While building a generic load testing toolkit, I found it useful to be able to use a standard invocation framework for running a thread class that contains the actual application code to be stress tested. However, I had some problems…
HBase JMX metrics
HBase exposes several metrics via JMX beans, some of which are similar to the Oracle performance counters recorded by AWR. Actually, they aren’t even *close* to what Oracle provides, but one can hope 🙂 Below is a simple example of…
Printing hadoop properties
The hadoop Configuration class implements the Iterable interface, so you can simply create a default configuration and list all properties, or pass a custom XML configuration file and print the properties from that. Below is a simple example. import java.util.*;…
ipcrm not removing SGA shared memory segment
Today, I had an issue I had seen before, but I can never remember how I fix it. As such, I wanted to document it here. Although rare, periodically an abnormally terminated instance will leave behind a shared memory segment.…
Flashback ability with HBase
Oracle has a great feature called flashback query. This allows a user to (try to) query a row as it existed at some point in the past. It provides this functionality by trying to find the necessary UNDO to reconstruct…
Printing all property values in an HBase configuration
I’m sure there is an easier (perhaps built-in) way to do this, but for now, I wanted to document how you can print all properties for a given configuration that you load into a JVM. import java.util.*; import org.apache.hadoop.hbase.*; import…