Support bitmap_intersect #3571
Support bitmap_intersect #3571
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Support aggregate function Bitmap Intersect, it is mainly used to take intersection of grouped data.
The function 'bitmap_intersect(expr)' calculates the intersection of bitmap columns and returns a bitmap object.
The defination is following:
FunctionName: bitmap_intersect,
InputType: bitmap,
OutputType: bitmap
The scenario is as follows:
Query which users satisfy the three tags a, b, and c at the same time.
```
select bitmap_to_string(bitmap_intersect(user_id)) from
(
select bitmap_union(user_id) user_id from bitmap_intersect_test
where tag in ('a', 'b', 'c')
group by tag
) a
```
Closed apache#3552.
Change-Id: I0d50c9bb6827f7319c4d854f621412343a3ece24
EmmyMiao87
added
kind/feature
|
I will add sql-reference later. |
Co-authored-by: Mingyu Chen <morningman.cmy@gmail.com>
Change-Id: I4a815eaa5aac07ab75bb07e13f518da59cbef952
…bator-doris into bitmap_intersect Change-Id: I2f5bee7dd9a14f687881af8038dbbff17b6b6590
Change-Id: Ibb9bdb236d4d850e3d732bb55c441b7f8b80abba
Change-Id: I8bd03f5344eafc89a7d617d10399c848006bf590
| return; | ||
| } | ||
| // if dst is null, the src input is the first value | ||
| if (dst->is_null) { |
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Would better add a UNLIKELY macros.
docs/en/sql-reference/sql-functions/bitmap-functions/bitmap_intersect.md
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| // this is the read init function for bitmap_intersect | ||
| void BitmapFunctions::bitmap_intersect_init_real(FunctionContext* ctx, StringVal* dst) { | ||
| dst->is_null = true; |
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why initial result bitmap as null? it seems that it will return empty bitmap when result bitmap is null
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The initial result bitmap must be null. Otherwise, the intersection between dst and src will be empty.
|
@EmmyMiao87 Hi. 按照SQL标准，sum(null), min(null), max(null)结果为 null. count(null)为0. 所以 对于 bitmap_intersect，bitmap_union 返回bitmap的函数，输入全是null时，应该返回null, 在之前最开始的时候，我认为所有hll,bitmap的函数都不需要返回null，对于输入是null，我们返回empty bitmap 或者empty hll 即可。（it's my fault...） 所以目前bitmap_init, bitmap_serialize, bitmap_finalize的实现都是not nullable的。 |
Change-Id: I2d86d48dd5f5e836696b3d44620de41943052ee6
Change-Id: Ic21f0d500f464cee5d51e54858a18c89d080631b
|
LGTM, +1 |
…fig disable auto start (apache#3571)
6 participants
Support aggregate function Bitmap Intersect, it is mainly used to take intersection of grouped data.
The function 'bitmap_intersect(expr)' calculates the intersection of bitmap columns and returns a bitmap object.
The defination is following:
FunctionName: bitmap_intersect,
InputType: bitmap,
OutputType: bitmap
The scenario is as follows:
Query which users satisfy the three tags a, b, and c at the same time.
Closed #3552.
Change-Id: I0d50c9bb6827f7319c4d854f621412343a3ece24