I'm responding to an old thread I started back in March 2003. Today we had our ISP re-delegate reverse DNS for our domain. This included the IP range that holds both our application server (ODBC client) and SAPDB server (SAPDB 7.4.3 Build 027-123-048-452 on Windows 2000 Service Pack 4.
Forward DNS entries were all fine, it was reverse DNS entries that disappeared. The instant this change was made, our SAPDB server stopped responding to the application server. The SAPDB kernel just hung. Even after reboot it would not respond to client requests. One more observation to report: Even directly on the SAPDB server, local DBMCLI commands would not respond or respond very slowly (1 minute + timeout). I tried to do a DBMCLI info state command and it just sat there after the DBMCLI was issued. This is obviously without the use of drivers, direct with "-n localhost" param. We use only IP Addresses in our DSN-less client connection strings, no domain names. The FQDN and short names fully resolved for forward looking. As soon as we had our ISP put reverse DNS delegation back - things instantly worked. Our conclusion ================= SADPB 7.4.3.027 Kernel or XServer has a dependence on reverse DNS from the client. It will sit there waiting way too long for a DNS lookup and the kernel becomes unresponsive to this client. We find this behavior undesirable. A service like reverse DNS should not be essential to database operation. Especially when the two machines are on the same subnet (only one IP Address apart, on the same Ethernet switch). Is there a way to tweak Kernel or XServer? ================================================ I know one of the changelogs from earlier this year mentioned a parameter to XServer to reduce DNS dependence. Can someone review these parameters with us? On Windows 2000 is the proper procedure to add these parameters to the XServer service? Do these parameters address REVERSE DNS in addition to forward DNS? Thank you. Stephen Gutknecht -----Original Message----- From: Stephen Gutknecht (SAPDB) [mailto:[EMAIL PROTECTED] Sent: Friday, March 14, 2003 7:03 AM To: [EMAIL PROTECTED] Subject: SAPDB kernel on Win32 - DNS dependence on server names Hi, We have encountered some unusual problems with server performance that have at times pointed toward a DNS dependency within SAPDB. There are times when the server seems to stall when our connection to external DNS servers is lost. With SAPDB 7.4 (7.4.3 Build 014-120-037-952), I notice that backups and other things are referencing our server names by their reverse-DNS entry! In other words, instead of getting the hostname from Windows 2000, SAPDB is going out to our DNS server to get this entry. No where on the machine itself is this reverse-DNS on the machine, it can only be coming from a DNS lookup or special call to the OS. Can someone on the SAPDB team put some light on this? Thank you. Stephen Gutknecht _______________________________________________ sapdb.general mailing list [EMAIL PROTECTED] http://listserv.sap.com/mailman/listinfo/sapdb.general -- MaxDB Discussion Mailing List For list archives: http://lists.mysql.com/maxdb To unsubscribe: http://lists.mysql.com/[EMAIL PROTECTED]
