We installed Tomcat 6.0.39 (we weren’t running JDK 1.7), as well as hbase. To get this to work, we copied the following jar’s from the hadoop and hbase installation directories to the tomcat lib directory. -rw-r–r– 1 serengeti serengeti 5212641…
Category: Database
Why isn’t my cursor being shared?
This is a decent way to determine why a cursor isn’t being shared, resulting in cache locking during parsing (134 minutes total yesterday, which is very high historically)… SQL> select count(*),sql_id from gv$active_session_history where event = ‘library cache lock’ group…
Recreating diskgroup in an existing RAC
We created a diskgroup with normal redundancy, and were wasting half the space on the mirror as a result. We are completely striped and mirrored in EMC, so a mirror buys us no additional protection. We wanted to recreate the…
AWR like jobs in SQL Server
This morning when I arrived at the office, there were several emails related to a high CPU utilization issue on a SQL Server that occurred around 4:45AM this morning. Since SQL Server 2005 does not have the anticipated performance repository…
Finding rows that were locked, after the fact
In the Oracle database, if you have purchased the tuning pack, you have full access to the DBA_HIST_% views. AWR, or Automated Workload Repository, is normally accessed via grid control or another tool. However, the raw data in the DBA_HIST…
Setting TCPNODELAY on Oracle XA datasource in JBOSS
While troubleshooting performance problems, we wanted to test disabling Nagle’s algorithm in JBOSS with an Oracle XA datasource. We found that property was not configurable in the regular Oracle XA class. We ended up extending the Oracle class to set…
High latch free waits on Oracle XA transactions
We experienced large waits as well as the associated CPU spikes, when using distributed XA transactions in an ATG/JBOSS application server to Oracle database environment. Oracle “support” was, per usual, of absolutely no help is diagnosing the situation. I honestly…
Joining data in Pig
If you are an RDBMS person that is used to joining data from tables, you will be happy to know that this capability exists in Pig. Below is a very simple example. grunt> fs -cat /people 1,1,steve howard 2,1,becky howard…
Inserting full objects into a database column
I have never seen the need for this, but I like to understand things in case I ever run across them “in the wild”. I did see it in a commercial ecommerce application in which the designers serialized an “Order”…
Cloudera Impala simple command line test
I am a big believer in simple command line examples. Connecting the dots is so much easier when you do this. There will be much more on this, but this should get you started. CLASSPATH is shown below. The absolute…