fleet-memory/hindsight-api/hindsight_api/engine/search/retrieval.py
Nicolò Boschi 7445cef7b7
feat: add optional graph retriever MPFP (#26)
* feat: add optional graph retriever MPFP

* feat: add optional graph retriever MPFP
2025-12-12 16:58:50 +01:00

677 lines
24 KiB
Python

"""
Retrieval module for 4-way parallel search.
Implements:
1. Semantic retrieval (vector similarity)
2. BM25 retrieval (keyword/full-text search)
3. Graph retrieval (via pluggable GraphRetriever interface)
4. Temporal retrieval (time-aware search with spreading)
"""
from typing import List, Dict, Optional
from dataclasses import dataclass, field
from datetime import datetime
import asyncio
import logging
from ..db_utils import acquire_with_retry
from .types import RetrievalResult
from .graph_retrieval import GraphRetriever, BFSGraphRetriever
from .mpfp_retrieval import MPFPGraphRetriever
from ...config import get_config
logger = logging.getLogger(__name__)
@dataclass
class ParallelRetrievalResult:
"""Result from parallel retrieval across all methods."""
semantic: List[RetrievalResult]
bm25: List[RetrievalResult]
graph: List[RetrievalResult]
temporal: Optional[List[RetrievalResult]]
timings: Dict[str, float] = field(default_factory=dict)
temporal_constraint: Optional[tuple] = None # (start_date, end_date)
# Default graph retriever instance (can be overridden)
_default_graph_retriever: Optional[GraphRetriever] = None
def get_default_graph_retriever() -> GraphRetriever:
"""Get or create the default graph retriever based on config."""
global _default_graph_retriever
if _default_graph_retriever is None:
config = get_config()
retriever_type = config.graph_retriever.lower()
if retriever_type == "mpfp":
_default_graph_retriever = MPFPGraphRetriever()
logger.info("Using MPFP graph retriever")
elif retriever_type == "bfs":
_default_graph_retriever = BFSGraphRetriever()
logger.info("Using BFS graph retriever")
else:
logger.warning(f"Unknown graph retriever '{retriever_type}', falling back to MPFP")
_default_graph_retriever = MPFPGraphRetriever()
return _default_graph_retriever
def set_default_graph_retriever(retriever: GraphRetriever) -> None:
"""Set the default graph retriever (for configuration/testing)."""
global _default_graph_retriever
_default_graph_retriever = retriever
async def retrieve_semantic(
conn,
query_emb_str: str,
bank_id: str,
fact_type: str,
limit: int
) -> List[RetrievalResult]:
"""
Semantic retrieval via vector similarity.
Args:
conn: Database connection
query_emb_str: Query embedding as string
agent_id: bank ID
fact_type: Fact type to filter
limit: Maximum results to return
Returns:
List of RetrievalResult objects
"""
results = await conn.fetch(
"""
SELECT id, text, context, event_date, occurred_start, occurred_end, mentioned_at, access_count, embedding, fact_type, document_id, chunk_id,
1 - (embedding <=> $1::vector) AS similarity
FROM memory_units
WHERE bank_id = $2
AND embedding IS NOT NULL
AND fact_type = $3
AND (1 - (embedding <=> $1::vector)) >= 0.3
ORDER BY embedding <=> $1::vector
LIMIT $4
""",
query_emb_str, bank_id, fact_type, limit
)
return [RetrievalResult.from_db_row(dict(r)) for r in results]
async def retrieve_bm25(
conn,
query_text: str,
bank_id: str,
fact_type: str,
limit: int
) -> List[RetrievalResult]:
"""
BM25 keyword retrieval via full-text search.
Args:
conn: Database connection
query_text: Query text
agent_id: bank ID
fact_type: Fact type to filter
limit: Maximum results to return
Returns:
List of RetrievalResult objects
"""
import re
# Sanitize query text: remove special characters that have meaning in tsquery
# Keep only alphanumeric characters and spaces
sanitized_text = re.sub(r'[^\w\s]', ' ', query_text.lower())
# Split and filter empty strings
tokens = [token for token in sanitized_text.split() if token]
if not tokens:
# If no valid tokens, return empty results
return []
# Convert query to tsquery using OR for more flexible matching
# This prevents empty results when some terms are missing
query_tsquery = " | ".join(tokens)
results = await conn.fetch(
"""
SELECT id, text, context, event_date, occurred_start, occurred_end, mentioned_at, access_count, embedding, fact_type, document_id, chunk_id,
ts_rank_cd(search_vector, to_tsquery('english', $1)) AS bm25_score
FROM memory_units
WHERE bank_id = $2
AND fact_type = $3
AND search_vector @@ to_tsquery('english', $1)
ORDER BY bm25_score DESC
LIMIT $4
""",
query_tsquery, bank_id, fact_type, limit
)
return [RetrievalResult.from_db_row(dict(r)) for r in results]
async def retrieve_temporal(
conn,
query_emb_str: str,
bank_id: str,
fact_type: str,
start_date: datetime,
end_date: datetime,
budget: int,
semantic_threshold: float = 0.1
) -> List[RetrievalResult]:
"""
Temporal retrieval with spreading activation.
