HI all,
I suppose there is only map function that will consume the heap memory assigned
to each map task. While the default heap memory is 200 mb, I just wonder most
of the memory is wasted for a simple map function (e.g. IdentityMapper).
So, I try to make use of this memory by buffering the output records, or
maintaining large data structure in memory, but it doesn't work as I expect.
For example, I want to build a hash table on a 100mb table in memory during the
life time of that map task. But it fails due to lack of heap memory. Don't I
get 200mb heap memory? What others also eat my heap memory?
Thanks.
-Gang
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