Initializing CLOB With Blank String Slows Down Performance When Connecting to 12c Database From 11g Client

(Doc ID 2361110.1)

Last updated on FEBRUARY 19, 2018

Applies to:

PL/SQL - Version 11.1.0.6 to 12.2.0.1 [Release 11.1 to 12.2]
Information in this document applies to any platform.

Symptoms

Running an anonymous PL/SQL block which declares a CLOB variable and initializes it with blank value inside a loop performs poorly when connecting to 12c database from 11g client.

For example when you run the below code connecting to a 12c database from a 11g client will run slowly when compared to using 12c client.

NOTE: The sample code is given just to demonstrate the timing issue. And the elapsed time can vary depending on the loop count as well as depending on the 11g client operating system. 

Changes

The database is upgraded to 12c or this is a new implementation.

Cause

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 hundreds of Community platforms