DBMS_AVTUNE

40 DBMS_AVTUNE

The DBMS_AVTUNE package analyzes query access levels and aggregation workloads for each auto-cache enabled analytic view (AV) and creates or drops AV auto-caches to improve the overall performance of the SQL queries on that AV.

This chapter contains the following topics:

DBMS_AVTUNE Overview

This package allows you to create a cache on an existing AV. It also enables the AV for auto caching. You can also create, refresh, and remove a star cache.

Usage Notes

It is intended that the owner of the AV is also the user calling this package. Calling this package on an AV in another schema is not supported.
Before you use any other procedure in this package, you need to call the AUTO_CACHE_ENABLE procedure. After the AV is enabled, auto-tuning will continue till the AV is disabled. You can call any other procedures on an enabled AV to manually tune the AV for more fine-grained control of the performance.

DBMS_AVTUNE Security Model

The DBMS_AVTUNE package runs under AUTHID CURRENT_USER. The SQL generated through use of the package is executed as the current user, and EXECUTE privilege on the package is granted to PUBLIC.

Summary of DBMS_AVTUNE Subprograms

This table lists the DBMS_AVTUNE package subprograms and briefly describes them.

Table 40-1 DBMS_AVTUNE Package Subprograms

Procedure	Description
AUTO_CACHE_CREATE Procedure	This procedure creates a cache on an existing analytic view.
AUTO_CACHE_DISABLE Procedure	This procedure disables an analytic view for auto caching and removes all auto-caches.
AUTO_CACHE_ENABLE Procedure	This procedure enables analytic views for auto caching and sets auto-cache settings for analytic views. This procedure throws an error if the AV is already enabled.
AUTO_CACHE_MODIFY Procedure	This procedure modifies tuning parameters originally supplied in the enable call.
AUTO_CACHE_REFRESH Procedure	This procedure forces a refresh immediately of all auto-caches for the analytic view.
AUTO_CACHE_REMOVE Procedure	This procedure manually removes the auto-cache defined for the specified levels.
AUTO_CACHE_TUNE Procedure	This procedure forces the tuning process to run immediately for the analytic view and implement changes.
AUTO_CACHE_STAR_DISABLE Procedure	This procedure removes the star cache on the attribute dimension `dim_name`.
AUTO_CACHE_STAR_ENABLE Procedure	This procedure creates a star cache on the atttribute dimension `dim_name`.
AUTO_CACHE_STAR_MODIFY Procedure	This procedure modifies the parameters specified in the enable call.
AUTO_CACHE_STAR_REFRESH Procedure	This procedure refreshes the star cache for the attribute dimension dim_name.

AUTO_CACHE_CREATE Procedure

This procedure creates a cache on an existing analytic view.

Syntax

DBMS_AVTUNE.AUTO_CACHE_CREATE (
    av_name        IN  VARCHAR2,
    level_group    IN  LEVEL_LIST,
    av_owner       IN  VARCHAR2);

Parameters

Table 40-2 AUTO_CACHE_CREATE Procedure Parameters

Parameter	Description
`av_name`	The name of the analytic view.
`level_group`	Represents the levels to cache.
`av_owner`	The owner of the AV, defaulting to the current schema.

Example

execute dbms_avtune.auto_cache_create('UNITS_HCUBE_AVTUNE', 
  dbms_avtune.level_list(dbms_avtune.level('PRODUCT', 'ROLLUP', 'CLASS'),
  dbms_avtune.level('TIME', 'CALENDAR', 'YEAR')));

AUTO_CACHE_DISABLE Procedure

This procedure disables an analytic view for auto caching and removes all auto-caches.

Syntax

DBMS_AVTUNE.AUTO_CACHE_DISABLE (
    av_name        IN  VARCHAR2,
    av_owner       IN  VARCHAR2);

Parameters

Table 40-3 AUTO_CACHE_DISABLE Procedure Parameters

Parameter	Description
`av_name`	The name of the analytic view to disable caching on.
`av_owner`	The owner of the AV, defaulting to the current schema.

