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1. #ORACLE DATABASE TUTORIALS UPDATE#
2. #ORACLE DATABASE TUTORIALS FULL#
3. #ORACLE DATABASE TUTORIALS PROFESSIONAL#

We can also capture system statistics on the fixed data dictionary tables, which should be done during the regular workload and run once. Sqlplus> exec dbms_stats_gather_system_stats('Stop') gather for an hour during peak activity sqlplus> exec dbms_stats.gather_system_stats('Start') Capturing statistics at different times for various activities is especially useful when the workload on the database is different, such as batch processing or reporting at night and processing transactions during the day. The gathered statistics information is used by the cost-based optimizer to create query plans. In Oracle Database 10g, the GATHER_STATS_JOB job is scheduled to gather stale statistics and keep them updated. In Oracle, the parameter STATISTICS_LEVEL set to TYPICAL or ALL enables automatic statistics gathering.

#ORACLE DATABASE TUTORIALS UPDATE#

We can also run updates manually, using sp_updatestats or UPDATE STATISTICS. In SQL Server, the AUTO_UPDATE_STATISTICS database option, when turned on, will update the statistics when they become stale. In both SQL Server and Oracle, statistics are updated by default.

#ORACLE DATABASE TUTORIALS PROFESSIONAL#

This parameter is dynamic, so it can be altered to check its effects on your environment.Įnroll in this professional Oracle DBA Training to excel in your career! Health Checks

#ORACLE DATABASE TUTORIALS FULL#

This does add overhead to the system, but FULL is the only setting that will check for block corruption in the buffer cache. This setting will perform checksums on all changes before and after writing to the log. To have Oracle check the blocks in memory (the buffer cache), set DB_BLOCK_CHECKSUM to FULL. With more data movement possibly happening in memory, it is detecting the corruption here, before even writing to disk, is useful. The TYPICAL setting for this parameter (the default) verifies checksums before writing to disk. The DB_BLOCK_CHECKSUM parameter determines if blocks will be checked in memory. Oracle checks for block corruption as database writers handle the blocks of data. They can also validate the structures of objects and whether the tables and indexes still have corresponding values. Consistency checks look at the physical integrity of the data blocks and rows of objects. What is Database Maintenance Maintenance TasksĬonsistency checks validate database blocks and look for corruption in datafiles.