Github user xuchuanyin commented on a diff in the pull request:
https://github.com/apache/carbondata/pull/2567#discussion_r206462541
--- 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 --
Added example
```
In one test scenario, a 96GB TPCH consumer table with bloom_size=320000 and
bloom_fpp=0.00001 will result in 18 false positive samples
```
---
