Github user jackylk commented on a diff in the pull request:
https://github.com/apache/carbondata/pull/2567#discussion_r206417322
--- Diff: docs/datamap/bloomfilter-datamap-guide.md ---
@@ -83,8 +83,8 @@ User can create BloomFilter datamap using the Create
DataMap DDL:
| Property | Is Required | Default Value | Description |
|-------------|----------|--------|---------|
| INDEX_COLUMNS | YES | | Carbondata will generate BloomFilter index on
these columns. Queries on there columns are usually like 'COL = VAL'. |
-| BLOOM_SIZE | NO | 32000 | This value is internally used by BloomFilter
as the number of expected insertions, it will affects the size of BloomFilter
index. Since each blocklet has a BloomFilter here, so the value is the
approximate records in a blocklet. In another word, the value 32000 *
#noOfPagesInBlocklet. The value should be an integer. |
-| BLOOM_FPP | NO | 0.01 | This value is internally used by BloomFilter as
the False-Positive Probability, it will affects the size of bloomfilter index
as well as the number of hash functions for the BloomFilter. The value should
be in range (0, 1). |
+| BLOOM_SIZE | NO | 640000 | This value is internally used by BloomFilter
as the number of expected insertions, it will affects the size of BloomFilter
index. Since each blocklet has a BloomFilter here, so the value is the
approximate records in a blocklet. In another word, the value 32000 *
#noOfPagesInBlocklet. The value should be an integer. |
+| BLOOM_FPP | NO | 0.00001 | This value is internally used by BloomFilter
as the False-Positive Probability, it will affects the size of bloomfilter
index as well as the number of hash functions for the BloomFilter. The value
should be in range (0, 1). |
--- End diff --
explain `the default value is set to 0.00001 to make low false-positive
while keep bloomfilter in acceptable size`. Or can you provide some data for
the size?
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