WebLogic Stuck Thread Case – Large Fetch Generated by get row ADF BC method by Red Samurai

Posted: January 16, 2014 in Uncategorized
Tags: , , , , , ,

This post is not about a bug, but rather about hidden underwater stone to avoid. Based on my previous use case for WebLogic Stuck Thread – Reproducing WebLogic Stuck Threads with ADF CreateInsert Operation and ORDER BY Clause, I will describe one more possible scenario for the same issue. This will be related to ADF BC API misuse, often it is unclear what side effect could produce at first friendly looking method. This method – getRow(key).
Please download complete sample application, if you are interested to reproduce it in your environment -  LargeFetchApp_v3.zip.
This sample provides a method to generate dummy data for regions, around 10000 rows. View Object is using ORDER BY to display records in ascending order:

There is custom method created in AM implementation class. This method is calling ADF BC API getRow(key) method. Nothing dangerous at first, but here I’m using a key of the last record from the rowset – 10099. You may think, this is just a method to get a row by key.

Yes true, but what it does for you – before returning one row by key, it will fetch all rows until this row into memory. It travels through each row one by one, until it gets a row with defined key. This may consume a lot of memory, especially if rowset is large and row with defined key is somewhere at the end of the rowset. Example of such method. Read the complete article here.

WebLogic Partner Community

For regular information become a member in the WebLogic Partner Community please visit: http://www.oracle.com/partners/goto/wls-emea ( OPN account required). If you need support with your account please contact the Oracle Partner Business Center.

Blog Twitter LinkedIn Mix Forum Wiki

Advertisements

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

w

Connecting to %s