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Oracle performance after migrating to BL860c i2

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Oracle performance after migrating to BL860c i2

We migrated a couple of databases from rx2660 (11iv3) to bl860c i2 (11iv3). The 10 and 11 versions of the databases are fine, but even a simple  query of v$sessions takes some time to respond on the version 9 database. The odd thing is, this only seems a problem with Windows clients. Running the same query on another hp-ux server (using TWO_TASK) is much faster. The latest ux patches are applied.  I have ran iostat, vmstat and sar -d while running the query from windows, but nothing unusual showed up. Does anyone has an idea in which direction I should look?



Honored Contributor

Re: Oracle performance after migrating to BL860c i2

Test the reverse DNS lookups:

  • Can the database server look up the name of the Windows client using the IP address of the client?
  • Can the Windows client look up the name of the database server using the IP address of the server?

You can test this with the "nslookup" command: it is available both in HP-UX and in the Windows command prompt.

Run "nslookup IP.address". The response should include:

  • The name and IP address of the DNS server providing the information
  • The IP address you requested information on
  • The name associated with the IP

If you find that the database server cannot look up the names of the Windows clients but can look up the other HP-UX server you used in your tests, or that the other HP-UX server can look up the database server but the Windows clients cannot, you may have found the cause.


If the old rx2660 database server (or its backup media) is still available, check its DNS configuration: /etc/resolv.conf, /etc/nsswitch.conf and /etc/hosts. 


Note: If you have one DNS server for Windows systems and another for HP-UX and they cannot access each other's information, you cannot use them both by simply listing them in /etc/resolv.conf. If the system asks one DNS server and gets a valid response saying "there is no name/IP associated with this IP/name" , the system won't ask for a second opinion from the other server: for the DNS protocol, the non-existence of the requested information is not an error, but a statement of fact, although in the negative sense. Errors would be something like "I am not allowed to tell you" or "I am unable to service you at the moment."


Re: Oracle performance after migrating to BL860c i2

MK, thanks for you're suggestion. The name resolving is ok. Only the Oracle 9 database has this problem, the other versions are working fine. Also connecting to the database is no problem. It looks like returning the results of a query  is the problem.




Re: Oracle performance after migrating to BL860c i2


We enabled tracing on sqlnet and found it was doing a lot of polling. While a SQL statement is running, SQL*Net polls the client continuously to catch CONTROL-C situations. This results into a lot of poll and fstat system calls.

In sqlnet.ora we set the parameter "BREAK_SKIP_POLL=10000" and this solved the problem. The system responses are normal now.


I do would like to know why enabling this parameter is necessary on Oracle9.2 on B.11.31.1103  (on BL860c i2) and not on B.11.31.0709 (rx2620).