measuring performance of scan listeners

From: Dba DBA <>
Date: Wed, 2 Apr 2014 12:51:47 -0400
Message-ID: <>

Clusterware(2 nodes):
DB Homes:,, 11.2.4 (all use same clusterware) OS: Redhat 6.

Migrating existing DBs from a customer to us. Our standard is to use SCAN listener. The customer uses 1 listener per DB. This is primarily because DBs upgraded from earlier versions. Its a much larger project to require TNS changes to many locations if you change to scan. In our case all tns needs to change because we are moving to different servers.

Getting pushback about 'performance issues with just the scan listener'. I dont know how to measure this. Its outside the DB so the event system won't work. I don't think it matters since its the same set of CPUs, but Id rather get some numbers instead of guessing.

We are also required to use SSL connections and plan to follow the following note. Not sure if this has any impact on performance.

 [image: Description:]

*Using Class of Secure Transport (COST) to Restrict Instance Registration in Oracle RAC (Doc ID 1340831.1)*

1. Some clusters have 20+ DBs. Concern(not my concern) is that scan listener alone can't handle this many DBs.

2. SSL connections: I think the customer actually set this up wrong. They had the TCPS configured in the listener, but gave their users the TCP connection. So they are not really using SSL. For security reasons, I made the decision to use SSL across the board and do it correctly. I dont know if this has any impact on performance and I dont know how to measure it.

3. Some DBs have very high process parameters (over 1100). This implies these DBs have applications that don't use connection pooling. So this would mean more listener usage. I dont know for sure. All I have to go on is the init.ora file. We are in the early stages. I also would be surprised if this matters to scan vs. lots of listeners.

I dont think going to scan will impact performance. Its the same number of CPUs. I think lots of listeners may be a little worse since its more processes that need to be spawned. That being said, I have no idea how to measure this. Its outside the DB, so the DB event system won't work.

Any suggestions on how to measure 'listener performance'. It sounds bizarre, but I don't know how to respond.

Received on Wed Apr 02 2014 - 18:51:47 CEST

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