Bitmap Functions
Since 8.1.3, GaussDB(DWS) supports efficient bitmap processing functions and operators, which can be used in user profiling and precision marketing, greatly improving query performance.
rb_build(array)
Description: Converts an int array to the RoaringBitmap type.
Return type: RoaringBitmap
Example:
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SELECT rb_build('{1,2,3}'); rb_build ------------------------------------------------ \x3a300000010000000000020010000000010002000300 (1 row) |
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create table r_row (a int, b text, c roaringbitmap); NOTICE: The 'DISTRIBUTE BY' clause is not specified. Using round-robin as the distribution mode by default. HINT: Please use 'DISTRIBUTE BY' clause to specify suitable data distribution column. CREATE TABLE insert into r_row values (1, 'a', rb_build('{1,2,3}')); INSERT 0 1 SELECT * from r_row; a | b | c ---+---+------------------------------------------------ 1 | a | \x3a300000010000000000020010000000010002000300 (1 row) |
rb_iterate(roaringbitmap)
Description: Converts roaringbitmap data into int data and outputs the data in multiple lines.
Return type: record (int value in multiple rows)
Example:
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SELECT rb_iterate(c) FROM r_row; rb_iterate ------------ 1 2 3 (3 rows) |
rb_to_array(roaringbitmap)
Description: Using rb_build reverse operation to convert roaringBitmap into an int array.
Return type: array
Example:
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SELECT rb_to_array(c) FROM r_row; rb_to_array ------------- {1,2,3} (1 row) SELECT rb_to_array('\x3a300000010000000000020010000000010002000300'); rb_to_array ------------- {1,2,3} (1 row) |
rb_and(roaringbitmap, roaringbitmap)
Description: Calculates the intersection of two Roaring bitmaps.
Return type: RoaringBitmap
Example:
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SELECT rb_to_array(rb_and(rb_build('{1,2,3}'), rb_build('{2,3,4}'))); rb_to_array ------------- {2,3} (1 row) |
rb_or(roaringbitmap, roaringbitmap)
Description: Calculates the union of two Roaring bitmaps.
Return type: RoaringBitmap
Example:
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SELECT rb_to_array(rb_or(rb_build('{1,2,3}'), rb_build('{2,3,4}'))); rb_to_array ------------- {1,2,3,4} (1 row) |
rb_xor(roaringbitmap, roaringbitmap)
Description: Calculates the XOR of two Roaring bitmaps.
Return type: RoaringBitmap
Example:
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SELECT rb_to_array(rb_xor(rb_build('{1,2,3}'), rb_build('{2,3,4}'))); rb_to_array ------------- {1,4} (1 row) |
rb_andnot(roaringbitmap, roaringbitmap)
Description: Sets in the first Roaring bitmap set but not in the second Roaring bitmap set.
Return type: RoaringBitmap
Example:
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SELECT rb_to_array(rb_andnot(rb_build('{1,2,3}'), rb_build('{2,3,4}'))); rb_to_array ------------- {1} (1 row) |
rb_cardinality(roaringbitmap)
Description: Calculates the cardinality of a Roaring bitmap.
Return type: int
Example:
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SELECT rb_cardinality(rb_build('{1,2,3}')); rb_cardinality ---------------- 3 (1 row) |
rb_and_cardinality(roaringbitmap, roaringbitmap)
Description: Calculates the cardinality of the intersection of two Roaring bitmaps.
Return type: int
Example:
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SELECT rb_and_cardinality(rb_build('{1,2,3}'), rb_build('{2,3,4}')); rb_and_cardinality -------------------- 2 (1 row) |
rb_or_cardinality(roaringbitmap, roaringbitmap)
Description: Calculates the cardinality of the union of two Roaring bitmaps.
Return type: int
Example:
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SELECT rb_or_cardinality(rb_build('{1,2,3}'), rb_build('{2,3,4}')); rb_or_cardinality ------------------- 4 (1 row) |
rb_xor_cardinality(roaringbitmap, roaringbitmap)
Description: Calculates the cardinality of two Roaring bitmaps after the XOR operation.