Strategy:
1. Find entry points (facts in date range with semantic relevance)
2. Spread through temporal links to related facts
3. Score by temporal proximity + semantic similarity + link weight
Args:
conn: Database connection
query_emb_str: Query embedding as string
agent_id: bank ID
fact_type: Fact type to filter
start_date: Start of time range
end_date: End of time range
budget: Node budget for spreading
semantic_threshold: Minimum semantic similarity to include
Returns:
List of RetrievalResult objects with temporal scores
"""
from datetime import timezone
# Ensure start_date and end_date are timezone-aware (UTC) to match database datetimes
if start_date.tzinfo is None:
start_date = start_date.replace(tzinfo=timezone.utc)
if end_date.tzinfo is None:
end_date = end_date.replace(tzinfo=timezone.utc)
entry_points = await conn.fetch(
"""
SELECT id, text, context, event_date, occurred_start, occurred_end, mentioned_at, access_count, embedding, fact_type, document_id, chunk_id,
1 - (embedding <=> $1::vector) AS similarity
FROM memory_units
WHERE bank_id = $2
AND fact_type = $3
AND embedding IS NOT NULL
AND (
-- Match if occurred range overlaps with query range
(occurred_start IS NOT NULL AND occurred_end IS NOT NULL
AND occurred_start <= $5 AND occurred_end >= $4)
OR
-- Match if mentioned_at falls within query range
(mentioned_at IS NOT NULL AND mentioned_at BETWEEN $4 AND $5)
OR
-- Match if any occurred date is set and overlaps (even if only start or end is set)
(occurred_start IS NOT NULL AND occurred_start BETWEEN $4 AND $5)
OR
(occurred_end IS NOT NULL AND occurred_end BETWEEN $4 AND $5)
)
AND (1 - (embedding <=> $1::vector)) >= $6
ORDER BY COALESCE(occurred_start, mentioned_at, occurred_end) DESC, (embedding <=> $1::vector) ASC
LIMIT 10
""",
query_emb_str, bank_id, fact_type, start_date, end_date, semantic_threshold
)
if not entry_points:
return []
# Calculate temporal scores for entry points
total_days = (end_date - start_date).total_seconds() / 86400
mid_date = start_date + (end_date - start_date) / 2 # Calculate once for all comparisons
results = []
visited = set()
for ep in entry_points:
unit_id = str(ep["id"])
visited.add(unit_id)
# Calculate temporal proximity using the most relevant date
# Priority: occurred_start/end (event time) > mentioned_at (mention time)
best_date = None
if ep["occurred_start"] is not None and ep["occurred_end"] is not None:
# Use midpoint of occurred range
best_date = ep["occurred_start"] + (ep["occurred_end"] - ep["occurred_start"]) / 2
elif ep["occurred_start"] is not None:
best_date = ep["occurred_start"]
elif ep["occurred_end"] is not None:
best_date = ep["occurred_end"]
elif ep["mentioned_at"] is not None:
best_date = ep["mentioned_at"]
# Temporal proximity score (closer to range center = higher score)
if best_date:
days_from_mid = abs((best_date - mid_date).total_seconds() / 86400)
temporal_proximity = 1.0 - min(days_from_mid / (total_days / 2), 1.0) if total_days > 0 else 1.0
else:
temporal_proximity = 0.5 # Fallback if no dates (shouldn't happen due to WHERE clause)
# Create RetrievalResult with temporal scores
ep_result = RetrievalResult.from_db_row(dict(ep))
ep_result.temporal_score = temporal_proximity
ep_result.temporal_proximity = temporal_proximity
results.append(ep_result)
# Spread through temporal links
queue = [(RetrievalResult.from_db_row(dict(ep)), ep["similarity"], 1.0) for ep in entry_points] # (unit, semantic_sim, temporal_score)
budget_remaining = budget - len(entry_points)
while queue and budget_remaining > 0:
current, semantic_sim, temporal_score = queue.pop(0)
current_id = current.id
# Get neighbors via temporal and causal links
if budget_remaining > 0:
neighbors = await conn.fetch(
"""
SELECT mu.id, mu.text, mu.context, mu.event_date, mu.occurred_start, mu.occurred_end, mu.mentioned_at, mu.access_count, mu.embedding, mu.fact_type, mu.document_id, mu.chunk_id,
ml.weight, ml.link_type,
1 - (mu.embedding <=> $1::vector) AS similarity
FROM memory_links ml
JOIN memory_units mu ON ml.to_unit_id = mu.id
WHERE ml.from_unit_id = $2
AND ml.link_type IN ('temporal', 'causes', 'caused_by', 'enables', 'prevents')
AND ml.weight >= 0.1
AND mu.fact_type = $3
AND mu.embedding IS NOT NULL
AND (1 - (mu.embedding <=> $1::vector)) >= $4
ORDER BY ml.weight DESC
LIMIT 10
""",
query_emb_str, current.id, fact_type, semantic_threshold
)
for n in neighbors:
neighbor_id = str(n["id"])
if neighbor_id in visited:
continue
visited.add(neighbor_id)
budget_remaining -= 1
# Calculate temporal score for neighbor using best available date
neighbor_best_date = None
if n["occurred_start"] is not None and n["occurred_end"] is not None:
neighbor_best_date = n["occurred_start"] + (n["occurred_end"] - n["occurred_start"]) / 2
elif n["occurred_start"] is not None:
neighbor_best_date = n["occurred_start"]
elif n["occurred_end"] is not None:
neighbor_best_date = n["occurred_end"]
elif n["mentioned_at"] is not None:
neighbor_best_date = n["mentioned_at"]
if neighbor_best_date:
days_from_mid = abs((neighbor_best_date - mid_date).total_seconds() / 86400)
neighbor_temporal_proximity = 1.0 - min(days_from_mid / (total_days / 2), 1.0) if total_days > 0 else 1.0
else:
neighbor_temporal_proximity = 0.3 # Lower score if no temporal data
# Boost causal links (same as graph retrieval)
link_type = n["link_type"]
if link_type in ("causes", "caused_by"):
causal_boost = 2.0
elif link_type in ("enables", "prevents"):
causal_boost = 1.5
else:
causal_boost = 1.0
# Propagate temporal score through links (decay, with causal boost)
propagated_temporal = temporal_score * n["weight"] * causal_boost * 0.7
# Combined temporal score
combined_temporal = max(neighbor_temporal_proximity, propagated_temporal)
# Create RetrievalResult with temporal scores
neighbor_result = RetrievalResult.from_db_row(dict(n))
neighbor_result.temporal_score = combined_temporal
neighbor_result.temporal_proximity = neighbor_temporal_proximity
results.append(neighbor_result)
# Add to queue for further spreading
if budget_remaining > 0 and combined_temporal > 0.2:
queue.append((neighbor_result, n["similarity"], combined_temporal))
if budget_remaining <= 0:
break
return results
async def retrieve_parallel(
pool,
query_text: str,
query_embedding_str: str,
bank_id: str,
fact_type: str,
thinking_budget: int,
question_date: Optional[datetime] = None,
query_analyzer: Optional["QueryAnalyzer"] = None,
graph_retriever: Optional[GraphRetriever] = None,
) -> ParallelRetrievalResult:
"""
Run 3-way or 4-way parallel retrieval (adds temporal if detected).
Args:
pool: Database connection pool
query_text: Query text
query_embedding_str: Query embedding as string
bank_id: Bank ID
fact_type: Fact type to filter
thinking_budget: Budget for graph traversal and retrieval limits
question_date: Optional date when question was asked (for temporal filtering)
query_analyzer: Query analyzer to use (defaults to TransformerQueryAnalyzer)
graph_retriever: Graph retrieval strategy (defaults to configured retriever)
Returns:
ParallelRetrievalResult with semantic, bm25, graph, temporal results and timings
"""
from .temporal_extraction import extract_temporal_constraint
temporal_constraint = extract_temporal_constraint(
query_text, reference_date=question_date, analyzer=query_analyzer
)
retriever = graph_retriever or get_default_graph_retriever()
if retriever.name == "mpfp":
return await _retrieve_parallel_mpfp(
pool, query_text, query_embedding_str, bank_id, fact_type,
thinking_budget, temporal_constraint, retriever
)
else:
return await _retrieve_parallel_bfs(
pool, query_text, query_embedding_str, bank_id, fact_type,
thinking_budget, temporal_constraint, retriever
)
@dataclass
class _SemanticGraphResult:
"""Internal result from semantic→graph chain."""
semantic: List[RetrievalResult]
graph: List[RetrievalResult]
semantic_time: float
graph_time: float
@dataclass
class _TimedResult:
"""Internal result with timing."""
results: List[RetrievalResult]
time: float
async def _retrieve_parallel_mpfp(
pool,
query_text: str,
query_embedding_str: str,
bank_id: str,
fact_type: str,
thinking_budget: int,
temporal_constraint: Optional[tuple],
retriever: GraphRetriever,
) -> ParallelRetrievalResult:
"""
MPFP retrieval with optimized parallelization.
Runs 2-3 parallel task chains:
- Task 1: Semantic → Graph (chained, graph uses semantic seeds)
- Task 2: BM25 (independent)
- Task 3: Temporal (if constraint detected)
"""
import time
async def run_semantic_then_graph() -> _SemanticGraphResult:
"""Chain: semantic retrieval → graph retrieval (using semantic as seeds)."""
start = time.time()
async with acquire_with_retry(pool) as conn:
semantic = await retrieve_semantic(
conn, query_embedding_str, bank_id, fact_type, limit=thinking_budget
)
semantic_time = time.time() - start
# Get temporal seeds if needed (quick query, part of this chain)
temporal_seeds = None
if temporal_constraint:
tc_start, tc_end = temporal_constraint
async with acquire_with_retry(pool) as conn:
temporal_seeds = await _get_temporal_entry_points(
conn, query_embedding_str, bank_id, fact_type,
tc_start, tc_end, limit=20
)
# Run graph with seeds
start = time.time()
graph = await retriever.retrieve(
pool=pool,
query_embedding_str=query_embedding_str,
bank_id=bank_id,
fact_type=fact_type,
budget=thinking_budget,
query_text=query_text,
semantic_seeds=semantic,
temporal_seeds=temporal_seeds,
)
graph_time = time.time() - start
return _SemanticGraphResult(semantic, graph, semantic_time, graph_time)
async def run_bm25() -> _TimedResult:
"""Independent BM25 retrieval."""
start = time.time()
async with acquire_with_retry(pool) as conn:
results = await retrieve_bm25(conn, query_text, bank_id, fact_type, limit=thinking_budget)
return _TimedResult(results, time.time() - start)
async def run_temporal(tc_start, tc_end) -> _TimedResult:
"""Temporal retrieval (uses its own entry point finding)."""
start = time.time()
async with acquire_with_retry(pool) as conn:
results = await retrieve_temporal(
conn, query_embedding_str, bank_id, fact_type,
tc_start, tc_end, budget=thinking_budget, semantic_threshold=0.1
)
return _TimedResult(results, time.time() - start)
# Run parallel task chains
if temporal_constraint:
tc_start, tc_end = temporal_constraint
sg_result, bm25_result, temporal_result = await asyncio.gather(
run_semantic_then_graph(),
run_bm25(),
run_temporal(tc_start, tc_end),
)
return ParallelRetrievalResult(
semantic=sg_result.semantic,
bm25=bm25_result.results,
graph=sg_result.graph,
temporal=temporal_result.results,
timings={
"semantic": sg_result.semantic_time,
"graph": sg_result.graph_time,
"bm25": bm25_result.time,
"temporal": temporal_result.time,
},
temporal_constraint=temporal_constraint,
)
else:
sg_result, bm25_result = await asyncio.gather(
run_semantic_then_graph(),
run_bm25(),
)
return ParallelRetrievalResult(
semantic=sg_result.semantic,
bm25=bm25_result.results,
graph=sg_result.graph,
temporal=None,
timings={
"semantic": sg_result.semantic_time,
"graph": sg_result.graph_time,
"bm25": bm25_result.time,
},
temporal_constraint=None,
)
async def _get_temporal_entry_points(
conn,
query_embedding_str: str,
bank_id: str,
fact_type: str,
start_date: datetime,
end_date: datetime,
limit: int = 20,
semantic_threshold: float = 0.1,
) -> List[RetrievalResult]:
"""Get temporal entry points (facts in date range with semantic relevance)."""
