Category: ‘Performance’

Grails Domain Class Reload Issuing Count Query

Aug 08 2012

When a Grails domain class is reloaded after a change, the Hibernate plugin for Grails verifies the domain class reloaded successfully by calling its count() method. Unfortunately, while somewhat rare, it is possible to have a domain class mapped to a very large table (or a view that joins very large tables) where a count […]

Oracle Exadata: Ensuring smart scan offload processing with “insert as select”

Apr 06 2012

One of the key performance enhancing features of Oracle Exadata Database is the offloading of query processing down to the storage layer. Only relevant rows and columns are returned to the database server. As a result, much less data travels over the Infiniband interconnect, dramatically improving the performance and concurrency of queries. However, there is […]

Import a subset of table columns using Oracle Data Pump

Mar 06 2012

Importing data is most efficient when you load only the columns you need into the target database. This becomes apparent when importing unnecessary LOB columns, which can slow down an import significantly. One method of limiting which columns to import is to first only export the columns you need. You can create a temporary table […]