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Sample history table Explain queries

Before you can run these queries, you must first have run an Explain with the HISTORY parameter set to YES, and the RETAIN parameter set to a number greater than zero.

For instructions about running the query, see the comment in each query member.

Note

Verify the creator name for the aliases that were used when installing SQL Explorer. You must use this creator name as the alias qualifier in the SET CURRENT SQLID statement in each query. Use the query PSSGETAL to locate the alias qualifier.

The following members are delivered in the hlq.llqSAMP data set:

Query member

Description

PSSGETAL

Finds the alias to use for the SQL Explorer history table

PSSHYBRD

Finds queries performing hybrid joins, which are normally poor performers

PSSIXCNT

Returns a count of the number of rows using a specified index

PSSIXNOM

Finds queries performing nonmatching index scans

PSSIXPTM

Finds queries where match columns are not equal to all index columns

PSSIXRAT

Finds queries where the cluster ratio is less than a specified percent

PSSLPREF

Finds queries using list prefetch

PSSMTCOL

Finds queries using a specified index, and shows the number of columns that match

PSSTBOIX

Finds queries accessing tables that have no indexes

PSSTSSCA

Finds queries performing table space scans on tables with CARD greater than a specified value

PSSUSEIX

Finds queries using a specified index


Note

The name of hlq.llqSAMP varies depending on your installation options and might be hlq.BMCSAMP.


Related topic

Sample-Explain-queries-for-history-tables

 

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