Roaring bitmap judgment functions

Roaring bitmap judgment functions perform judgment on the input Roaring bitmap data and return a Boolean value. OceanBase Database supports the rb_is_empty() and rb_contains() Roaring bitmap judgment functions.

rb_is_empty

rb_is_empty() judges whether the input Roaring bitmap data is empty. The syntax is as follows:

rb_is_empty(rb)

The returned value 1 indicates that the input bitmap data is empty, and 0 indicates that input bitmap data is not empty.

Here are some examples:

SELECT rb_is_empty(rb_from_string(''));
+---------------------------------+
| rb_is_empty(rb_from_string('')) |
+---------------------------------+
|                               1 |
+---------------------------------+
1 row in set

SELECT rb_is_empty(rb_from_string('1,2,3'));
+--------------------------------------+
| rb_is_empty(rb_from_string('1,2,3')) |
+--------------------------------------+
|                                    0 |
+--------------------------------------+
1 row in set

rb_contains

The rb_contains() function has two use cases:

• To check if the first input bitmap (rb1) fully contains the second input bitmap (rb2).
• To check if the input bitmap contains a specific offset (offset).

These two use cases are implemented using different syntax. Details are as follows:

Use case 1

The rb_contains() function can be used to determine whether the first input bitmap (rb1) fully contains the second input bitmap (rb2). The syntax is as follows:

rb_contains(rb1, rb2)

Specifically:

• The parameter rb1 serves as the base for the calculation, while rb2 is the bitmap being checked. The function determines whether every element in rb2 is also present in rb1.
• The order of the parameters rb1 and rb2 affects the result.
• The function returns 1 if rb1 fully contains rb2, and 0 if it does not.

Here is an example:

SELECT rb_contains(rb_from_string('1,2,3,4,5'), rb_from_string('1,2,3,4'));
+---------------------------------------------------------------------+
| rb_contains(rb_from_string('1,2,3,4,5'), rb_from_string('1,2,3,4')) |
+---------------------------------------------------------------------+
|                                                                   1 |
+---------------------------------------------------------------------+
1 row in set

Use case 2

The rb_contains() function can be used to determine whether the input bitmap data contains a specific offset (offset). The syntax is as follows:

rb_contains(rb, offset)

Specifically:

• The parameter rb serves as the basis for the calculation and is a bitmap dataset.
• offset must be an integer, used to check whether this integer exists in the bitmap data rb.
• The function returns 1 if the offset is contained within rb, and 0 if it is not.

Here is an example:

SELECT rb_contains(rb_from_string('1,2,3,4,5'), 1);
+---------------------------------------------+
| rb_contains(rb_from_string('1,2,3,4,5'), 1) |
+---------------------------------------------+
|                                           1 |
+---------------------------------------------+
1 row in set

SELECT rb_contains(rb_from_string('1,2,3,4,6'), 5);
+---------------------------------------------+
| rb_contains(rb_from_string('1,2,3,4,6'), 5) |
+---------------------------------------------+
|                                           0 |
+---------------------------------------------+
1 row in set