Re: connection pools and listener log

From: Niall Litchfield <niall.litchfield_at_gmail.com>
Date: Sat, 26 Feb 2011 09:04:59 +0000
Message-ID: <AANLkTim_-SfR8M6J+GC-L-a=U_N39Wv2sRwt_UFGhcoe_at_mail.gmail.com>

at least on 11.2 - only version available on this machine - tnsping doens't result in an "established" line in listener.log but instead a ping line

Sat Feb 26 08:58:08 2011
26-FEB-2011 08:58:08 * ping * 0

I too have seen apps that persistently issue select sysdate from dual or equivalent to check whether the db is alive. Oddly they seem to be down more often than the database they are paranoid about and don't seem so concerned to check whether a file system is writeable before writing to it (but then as we all know only the database can fail right?).

I think (wildly) that Dave is seeing expected behaviour - AWR is persisting the logons stat (that is the number of times a new *database* logon occurs) whereas the listener is recording client connection requests, one would hope that most client connection requests actually get an existing database session to connect to (otherwise why use the pool). 10:1 ratio doesn't sound too bad to me.
On Sat, Feb 26, 2011 at 8:01 AM, Stephane Faroult <sfaroult_at_roughsea.com>wrote:

> Dave,
>
> I have seen in the past a lot of paranoid applications (application servers
> among others) regularly issuing dummy queries to check that the database is
> still here (I won't comment). Perhaps your application servers are happily
> issuing "tnsping" very often.
>
> Stephane Faroult
> RoughSea Ltd <http://www.roughsea.com/>
> Konagora <http://www.konagora.com/>
> RoughSea Channel on Youtube <http://www.youtube.com/user/roughsealtd>
>
> On 02/26/2011 12:46 AM, Herring Dave - dherri wrote:
>
> Folks,
>
> I'm trying to match up database logons with what I'm seeing in the local listener log and coming up way short, so hopefully one of you can enlighten me.
>
> Our configuration is Oracle 10gR2 on RHEL 4.6. There are a number of application servers that connect using a connection pool. I reviewed AWR "logons cumulative" statistic recently and saw that 1 instance regularly gets around 1,000 per hr. Checking the local listener log for "established" I found a number more like 10,000 per hour. How can that be? Don't "established" connections via the listener have to match up with the database "logons cumulative"? If not, what is it that's being sent by the application that the listener sees as a request to "establish" a connection but not really connect to the database?
>
> Thx.
>
> DAVID HERRING
> DBA
> Acxiom Corporation
> EML dave.herring_at_acxiom.com
> TEL 630.944.4762
> MBL 630.430.5988
> 1501 Opus Pl, Downers Grove, IL 60515, USAWWW.ACXIOM.COM <http://www.acxiom.com/>
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-- 
Niall Litchfield
Oracle DBA
http://www.orawin.info

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Received on Sat Feb 26 2011 - 03:04:59 CST