I have read the docs about taskqueue and push queues in gae which is used to create long running tasks.
I have doubt in why there was the need for MapReduce? As both do the processing in background, what are the main principal differences between them.
Can someone please explain this?
Edit: I guess i was comparing Apples with monkeys! Hadoop, mapreduce are related. And gae is a backend framework.
You are getting confused with two entirely different things altogether.
MapReduce paradigm is all about distributed parallel processing of very huge amount of data.
TaskQueue is a Scheduler; which can schedule a task to execute say at certain time. It is just a scheduler like a unix cronjobs.
Please take note of bold and italic words in above statements to see the difference.
From the definition of TaskQueue
Task queues let applications perform work, called tasks, asynchronously outside of a user request. If an app needs to execute work in the background, it adds tasks to task queues. The tasks are executed later, by worker services.
By definition, TaskQueue work outside of a user request; means there is no actual user request to perform a task (it is simply submitted/scheduled sometime in past). mapreduce programs are submitted by users to execute, though you may use TaskQueue to schedule one in future.
You are probably getting confused due to words like task, queue, scheduling used in mapreduce world. But those all thing in mapreduce may have some similarity, as they are generic terms - but they are definitely not the same.
