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OLTP vs OLAP

This page was updated on October 1, 1998



OLTP vs OLAP

Type of system OLTP System
Online Transaction Processing
(Operational System)
OLAP System
Online Analytical Processing
(Data Warehouse / Data Mart)
Source of data Operational data; OLTPs are the original source of the data Consolidation data; OLAP data comes from the various OLTP databases
Purpose of data To control and run fundamental business tasks To help with planning, problem solving, and decision support
What the data reveals A snapshot of ongoing business processes Multi-dimensional views of various kinds of business activities
Inserts and Updates Short and fast inserts and updates initiated by end users Periodic long-running batch jobs refresh the data
Queries Relatively standardized and simple queries returning relatively few records Often complex queries involving aggregations
Processing speed Typically very fast Depends on the amount of data involved; batch data refreshes and complex queries may take many hours; query speed can be improved by creating indexes
Space requirements Can be relatively small if historical data is archived Larger due to the existence of aggregation structures and history data; requires more indexes than OLTP
Database design Highly normalized with many tables Typically denormalized with fewer tables; use of star and/or snowflake schemas
Backup and recovery Backup religiously; operational data is critical to run the business, data loss is likely to entail significant monetary loss and legal liability Instead of regular backups, some environments may consider simply reloading the OLTP data as a recovery method


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