Database maintenance runs every day in a specific time slot. Database maintenance is an automatic process that optimizes the size of your database. Database maintenance is an automatic activity designed to keep a database running smoothly and well organized. The important aspect of maintaining databases is it keeps up the backup if anything happens there will be another same copy available. Some data basing systems are so good that it actually does this automatically, sending a backup to another system at a different location every day, every week, or even within any other set period of time.
These days different amazing systems for data basing are available hence can be used to build and maintain databases anywhere anytime, with one important example being MYSQL. When data are discarded, only the aggregated statistics are retained. At the time of maintenance of data collected for a certain period are aggregated and new statistical values, based on the aggregated data, are calculated. Maintenance can be only done by the people who are comfortable and familiar with the database system and the specifics of the particular database, although some maintenance tasks can be performed by people who do not have experience.
Keep in mind that the more granularity and the longer the retention period, the larger the database. Webomind, a database maintenance company, offers fully managed services to his clients.