Creating adaptive server iq indexes, The create index statement – Sybase 12.4.2 User Manual

Page 158

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Creating Adaptive Server IQ indexes

138

Because indexes are compact, more data can be kept in memory for
subsequent queries, thereby speeding throughput on iterative analysis.

Tuning is data-dependent, allowing data to be optimized once for any
number of ad hoc queries.

Creating Adaptive Server IQ indexes

You can create a column index explicitly using either the

CREATE INDEX

statement or Sybase Central. These two methods are discussed in the sections
that follow.

The CREATE INDEX statement

To create an Adaptive Server IQ column index, use this syntax:

CREATE [ UNIQUE ] [

index-type ] INDEX index-name

... ON [

owner.]table-name

... (

column-name )

... [ { IN | ON }

dbspace-name ]

... [ NOTIFY

integer ]

If you do not specify an index-type, Adaptive Server IQ creates an

HG

index.

Several front-end tools create an

HG

index automatically for this reason.

Examples

The first example creates a High_Non_Group (

HNG

) index called

ship_ix

on

the

ship_date

column of the

sales_order_items

table.

CREATE HNG INDEX ship_ix

ON dbo.sales_order_items (ship_date)

The second example creates a Low_Fast index called

sales_order_region

on the

region

column of the

sales_order

table.

CREATE LF INDEX sales_order_region

ON dbo.sales_order (region)

By default, after every 100,000 records are inserted and loaded into indexes,
you receive a progress message. To change the number of records, specify the

NOTIFY

option of

CREATE INDEX

. To prevent these messages, specify

NOTIFY

0

.

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