AUTO_CACHE_ENABLE Procedure

This procedure enables analytic views for auto caching and sets auto-cache settings for analytic views. This procedure throws an error if the AV is already enabled. It is not possible to update an already enabled AV using this procedure.

Syntax

DBMS_AVTUNE.AUTO_CACHE_ENABLE (
    av_name           IN   VARCHAR2,
    refresh_intvl     IN   NUMBER,
    num_queries       IN   NUMBER,
    avg_query_time    IN   NUMBER,
    total_cache_pct   IN   NUMBER,
    init_max_pct      IN   NUMBER,
    init_numhier      IN   NUMBER,
    init_fixed_lvls   IN   LEVEL_LIST,
    run_mode          IN   VARCHAR2,
    av_owner          IN   VARCHAR2);

Parameters

Table 40-4 AUTO_CACHE_ENABLE Procedure Parameters

Parameter	Description
`av_name`	The name of the analytic view to enable caching on.
`refresh_intvl`	The number of minutes to wait between each cache refresh. The default value is 10 minutes.
`num_queries`	The minimum number of queries to consider for caches. The default value is 1.
`avg_query_time`	The average number of seconds each query should take before being considered for caches. The default value is 3.
`total_cache_pct`	The maximum percentage of the fact table you wish to cache. The default value is 50.
`init_max_pct`	The maximum percentage of the fact table for the initial cache. The default value is 1%.
`init_numhier`	The maximum number of hierarchies to use for each dimension in the initial cache.
`init_fixed_lvls`	The levels you definitely want in the initial cache.
`run_mode`	This parameter is not used. Always use the default value.
`av_owner`	The owner of the AV, defaulting to the current schema.

AUTO_CACHE_MODIFY Procedure

This procedure modifies the tuning parameters originally supplied in the enable call. The parameters remain unchanged if NULL is specified.

Syntax

DBMS_AVTUNE.AUTO_CACHE_MODIFY (
    av_name           IN   VARCHAR2,
    refresh_intvl     IN   NUMBER,
    num_queries       IN   NUMBER,
    avg_query_time    IN   NUMBER,
    total_cache_pct   IN   NUMBER,
    av_owner          IN   VARCHAR2);

Parameters

Table 40-5 AUTO_CACHE_MODIFY Procedure Parameters

Parameter	Description
`av_name`	The name of the analytic view to enable caching on.
`refresh_intvl`	The number of minutes to wait between each cache refresh. The default value is `10` minutes.
`num_queries`	The minimum number of queries to consider for caches. The default value is `1`.
`avg_query_time`	The average number of seconds each query should take before being considered for caches. The default value is `3`.
`total_cache_pct`	The maximum percentage of the fact table you wish to cache. The default value is `50`.
`av_owner`	The owner of the AV, defaulting to the current schema.

AUTO_CACHE_REFRESH Procedure

This procedure forces a refresh immediately of all auto-caches for the analytic view.

Syntax

DBMS_AVTUNE.AUTO_CACHE_REFRESH (
    av_name           IN   VARCHAR2,
    av_owner          IN   VARCHAR2);

Parameters

Table 40-6 AUTO_CACHE_REFRESH Procedure Parameters

Parameter	Description
`av_name`	The name of the analytic view.
`av_owner`	The owner of the AV, defaulting to the current schema.

AUTO_CACHE_REMOVE Procedure

This procedure manually removes the auto-cache defined for the specified levels.

Syntax

DBMS_AVTUNE.AUTO_CACHE_REMOVE (
    av_name        IN  VARCHAR2,
    level_group    IN  LEVEL_LIST,         
    av_owner       IN  VARCHAR2);

Parameters

Table 40-7 AUTO_CACHE_REMOVE Procedure Parameters

Parameter	Description
`av_name`	The name of the analytic view.
`level_group`	Represents the levels to cache.
`av_owner`	The owner of the AV, defaulting to the current schema.

AUTO_CACHE_TUNE Procedure

This procedure forces the tuning process to run immediately for the analytic view and implement changes.

