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January 29, 2014

Memory Management in LoadRunner

Memory Management in LoadRunner

Many of you would’ve faced below errors during load testing using LoadRunner.

Action(24): Error -27977: Memory block size (65537) requested for value (<INPUT>) exceeds limit of 65535 bytes      [MsgId: MERR-27977]

Action(24): Error -27999: Not enough memory (65537 bytes) for a memory block for value (<INPUT>)      [MsgId: MERR-27999]

Assume that you are working on HTTP/HTML protocol and you faced above errors. In this blog post we will see about how to rectify above errors and memory management in LoadRunner.

For memory related errors, the culprit should be hiding in advance run-time settings. To access go to Vuser > Run-Time Settings > Internet Protocol > Preferences > Options.

Scroll down to Web (Click and Script) Specific > Memory Management as shown below.

Memory Management in LoadRunner

Memory Management in LoadRunner

There are four parameters available such as follows:

  • Default block size for DOM memory allocations.
  • Memory Manager for dynamically-created DOM objects
  • JavaScript Runtime memory size (KB)
  • JavaScript Stack memory size (KB)

Default block size for DOM memory allocations

By default you have 16384 block size for DOM memory allocations. If the value is too small then you might face extra calls to malloc which slows your execution. If the value is too big, it leads to larger footprint.

Memory Manager for dynamically-created DOM objects

If the choice is Yes then LoadRunner uses the memory manager for dynamically created DOM objects. If the choice is No, then it will not use. Use the protocol recommended choice.

JavaScript Runtime memory size (KB)

This value specified the JavaScript runtime memory size. Default value is 256 KB.

JavaScript Stack memory size (KB)

This value specified the JavaScript stack memory size. Default value is 32 KB.

For out of memory errors increase the JavaScript Runtime memory size (KB) and JavaScript Stack memory size (KB) values to 512 KB or higher.

If you are getting memory exceptions even after increasing the JavaScript size, then there is a possibility of your application having memory leaks.

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About NaveenKumar Namachivayam

Hi there! is a passionate and experienced Performance Test Analyst based in Chicago, USA with skill sets in Manual Testing, Test Automation, Performance Testing, and Test Estimation. He loves to learn and experiment new trends and models in Software Testing. Please stop by at his personal blogs: Excel Blog, DealsBrook, NaveenKumarN.in, and Affiliate Insights blog and Software Testing Memes.

One Comment on “Memory Management in LoadRunner

Sahil
May 20, 2014 at 8:35 pm

Hi Naveen,
I disagree with your this statement “If you are getting memory exceptions even after increasing the JavaScript size, then there is a possibility of your application having memory leaks”
The errors 27999 and 27977 clearly indicate that your load generator is having some issues or at the max your script.
Suggested solution: Reboot your Load Generator

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