IBM Support

SE60917 - OSP-DB DNS LOOKUP DELAY FOR SQL CONNECT

 APAR (Authorized Program Analysis Report)

Abstract

OSP-DB DNS LOOKUP DELAY FOR SQL CONNECT

Error Description

getnameinfo() done in QSQCONN in RWCNNATT expansion leading to  
poor performance when DNS delays returning the host name.      
                                                               
Fix is to not do the getnameinfo() at *SET time but rather at  
*RETRIEVE time for ?RWCNNATT.                                  
This way the expense of the lookup isn't incurred everytime    
QSQCONN is called, but rather when the user references          
CLIENT_HOST.                                                    

Problem Summary

SQL Performance problem during connect due to getnameinfo() call
in QSQCONN exacerbated by poor performing DNS.  This call is to
retrieve the built-in global variable CLIENT_HOST value.        

Problem Conclusion

Remove getnameinfo() call from connect path (QSQCONN) and move  
it into global variable path so that when CLIENT_HOST is        
requested, the DNS lookup expense is incurred for those that use
the variable.                                                  

Temporary Fix

Comments

Circumvention


PTFs Available

R720 SI55641 PTF Cover Letter   5135

Affected Modules

         
         

Affected Publications

Summary Information

Status............................................ CLOSED PER
HIPER........................................... No
Component.................................. 5770SS1DB
Failing Module.......................... RCHMGR
Reported Release................... R720
Duplicate Of..............................




System i Support

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Document information

More support for: i family

Software version: V7R2M0

Operating system(s): OS/400

Reference #: SE60917

Modified date: 30 May 2015