Syntax

DBMS_AVTUNE.AUTO_CACHE_TUNE (
    av_name           IN   VARCHAR2,
    num_queries       IN   NUMBER,
    avg_query_time    IN   NUMBER,
    run_mode          IN   VARCHAR2,
    av_owner          IN   VARCHAR2);

Parameters

Table 40-8 AUTO_CACHE_TUNE Procedure Parameters

Parameter	Description
`av_name`	The name of the analytic view.
`num_queries`	The minimum number of queries to consider for caches. The default value is `1`.
`avg_query_time`	The average number of seconds each query should take before being considered for caches. The default value is `3`.
`run_mode`	The `run_mode` parameter is not used. Always use the default value.
`av_owner`	The owner of the AV, defaulting to the current schema.

AUTO_CACHE_STAR_DISABLE Procedure

This procedure removes the star cache on the attribute dimension dim_name.

Syntax

DBMS_AVTUNE.AUTO_CACHE_STAR_DISABLE (
    dim_name       IN   VARCHAR2,
    dim_owner      IN   VARCHAR2);

Parameters

Table 40-9 AUTO_CACHE_STAR_DISABLE Procedure Parameters

Parameter	Description
`dim_name`	The name of the attribute dimension.
`dim_owner`	The owner of the attribute dimension.

AUTO_CACHE_STAR_ENABLE Procedure

This procedure creates a star cache on the atttribute dimension dim_name. The av_name can optionally be passed to qualify the attribute dimension.

Syntax

DBMS_AVTUNE.AUTO_CACHE_STAR_ENABLE (
    dim_name          IN   VARCHAR2,
    av_name           IN   VARCHAR2,
    refresh_intvl     IN   NUMBER,
    run_mode          IN   VARCHAR2,
    dim_owner         IN   VARCHAR2,
    av_owner          IN   VARCHAR2);

Parameters

Table 40-10 AUTO_CACHE_STAR_ENABLE Procedure Parameters

Parameter	Description
`dim_name`	The name of the attribute dimension.
`av_name`	The name of the AV to associate the star cache with, if any. The `av_name` can optionally be specified to associate the star cache with the given AV. When this is done then the star cache will be refreshed and maintained with the AV instead of independently.
`refresh_intvl`	The number of minutes to wait between each cache refresh. The default value is `10` minutes.
`run_mode`	This parameter is not used. Always use the default value.
`dim_owner`	The owner of the attribute dimension.
`av_owner`	The owner of the AV, defaulting to the current schema.

AUTO_CACHE_STAR_MODIFY Procedure

This procedure modifies the parameters specified in the enable call. The parameters remain unchanged if NULL is specified.

Syntax

DBMS_AVTUNE.AUTO_CACHE_STAR_MODIFY (
    dim_name          IN   VARCHAR2,
    av_name           IN   VARCHAR2,
    refresh_intvl     IN   NUMBER,
    dim_owner         IN   VARCHAR2,
    av_owner          IN   VARCHAR2);

Parameters

Table 40-11 AUTO_CACHE_STAR_MODIFY Procedure Parameters

Parameter	Description
`dim_name`	The name of the attribute dimension.
`av_name`	The name of the associated analytic view.
`refresh_intvl`	The number of minutes to wait for each cache refresh. The default value is `10` minutes.
`dim_owner`	The owner of the attribute dimension.
`av_owner`	The owner of the AV, defaulting to the current schema.

AUTO_CACHE_STAR_REFRESH Procedure

This procedure refreshes the star cache for the attribute dimension dim_name.

Syntax

DBMS_AVTUNE.AUTO_CACHE_STAR_REFRESH (
    dim_name       IN   VARCHAR2,
    dim_owner      IN   VARCHAR2);

Parameters

Table 40-12 AUTO_CACHE_STAR_REFRESH Procedure Parameters

Parameter	Description
`dim_name`	The name of the attribute dimension.
`dim_owner`	The owner of the attribute dimension.