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Oracle Tips by Burleson |
Oracle 10g AWR Physical Structures
AWR is stored in tables owned by ‘SYS’ but
physically located on the SYSAUX tablespace. The Workload Repository
contains two types of tables:
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Metadata Tables: These are used to
control, process, and describe the Workload Repository tables.
For example, Oracle uses the metadata tables to determine when
to perform snapshots, and what to capture to disk.
-
Historical
Statistics Tables: These tables store historical statistical
information about the database in the form of snapshots. Each
snapshot is a capture of the in–memory database statistics data
at a certain point in time. All names of the AWR tables are
prefixed with
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WRx$ with x specifying the kind of table:
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WRM$ tables store metadata information for the
Workload Repository.
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WRH$ tables store historical data or snapshots.
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WRI$ tables store data related to advisory
functions.
The WRx$ tables are organized into the
following categories: File Statistics, General System Statistics,
Concurrency Statistics, Instance Tuning Statistics, SQL Statistics,
Segment Statistics, Undo Statistics, Time– Model Statistics,
Recovery Statistics, and RAC Statistics. Fig 9.1 shows a graphical
view of the AWR table types.
Following is the list of WRM$ tables that
control all repository operations.
WRM$_BASELINE
WRM$_DATABASE_INSTANCE
WRM$_SNAPSHOT
WRM$_SNAP_ERROR
WRM$_WR_CONTROL
Dictionary views are also provided, making the
historical data available to users for query. Any view related to
the historical information in the AWR has the dba_hist_ prefix.
Figures 9.2 and 9.3 show the full list of the WR tables and the
dba_hist* tables respectively.
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