Here is a quick post of a "quick and dirty" patch for the [ISC DNS] Server : Bind 9.5.0a6 and its dlz mysql driver. For the quick story, I was using [Bind] 9.4.1 with dlz MySQL. My [MySQL] server is a 5.0.41 (with [solidDB]). While using it, I realize that some times the dns server was returning empty value for the dns queries. I tried many tips but it was still (sometime) giving me empty answer... Of course, I suspected the dlz driver. So, I tried to upgrade to Bind 9.5.0a6 but the problem still happened and the only way to fix was to restart bind !