Justifying Oracle Partitioning

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). ��


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Transcript of Justifying Oracle Partitioning

7/8/2015 Justifying Oracle partitioning

http://www.dba­oracle.com/oracle_tips_partitioning.htm 1/3

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 Oracle Partitioning

Oracle Tips by Burleson Consulting

Oracle partitioning is a divide­and­conquer approach to improving Oraclemaintenance and SQL performance.  Anyone with un­partitioned databases over500 gigabytes is courting disaster.  Databases become unmanageable, and seriousproblems occur: 

SQL may perform poorly ­ Without Oracle partitioning, SQL querieswith full­table scans take hours to complete.  In a full scan, the smaller theOracle partition, the faster the performance.  Also, index range scansbecome inefficient.

Recovery ­ Files recovery takes days, not minutes

Maintenance ­ Rebuilding indexes (important to re­claim space andimprove performance)

There are many compelling reasons to implement Oracle partitioning for largerdatabases, and Oracle partitioning has become the de­facto standard for systemsover 500 gigabytes.  Oracle partitioning has many benefits to improveperformance and manageability:

Stable ­ Oracle partitioning is a very stable technology and has been usedin Oracle since Oracle8, back in 1997.  Each new release of Oracleimproves Oracle partitioning features.

Robust ? Oracle partitioning allows for multi­level keys, a combination ofthe Range and List partitioning technique. The table is first range­partitioned with Oracle partitioning, and then each individual range­partition is further sub­partitioned using a list partitioning technique withOracle partitioning. Unlike composite Range­Hash Oracle partitioning, thecontent 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 bemarked as read­only, Oracle has less stress on the redo logs, locks andlatches, thereby improving overall performance.  For more details, readRobert Freeman's discussion of read­only tablespace performance.

Easier management ? Maintenance of Oracle partitioned tables isimproved because maintenance can be focused on particular portions oftables. For maintenance operations across an entire database object, it ispossible to perform these operations on a per­partition basis, thus dividingthe maintenance process into more manageable chunks.

Faster SQL ? Oracle is partition­aware, and some SQL may improve isspeed by several orders of magnitude (over 100x faster).


7/8/2015 Justifying Oracle partitioning

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­ Index range scans ? Oracle partitioning physicallysequences rows in index­order causing a dramaticimprovement (over 10x faster) in the speed of partition­key scans.

­  Full­table scans ? Oracle partition pruning onlyaccesses those data blocks required by the query.

­  Table joins ? Oracle partition­wise joins take thespecific sub­set of the query partitions, causing hugespeed improvements on nested loop and hash joins.

­  Updates ? Oracle parallel query for partitionsimproves batch load speed.

In sum, Oracle partitioning has a very­fast payback time and the immediateimprovements to performance and stress reduction on the Oracle server makes ita slam­dunk decision.

Please see related partitioning pages:

Oracle partitioning methods

oracle partitioning tips

Oracle Partitioning

Oracle interval partitioning tips

Oracle Partition Key Statistics & tuning


 If you like Oracle tuning, see the book "Oracle Tuning:The Definitive Reference", with 950 pages of tuning tipsand scripts. 

You can buy it direct from the publisher for 30%­off andget instant access to the code depot of Oracle tuningscripts.


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