Return type: int
Example:
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SELECT rb_xor_cardinality(rb_build('{1,2,3}'), rb_build('{2,3,4}')); rb_xor_cardinality -------------------- 2 (1 row) |
rb_andnot_cardinality(roaringbitmap, roaringbitmap)
Description: Calculates the cardinality of two Roaring bitmaps after ANDNOT operation.
Return type: int
Example:
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SELECT rb_andnot_cardinality(rb_build('{1,2,3}'), rb_build('{2,3,4}')); rb_andnot_cardinality ----------------------- 1 (1 row) |
rb_is_empty(roaringbitmap)
Description: Determines whether a Roaring bitmap is empty.
Return type: bool
Example:
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SELECT rb_is_empty(rb_build('{1,2,3}')); rb_is_empty ------------- f (1 row) |
rb_equals(roaringbitmap, roaringbitmap)
Description: Determines whether two Roaring bitmaps are equal.
Return type: bool
Example:
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SELECT rb_equals(rb_build('{1,2,3}'), rb_build('{2,3,4}')); rb_equals ----------- f (1 row) |
rb_intersect(roaringbitmap, roaringbitmap)
Description: Determines whether two Roaring bitmaps are intersected.
Return type: bool
Example:
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SELECT rb_intersect(rb_build('{1,2,3}'), rb_build('{2,3,4}')); rb_intersect -------------- t (1 row) |
rb_min(roaringbitmap)
Description: Returns the minimum value in a Roaring bitmap.
Return type: int
Example:
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SELECT rb_min(rb_build('{1,2,3}')); rb_min -------- 1 (1 row) |
rb_max(roaringbitmap)
Description: Returns the maximum value in a Roaring bitmap.
Return type: int
Example:
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SELECT rb_max(rb_build('{1,2,3}')); rb_max -------- 3 (1 row) |
rb_add(roaringbitmap, int)
Description: Adds an element to a Roaring bitmap.
Return type: RoaringBitmap
Example:
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SELECT rb_to_array(rb_add(rb_build('{1,3}'), 2)); rb_to_array ------------- {1,2,3} (1 row) |
rb_added(int, roaringbitmap)
Description: Adds an element to a Roaring bitmap.
Return type: RoaringBitmap
Example:
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SELECT rb_to_array(rb_added(2, rb_build('{1,3}'))); rb_to_array ------------- {1,2,3} (1 row) |
rb_contain(roaringbitmap,int)
Description: Determines whether a Roaring bitmap contains the specified element.
Return type: bool
Example:
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SELECT rb_contain(rb_build('{1,3}'), 2); rb_contain ------------ f (1 row) |
rb_containedby(int,roaringbitmap)
Description: Determines whether the given element is included in a given Roaring bitmap.
Example:
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SELECT rb_containedby(2,rb_build('{1,3}')); rb_containedby ---------------- f (1 row) |
rb_contain_rb(roaringbitmap,roaringbitmap)
Description: Determines whether the first Roaring bitmap contains the second Roaring bitmap.
Return type: bool
Example:
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SELECT rb_contain_rb(rb_build('{1,3}'), rb_build('{2,3}')); rb_contain_rb --------------- f (1 row) |
rb_containedby_rb(roaringbitmap,roaringbitmap)
Description: Determines whether the second Roaring bitmap contains the first Roaring bitmap.
Return type: bool
Example:
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SELECT rb_containedby_rb(rb_build('{1,3}'), rb_build('{2,3}')); rb_contain_rb --------------- f (1 row) |
rb_remove(roaringbitmap,int)
Description: Removes elements from a Roaring bitmap.
Return type: RoaringBitmap
Example:
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SELECT rb_to_array(rb_remove(rb_build('{1,3}'),1)); rb_to_array ------------- {3} (1 row) |
rb_flip(roaringbitmap,int,int)
Description: Reverses elements in a specified range.
Example:
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SELECT rb_to_array(rb_flip(rb_build('{1,2,3,7,9}'), 1,10)); rb_to_array -------------- {4,5,6,8,10} (1 row) |
rb_rank(roaringbitmap,int)
Description: Returns the cardinality of the set of values less than the specified value.
Return type: int
Example:
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SELECT rb_rank(rb_build('{1,10,100}'),99); rb_rank --------- 2 (1 row) |
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