fix: 按完成时刻分批清理并限制读连接池

internal/store/db.go

@@ -7,6 +7,7 @@ import (
 	"os"
 	"path/filepath"
 	"strings"
+	"time"
 
 	_ "modernc.org/sqlite"
 )
@@ -134,6 +135,9 @@ func OpenReader(dataDir, synchronous string) (*sql.DB, error) {
 	if err != nil {
 		return nil, fmt.Errorf("open sqlite reader: %w", err)
 	}
+	db.SetMaxOpenConns(64)
+	db.SetMaxIdleConns(16)
+	db.SetConnMaxIdleTime(5 * time.Minute)
 	if err := db.Ping(); err != nil {
 		_ = db.Close()
 		return nil, fmt.Errorf("ping sqlite reader: %w", err)
@@ -157,6 +161,8 @@ func buildDSN(dataDir, synchronous string, writer bool) (string, error) {
 	)
 	if writer {
 		dsn += "&_txlock=immediate"
+	} else {
+		dsn += "&_pragma=query_only(1)"
 	}
 	return dsn, nil
 }