EXPANSION_SCORE_THRESHOLD)
min_score=EXPANSION_SCORE_THRESHOLD,
query=query)
after_exp = len(fused_results['ids'][0]) if fused_results.get('ids') else 0
if _debug is not None:
_debug['steps'].append({'name': 'context_expansion', 'before': before_exp, 'after': after_exp})

View File

@@ -382,18 +382,34 @@ class BM25Index:
def add_documents(self, ids: List[str], documents: List[str], metadatas: List[dict]) -> None:
"""
添加文档到索引(会覆盖原有索引
添加文档到索引(追加模式,自动去重
如果 ID 已存在则更新对应文档,否则追加新文档。
添加后自动重建 BM25 索引。
Args:
ids: 文档 ID 列表
documents: 文档内容列表
metadatas: 文档元数据列表
"""
self.ids = ids
self.documents = documents
self.metadatas = metadatas
if documents:
tokenized = [self.tokenize(doc) for doc in documents]
# 建立已有 ID -> 索引位置 的映射,用于去重
existing_map = {doc_id: idx for idx, doc_id in enumerate(self.ids)}
for i, doc_id in enumerate(ids):
if doc_id in existing_map:
# 更新已有文档
pos = existing_map[doc_id]
self.documents[pos] = documents[i]
self.metadatas[pos] = metadatas[i]
else:
# 追加新文档
existing_map[doc_id] = len(self.ids)
self.ids.append(doc_id)
self.documents.append(documents[i])
self.metadatas.append(metadatas[i])
if self.documents:
tokenized = [self.tokenize(doc) for doc in self.documents]
self.bm25 = BM25Okapi(tokenized)
def search(self, query: str, top_k: int = 10) -> Tuple[List[str], List[str], List[dict], List[float]]: