Add PostgreSQL connection retry configuration options

- Add retry environment variables
- Fix asyncpg import in retry tests

env.example

@@ -303,6 +303,16 @@ POSTGRES_HNSW_M=16
 POSTGRES_HNSW_EF=200
 POSTGRES_IVFFLAT_LISTS=100
 
+### PostgreSQL Connection Retry Configuration (Network Robustness)
+### Number of retry attempts (1-10, default: 3)
+### Initial retry backoff in seconds (0.1-5.0, default: 0.5)
+### Maximum retry backoff in seconds (backoff-60.0, default: 5.0)
+### Connection pool close timeout in seconds (1.0-30.0, default: 5.0)
+# POSTGRES_CONNECTION_RETRIES=3
+# POSTGRES_CONNECTION_RETRY_BACKOFF=0.5
+# POSTGRES_CONNECTION_RETRY_BACKOFF_MAX=5.0
+# POSTGRES_POOL_CLOSE_TIMEOUT=5.0
+
 ### PostgreSQL SSL Configuration (Optional)
 # POSTGRES_SSL_MODE=require
 # POSTGRES_SSL_CERT=/path/to/client-cert.pem

tests/test_postgres_retry_integration.py

@@ -16,9 +16,10 @@ import os
 import time
 from dotenv import load_dotenv
 from unittest.mock import patch
-import asyncpg
 from lightrag.kg.postgres_impl import PostgreSQLDB
 
+asyncpg = pytest.importorskip("asyncpg")
+
 # Load environment variables
 load_dotenv(dotenv_path=".env", override=False)