Sybase 12.4.2 User Manual
CHAPTER 5 Moving Data In and Out of Databases
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For information on setting DBISQL database options, see “SET OPTION
statement” in the Adaptive Server IQ Reference Manual.
statement” in the Adaptive Server IQ Reference Manual.
Tuning bulk loading of data
Loading large volumes of data into a database can take a long time and use a
lot of disk space. There are a few things you can do to save time.
lot of disk space. There are a few things you can do to save time.
Improving load performance during database definition
The way you define your database, tables, and indexes can have a dramatic
impact on load performance.
impact on load performance.
Optimizing for the number of distinct values
Adaptive Server IQ optimizes loading of data for a large or small set of distinct
values, based on parameters you specify when you create your database and
tables. Parameters that affect load optimization include:
values, based on parameters you specify when you create your database and
tables. Parameters that affect load optimization include:
•
The
UNIQUE
and
IQ UNIQUE
options, and the data type and width of the
column, all specified in the
CREATE TABLE
or
ALTER TABLE
command.
•
The
IQ PAGE SIZE
, specified in the
CREATE DATABASE
command.
For details of how these parameters affect loading, and information on how to
specify them, see “Creating tables” and “Choosing an IQ page size”.
specify them, see “Creating tables” and “Choosing an IQ page size”.
Creating indexes
To make the best use of system resources, create all of the indexes you need
before loading data. While you can always add new indexes later, it is much
faster to load all indexes at once.
before loading data. While you can always add new indexes later, it is much
faster to load all indexes at once.