Red Hat NETWORK - USER 3.0 Guía de instalación descargar pdf (Pagina 70)

Chapter 8. Maintenance

Option Description

extend Increase the RHN Oracle tablespace

gather-stats PCT Gather statistics on RHN Oracle database objects. PCT

is the percentage of rows to estimate (the default is

15%).

report Reports on current usage of database space.

report-stats Reports on segments with stale or empty statistics.

restore DIRNAME Restores the database from backup kept in DIRNAME.

Database must be stopped for this command to run

successfully.

start Starts the database instance. This can also be

accomplished by issuing the service oracle

start command as root.

shrink-segments Shrinks RHN Oracle database segments with

signifcant amounts of free space.

status Shows the current status of the database, either

"running" or "offline".

stop Stops the database instance. This can also be

accomplished by issuing the service oracle stop

command as root.

tablesizes Show space report for each table

verify DIRNAME Verifies the contents of the backup kept in DIRNAME.

This command runs a checksum of each of the files

kept in the backup.

Note

Database statistics are collections of data that describe more details about the database and

the objects in the database. These statistics are used by the query optimizer to choose the best

execution plan for each SQL statement. Because the objects in a database can be constantly

changing, statistics must be regularly updated so that they accurately describe these database

objects. Statistics are maintained automatically by Oracle. However, if your database has

performance issues after a significant amount of data changes, consider performing manual

gathering of statistics.

Note

After deleting large amount of data, use the segment-shrink feature to reclaim fragmented

free space in an Oracle Database segment. The benefits of segment-shrink are compaction

of data that leads to better cache utilization and the compacted data requires fewer blocks to be

scanned in full table scans, which both lead to better performance.

The segment shrink feature works only on newly created Oracle Database 10g Release 2 that

comes with RHN Satellite Server 5.2.0. Due to different default database settings in Oracle

Database 9i this feature does not work on databases that were upgraded from previous RHN

Satellite Server releases.

1 2 ... 65 66 67 68 69 70 71 72 73 74 75 ... 85 86

Sin comentarios

Red Hat NETWORK - USER 3.0 Guía de instalación Pagina 70