What is below will show SQL statements for a given window (the last four days in the example below) that are tightly correlated with load average on a server. In general, a statistical correlation greater than 60 means there is…
Author: Steve
A simple example of a custom component managed by CRS
You can add custom components to CRS if you have a need. You basically need a program (perhaps as simple as a shell script) that accepts three command line arguments: start stop check Below is an example of a shell…
Using awk with group by functionality
You can use the following example if you need to total numbers over a group in a given file. We first show our sample file… 14:30:57 oracle@emgrid01 ~ >cat list.txt steve:61 steve:14 becky:57 steve:19 jenna:69 stephen:57 maddie:54 jenna:53 abby:41 jenna:21…
Python script to print out table data in name/value pairs
Simple today. I just wanted to ensure I had this in case I need to cut and paste it later 🙂 #!/home/oracle/local/bin/python import cx_Oracle, string connection = cx_Oracle.connect(mode = cx_Oracle.SYSDBA) cursor = connection.cursor() cnt=cursor.execute(“select * from v$database”) colcount=len(cnt.description) for row…
Redo on unchanged column values
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…