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IC81752: JCC Driver connection slow due to JDK getHostName() and getCanon icalHostName() when NOT registed the IP ADDRESS in a DNS.

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APAR status

  • Closed as program error.

Error description

  • The following environment, getConnection may slow performance.
    
    DB2 server host information is NOT existed in /etc/hosts of DB2
    Client.
    DB2 Client host can lookup DNS host and DNS does not have an
    entry of
    DB2 server.
    
    ie)
    DB2 server host IP address is 192.168.107.155.
    # ping 192.168.107.155
    192.168.107.155 is alive
    
    NOT existed in /etc/hosts
    # grep -c 192.168.107.155 /etc/hosts
    0
    
    DB2 Client host can lookup DNS.
    # nslookup samplehost
    Server:         192.168.107.2
    Address:        192.168.107.2#53
    
    Non-authoritative answer:
    Name:
    Address: 192.168.107.200
    
    DNS does not have an entry of DB2 server.
    # nslookup 192.168.107.155
    Server:         192.168.107.2
    Address:        192.168.107.2#53
    
    ** server can't find 155.107.168.192.in-addr.arpa: NXDOMAIN
    
    In this case, getConnection may be slow responce, because DNS
    does not have reverse lookup record.
    
    We use getHostName() to get ip address from hostname.
    In JDK 1.4.2, changed getHostname behavior as below.
    
    If this InetAddress was created with a host name, this
    host name will be remembered and returned; otherwise, a reverse
    name lookup will be performed and the result will be returned
    based on the system configured name lookup service.
    

Local fix

  • Add entry in your DNS or /etc/hosts.
    

Problem summary

  • First fixed in JDBC driver from DB2 9.7 Fix Pack 7 (JCC driver
    version 3.64.106)
    

Problem conclusion

  • Upgrade to JDBC driver from DB2 9.7 Fix Pack 7 (JCC driver
    version 3.64.106) or higher
    

Temporary fix

Comments

APAR Information

  • APAR number

    IC81752

  • Reported component name

    DB2 FOR LUW

  • Reported component ID

    DB2FORLUW

  • Reported release

    950

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt / Xsystem

  • Submitted date

    2012-03-01

  • Closed date

    2017-05-19

  • Last modified date

    2017-05-19

  • APAR is sysrouted FROM one or more of the following:

  • APAR is sysrouted TO one or more of the following:

Fix information

  • Fixed component name

    DB2 FOR LUW

  • Fixed component ID

    DB2FORLUW

Applicable component levels

  • R970 PSY

       UP



Document information

More support for: DB2 for Linux, UNIX and Windows

Software version: 9.5

Reference #: IC81752

Modified date: 19 May 2017