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Administration: Optimizing Queries

Configuring Omnidex

Optimization Settings

Omnidex has two main configuration settings for controlling optimization of queries. The first option tells Omnidex which approaches it may use as needed to optimize a query. The second option tells Omnidex which approaches are required when optimizing a query, or else the query should not be processed.

OPTIMIZATION

The OPTIMIZATION setting controls the approaches available to Omnidex when it optimizes a query. This setting can be set using an option on the SELECT statement, or with a SET OPTIMIZATION command:

select ... with OPTIMIZATION='setting1,setting2,setting3,...'
set optimization setting1,setting2,setting3,...

The OPTIMIZATION settings are shown in the table below. The default setting is shown in bold.

Allow optimization Disallow optimization Description
QUAL NO_QUAL Omnidex can use indexes to perform qualifications, usually to process criteria in the WHERE clause.
AGGREGATION NO_AGGREGATION Omnidex can use indexes to perform aggregations, including grouped counts, distinct counts, sums, averages, mins and maxes.
ORDERBY NO_ORDERBY Omnidex can use indexes to perform ordering as required by the ORDER BY clause.
IDXRETRIEVAL NO_IDXRETRIEVAL Omnidex can use indexes to retrieve select items for the result set, avoiding access to the database.
CACHEQUAL NO_CACHEQUAL Omnidex can reuse qualifications from the previous query on this connection.
DISTINCT_KEY NO_DISTINCT_KEY Omnidex can perform aggregations against a QuickText index, and the result set represents an entry per keyword rather than an entry per row.
ROLLUP NO_ROLLUP Omnidex can redirect redirect the query to a Rollup Table for improved performance.
SORTMERGE NO_SORTMERGE Omnidex can perform a sort/merge join operation between two tables in order to improve performance.
HDC NO_HDC Omnidex can use a temporary Hashed Data Cache for improved performance.
LINK NO_LINK Omnidex can use indexes to perform table joins.
PRIKEY NO_PRIKEY Omnidex can favor using the underlying databases primary key indexes rather than using Omnidex indexes.
STARSCHEMA NO_STARSCHEMA Omnidex can perform intermediate aggregations in the fact table of a star schema prior to accessing the dimension tables.
UNRESTRICTEDQUAL NO_UNRESTRICTEDQUAL Omnidex can ignore the normal restrictions on special characters, embedded operators and other rules about criteria when performing qualifications.
NONE Omnidex should disable all optimizations when processing this query.
NO_ODX Omnidex should disable all optimizations that would involve Omnidex indexes when processing this query.

REQUIRED_OPTIMIZATION

Additional Resources

See also:

 
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admin/optimization/config/optimizations.1328658843.txt.gz ยท Last modified: 2016/06/28 22:38 (external edit)