diff --git a/scripts/nas_sync/merge_increment.py b/scripts/nas_sync/merge_increment.py
index e980c08..92bd30f 100644
--- a/scripts/nas_sync/merge_increment.py
+++ b/scripts/nas_sync/merge_increment.py
@@ -30,6 +30,10 @@ def main():
 
     conn = sqlite3.connect(args.db)
     cur = conn.cursor()
+    # 大表(1.8亿行+)merge 提速: 默认2MB cache 致 UNIQUE索引(数GB)全磁盘IO, merge>120s超时
+    for _p in ("PRAGMA journal_mode=WAL", "PRAGMA synchronous=NORMAL",
+               "PRAGMA cache_size=-500000", "PRAGMA temp_store=MEMORY"):
+        cur.execute(_p)
     cur.execute(SCHEMA)
     cur.execute(
         "CREATE UNIQUE INDEX IF NOT EXISTS uq_dbbardata "
diff --git a/scripts/nas_sync/sync_dbbardata.sh b/scripts/nas_sync/sync_dbbardata.sh
index 473fa9c..f521040 100644
--- a/scripts/nas_sync/sync_dbbardata.sh
+++ b/scripts/nas_sync/sync_dbbardata.sh
@@ -26,7 +26,7 @@ DB=$ROOT/data_backup/quant_trading.db
 STAGE=$ROOT/data_backup/_staging
 STATE=$ROOT/data_backup/since.txt
 LOG=$ROOT/data_backup/sync.log
-STEP=20000000  # 全量分片步长（行/片，~2GB/片）
+STEP=2000000  # 全量分片步长（行/片，~200MB/片；首版2000万/2GB致首片export+scp跨公网挂,降至此）
 
 mkdir -p "$STAGE"
 LOG_TS="$(date '+%F %T')"