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How Application Performance get impacted by Garbage Collection?

As we seen in our earlier posts that garbage collection is fully dependent on number of objects alive. Because according to mark and sweep algorithm first it will mark all the alive object and then it will remove all other from memory. Means if heap is completely filled with dead objects it will take fraction of second to complete GC cycle. Garbage collector must suspend the execution of the application to ensure the integrity of the object trees.

 So if we have more live objects it will take more time for GC and the suspension time will increase. Which will give a direct impact on response time and throughput. And will slow your application. This suspension off application threads to run the garbage collector is called garbage-collection pause or GC pause time. An application that spends 1% of its execution time on garbage collection will loose more than 20% throughput on a 32-processor system. If we increase the GC time to 2%, the overall throughput will drop by another 20%.




So a long GC Pause can have a direct impact on response time and throughput.So Now this becomes important to check all long GC pause to make application quick and decrease its response time . This can be done by checking all the possible case of long gc and try to eliminate them . To learn more about Causes of Long GC pause check


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4 mains causes of Long Garbage Collection Pause?

So a long GC Pause can have a direct impact on response time and throughput. But there are some causes for long GC pause which you can check and avoid to increase performance. They are as follows:-


1)Insufficient heap size:- If heap size is small then the size required then the allocation requests for new objects  fail and the JVM needs to invoke garbage collections in an attempt to reclaim space for the allocations. So these frequent Full GCs cause long pauses in the application run. To avoid long GC pause by this identify the average footprint of the application and then specify the heap size accordingly.
2)Fragmentation in the heap:-GCs can occur more frequently due to fragmentation in the Java Heap  and also sometimes causing long pauses in the GCs. This is more probable in the case of Concurrent Mark Sweep collector, also known as CMS, where the tenured generation space is not compacted with the concurrent collections. For more please go through the previous post about heap  compact…