defined by the user for other data types using equivalent definitions,
without having to write any source code; appropriate catalog entries being
declared is enough. Note that assumptions about the semantics of operator
- strategies are embedded in the support procedures's source code.
+ strategies are embedded in the support procedures' source code.
|
Support Procedure 1
- function brin_minmax_opcinfo()
+ internal function brin_minmax_opcinfo()
|
Support Procedure 2
- function brin_minmax_add_value()
+ internal function brin_minmax_add_value()
|
Support Procedure 3
- function brin_minmax_consistent()
+ internal function brin_minmax_consistent()
|
Support Procedure 4
- function brin_minmax_union()
+ internal function brin_minmax_union()
|
Operator Strategy 1
+
+ To write an operator class for a complex datatype which has values
+ included within another type, it's possible to use the inclusion support
+ procedures alongside the corresponding operators, as shown
+ in . It requires
+ only a single additional function, which can be written in any language.
+ More functions can be defined for additional functionality. All operators
+ are optional. Some operators require other operators, as shown as
+ dependencies on the table.
+
+
+
Procedure and Support Numbers for Inclusion Operator Classes
+
+
+ |
+ Operator class member
+ Object
+ Dependency
+
+
+
+ |
+ Support Procedure 1
+ internal function brin_inclusion_opcinfo()
+
+
+ |
+ Support Procedure 2
+ internal function brin_inclusion_add_value()
+
+
+ |
+ Support Procedure 3
+ internal function brin_inclusion_consistent()
+
+
+ |
+ Support Procedure 4
+ internal function brin_inclusion_union()
+
+
+ |
+ Support Procedure 11
+ function to merge two elements
+
+
+ |
+ Support Procedure 12
+ optional function to check whether two elements are mergeable
+
+
+ |
+ Support Procedure 13
+ optional function to check if an element is contained within another
+
+
+ |
+ Support Procedure 14
+ optional function to check whether an element is empty
+
+
+ |
+ Operator Strategy 1
+ operator left-of
+ Operator Strategy 4
+
+ |
+ Operator Strategy 2
+ operator does-not-extend-to-the-right-of
+ Operator Strategy 5
+
+ |
+ Operator Strategy 3
+ operator overlaps
+
+
+ |
+ Operator Strategy 4
+ operator right-of
+ Operator Strategy 2
+
+ |
+ Operator Strategy 5
+ operator does-not-extend-to-the-right-of
+ Operator Strategy 1
+
+ |
+ Operator Strategy 6, 18
+ operator same-as-or-equal-to
+ Operator Strategy 7
+
+ |
+ Operator Strategy 7, 13, 16, 24, 25
+ operator contains-or-equal-to
+
+
+ |
+ Operator Strategy 8, 14, 26, 27
+ operator is-contained-by-or-equal-to
+ Operator Strategy 3
+
+ |
+ Operator Strategy 9
+ operator does-not-extend-above
+ Operator Strategy 11
+
+ |
+ Operator Strategy 10
+ operator is-below
+ Operator Strategy 12
+
+ |
+ Operator Strategy 11
+ operator is-above
+ Operator Strategy 9
+
+ |
+ Operator Strategy 12
+ operator does-not-extend-below
+ Operator Strategy 10
+
+ |
+ Operator Strategy 20
+ operator less-than
+ Operator Strategy 4
+
+ |
+ Operator Strategy 21
+ operator less-than-or-equal-to
+ Operator Strategy 4
+
+ |
+ Operator Strategy 22
+ operator greater-than
+ Operator Strategy 1
+
+ |
+ Operator Strategy 23
+ operator greater-than-or-equal-to
+ Operator Strategy 1
+
+
+
+
+
+ Support procedure numbers 1-10 are reserved for the BRIN internal
+ functions, so the SQL level functions start with number 11. Support
+ function number 11 is the main function required to build the index.
+ It should accept two arguments with the same datatype as the opclass,
+ and return the union of them. The inclusion opclass can store union
+ values with different datatypes if it is defined with the
+ STORAGE parameter. The return value of the union
+ function should match the STORAGE datatype.
+
+
+ Support procedure numbers 12 and 14 are provided to support
+ irregularities of built-in datatypes. Procedure number 12
+ is used to support network addresses from different families which
+ are not mergeable. Procedure number 14 is used to support
+ empty ranges. Procedure number 13 is an optional but
+ recommended one, which allows the new value to be checked before
+ it is passed to the union function. As the BRIN framework can shortcut
+ some operations when the union is not changed, using this
+ function can improve index performance.
+
+
+ Both minmax and inclusion opclasses support cross-datatype
+ operators, though with these the dependencies become more complicated.
+ The minmax opclass requires a full set of operators to be
+ defined with both arguments having the same datatype. It allows
+ additional datatypes to be supported by defining extra sets
+ of operators. Inclusion opclass operator strategies are dependent
+ on another operator strategy as shown in
+ , or the same
+ operator strategy as themselves. They require the dependency
+ operator to be defined with the STORAGE datatype as the
+ left-hand-side argument and the other supported datatype to be the
+ right-hand-side argument of the supported operator. See
+ float4_minmax_ops as an example of minmax, and
+ box_inclusion_ops as an example of inclusion.
+
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