I recently spoke with an Oracle DBA. He mentioned they had a third party application that was generating gobs of redo by updating rows to their existing values, i.e., update t set c = c. This bothered me, as my…
Parsing hanganalyze output for blocking sessions
The hanganalyze command was introduced in Oracle 8i. It is very useful, especially to mere mortals like us. It is formatted in a human readable format. In contrast, a systemstate dump normally contains a lot of memory addresses and offsets,…
Converting SCN to decimal
I found a slick little script at the following URL for converting an SCN to decimal. http://www.bluegecko.net/oracle/converting-hexadecimal-oracle-scns-to-decimal/ You can take the raw SCN and substitute it below… scn=0x0623.02021908;echo $((${scn%%.*}*4294967296+0x${scn##*.}))
Yet another reason to use Oracle’s JDBC connection manager
Over the weekend we had an odd issue. We have four nodes in a cluster, with two core services. SERVICE_A runs on servers 1 and 2, while SERVICE_B runs on server 4. Server 3 is effectively idle most of the…
How to “unregister” a service from a listener
If a service is registered with your listener outside of the clusterware, you can unregister it with the following call: dbms_service.stop_service(service_name,instance_name) I verified that this will not disconnect existing sessions in the instance on which the service is being stopped.…
Is memory allocated actually in use?
In an earlier article, we talked about actually initializing memory rather than just allocating it. This post will show how we can look at what is allocated in Linux, as well as when it shows as being in use and…