Rohini Palaniswamy created PIG-4963:
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Summary: Add a Bloom join
Key: PIG-4963
URL: https://issues.apache.org/jira/browse/PIG-4963
Project: Pig
Issue Type: New Feature
Reporter: Rohini Palaniswamy
In PIG-4925, added option to pass BloomFilter as a scalar to bloom function.
But found that actually using it for big data which required huge vector size
was very inefficient and led to OOM.
I had initially calculated that it would take around 12MB bytearray for 100
million vectorsize (100000000 + 7) / 8 = 12500000 bytes) and that would be the
scalar value broadcasted and would not take much space. But problem is 12MB was
written out for every input record with BuildBloom$Initial before the
aggregation happens and we arrive at the final BloomFilter vector. And with
POPartialAgg it runs into OOM issues.
If we added a bloom join implementation, which can be combined with hash or
skewed join it would boost performance for a lot of jobs. Bloom filter of the
smaller tables can be sent to the bigger tables as scalar and data filtered
before hash or skewed join is used.
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