My Oracle Support Banner

Determining if SQL Apply Engine is Performing Full Table Scans (Doc ID 255958.1)

Last updated on DECEMBER 28, 2023

Applies to:

Oracle Database Backup Service - Version N/A and later
Oracle Database Cloud Exadata Service - Version N/A and later
Oracle Database Exadata Express Cloud Service - Version N/A and later
Oracle Database Cloud Service - Version N/A and later
Oracle Database - Enterprise Edition - Version 9.0.1.0 to 11.2.0.2 [Release 9.0.1 to 11.2]
Information in this document applies to any platform.

Purpose

One of the primary reasons for the logical apply engine to slow is due to full
table scans. For example, one delete, insert, or update statement on the primary
that modifies 1000 rows will become 1000 individual statements on the logical
standby. If we incur a full table scan applying that change to the standby
then performance can be significantly impacted.

The following procedure will provide a method to determine if the apply engine
is performing full table scans.

NOTE: In the images and/or the document content below, the user information and environment data used
represents fictitious data from the Oracle sample schema(s), Public Documentation delivered with an Oracle
database product or other training material. Any similarity to actual environments, actual persons, living
or dead, is purely coincidental and not intended in any manner.

For the purposes of this document, the following fictitious environment is used as an example to describe the procedure:

Oracle_SID: ls920

 

Troubleshooting Steps

To view full details, sign in with your My Oracle Support account.

Don't have a My Oracle Support account? Click to get started!

My Oracle Support provides customers with access to over a million knowledge articles and a vibrant support community of peers and Oracle experts.