from datetime import timezone
if start_date.tzinfo is None:
start_date = start_date.replace(tzinfo=timezone.utc)
if end_date.tzinfo is None:
end_date = end_date.replace(tzinfo=timezone.utc)
rows = await conn.fetch(
"""
SELECT id, text, context, event_date, occurred_start, occurred_end, mentioned_at,
access_count, embedding, fact_type, document_id, chunk_id,
1 - (embedding <=> $1::vector) AS similarity
FROM memory_units
WHERE bank_id = $2
AND fact_type = $3
AND embedding IS NOT NULL
AND (
(occurred_start IS NOT NULL AND occurred_end IS NOT NULL
AND occurred_start <= $5 AND occurred_end >= $4)
OR (mentioned_at IS NOT NULL AND mentioned_at BETWEEN $4 AND $5)
OR (occurred_start IS NOT NULL AND occurred_start BETWEEN $4 AND $5)
OR (occurred_end IS NOT NULL AND occurred_end BETWEEN $4 AND $5)
)
AND (1 - (embedding <=> $1::vector)) >= $6
ORDER BY COALESCE(occurred_start, mentioned_at, occurred_end) DESC,
(embedding <=> $1::vector) ASC
LIMIT $7
""",
query_embedding_str, bank_id, fact_type, start_date, end_date, semantic_threshold, limit
)
results = []
total_days = max((end_date - start_date).total_seconds() / 86400, 1)
mid_date = start_date + (end_date - start_date) / 2
for row in rows:
result = RetrievalResult.from_db_row(dict(row))
# Calculate temporal proximity score
best_date = None
if row["occurred_start"] and row["occurred_end"]:
best_date = row["occurred_start"] + (row["occurred_end"] - row["occurred_start"]) / 2
elif row["occurred_start"]:
best_date = row["occurred_start"]
elif row["occurred_end"]:
best_date = row["occurred_end"]
elif row["mentioned_at"]:
best_date = row["mentioned_at"]
if best_date:
days_from_mid = abs((best_date - mid_date).total_seconds() / 86400)
result.temporal_proximity = 1.0 - min(days_from_mid / (total_days / 2), 1.0)
else:
result.temporal_proximity = 0.5
result.temporal_score = result.temporal_proximity
results.append(result)
return results
async def _retrieve_parallel_bfs(
pool,
query_text: str,
query_embedding_str: str,
bank_id: str,
fact_type: str,
thinking_budget: int,
temporal_constraint: Optional[tuple],
retriever: GraphRetriever,
) -> ParallelRetrievalResult:
"""BFS retrieval: all methods run in parallel (original behavior)."""
import time
async def run_semantic() -> _TimedResult:
start = time.time()
async with acquire_with_retry(pool) as conn:
results = await retrieve_semantic(conn, query_embedding_str, bank_id, fact_type, limit=thinking_budget)
return _TimedResult(results, time.time() - start)
async def run_bm25() -> _TimedResult:
start = time.time()
async with acquire_with_retry(pool) as conn:
results = await retrieve_bm25(conn, query_text, bank_id, fact_type, limit=thinking_budget)
return _TimedResult(results, time.time() - start)
async def run_graph() -> _TimedResult:
start = time.time()
results = await retriever.retrieve(
pool=pool,
query_embedding_str=query_embedding_str,
bank_id=bank_id,
fact_type=fact_type,
budget=thinking_budget,
query_text=query_text,
)
return _TimedResult(results, time.time() - start)
async def run_temporal(tc_start, tc_end) -> _TimedResult:
start = time.time()
async with acquire_with_retry(pool) as conn:
results = await retrieve_temporal(
conn, query_embedding_str, bank_id, fact_type,
tc_start, tc_end, budget=thinking_budget, semantic_threshold=0.1
)
return _TimedResult(results, time.time() - start)
if temporal_constraint:
tc_start, tc_end = temporal_constraint
semantic_r, bm25_r, graph_r, temporal_r = await asyncio.gather(
run_semantic(),
run_bm25(),
run_graph(),
run_temporal(tc_start, tc_end),
)
return ParallelRetrievalResult(
semantic=semantic_r.results,
bm25=bm25_r.results,
graph=graph_r.results,
temporal=temporal_r.results,
timings={
"semantic": semantic_r.time,
"bm25": bm25_r.time,
"graph": graph_r.time,
"temporal": temporal_r.time,
},
temporal_constraint=temporal_constraint,
)
else:
semantic_r, bm25_r, graph_r = await asyncio.gather(
run_semantic(),
run_bm25(),
run_graph(),
)
return ParallelRetrievalResult(
semantic=semantic_r.results,
bm25=bm25_r.results,
graph=graph_r.results,
temporal=None,
timings={
"semantic": semantic_r.time,
"bm25": bm25_r.time,
"graph": graph_r.time,
},
temporal_constraint=None,
)