Oracle Tips Got Questions? KEEP pool deprecated in 12c 12c Poster Available! Free AWR Report Analysis BEWARE of 11gR2 Upgrade Gotchas! Search BC Oracle Sites Search Home Email Us Oracle Articles Oracle Training Oracle Tips Oracle Forum Class Catalog Remote DBA Oracle Tuning Emergency 911 RAC Support Apps Support Analysis Design Implementation Oracle Support SQL Tuning Security Oracle UNIX Oracle Linux Monitoring Remote support Remote plans Remote services Application Server Applications Oracle Forms Oracle Portal App Upgrades SQL Server Oracle Concepts Software Support Remote Support Development Implementation Consulting Staff Consulting Prices Oracle Partitioning Oracle Tips by Burleson Consulting Oracle partitioning is a divideandconquer approach to improving Oracle maintenance and SQL performance. Anyone with unpartitioned databases over 500 gigabytes is courting disaster. Databases become unmanageable, and serious problems occur: SQL may perform poorly Without Oracle partitioning, SQL queries with fulltable scans take hours to complete. In a full scan, the smaller the Oracle partition, the faster the performance. Also, index range scans become inefficient. Recovery Files recovery takes days, not minutes Maintenance Rebuilding indexes (important to reclaim space and improve performance) There are many compelling reasons to implement Oracle partitioning for larger databases, and Oracle partitioning has become the defacto standard for systems over 500 gigabytes. Oracle partitioning has many benefits to improve performance and manageability: Stable Oracle partitioning is a very stable technology and has been used in Oracle since Oracle8, back in 1997. Each new release of Oracle improves Oracle partitioning features. Robust ? Oracle partitioning allows for multilevel keys, a combination of the Range and List partitioning technique. The table is first range partitioned with Oracle partitioning, and then each individual range partition is further subpartitioned using a list partitioning technique with Oracle partitioning. Unlike composite RangeHash Oracle partitioning, the content of each subpartition represents a logical subset of the data, described by its appropriate Range and List Oracle partition setup. Faster backups A DBA can backup a single Oracle partition of a table, rather than backing up the entire table, thereby reducing backup time. Less overhead ? Because older Oracle partitioned tablespaces can be marked as readonly, Oracle has less stress on the redo logs, locks and latches, thereby improving overall performance. For more details, read Robert Freeman's discussion of readonly tablespace performance . Easier management ? Maintenance of Oracle partitioned tables is improved because maintenance can be focused on particular portions of tables. For maintenance operations across an entire database object, it is possible to perform these operations on a perpartition basis, thus dividing the maintenance process into more manageable chunks. Faster SQL ? Oracle is partitionaware, and some SQL may improve is speed by several orders of magnitude (over 100x faster). ��