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Create a "sort support" interface API for faster sorting.

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This patch creates an API whereby a btree index opclass can optionally
provide non-SQL-callable support functions for sorting.  In the initial
patch, we only use this to provide a directly-callable comparator function,
which can be invoked with a bit less overhead than the traditional
SQL-callable comparator.  While that should be of value in itself, the real
reason for doing this is to provide a datatype-extensible framework for
more aggressive optimizations, as in Peter Geoghegan's recent work.

Robert Haas and Tom Lane
This commit is contained in:
Tom Lane
2011-12-07 00:18:38 -05:00
parent d2a662182e
commit c6e3ac11b6
30 changed files with 869 additions and 421 deletions
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9
doc/src/sgml/ref/alter_opfamily.sgml
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@@ -140,11 +140,12 @@ ALTER OPERATOR FAMILY <replaceable>name</replaceable> USING <replaceable class="
<para>
In an <literal>ADD FUNCTION</> clause, the operand data type(s) the
function is intended to support, if different from
the input data type(s) of the function. For B-tree and hash indexes
it is not necessary to specify <replaceable
the input data type(s) of the function. For B-tree comparison functions
and hash functions it is not necessary to specify <replaceable
class="parameter">op_type</replaceable> since the function's input
data type(s) are always the correct ones to use. For GIN and GiST
indexes it is necessary to specify the input data type the function
data type(s) are always the correct ones to use. For B-tree sort
support functions and all functions in GiST and GIN operator classes,
it is necessary to specify the operand data type(s) the function
is to be used with.
</para>

15
doc/src/sgml/ref/create_opclass.sgml
View File

@@ -169,13 +169,14 @@ CREATE OPERATOR CLASS <replaceable class="parameter">name</replaceable> [ DEFAUL
<para>
In a <literal>FUNCTION</> clause, the operand data type(s) the
function is intended to support, if different from
the input data type(s) of the function (for B-tree and hash indexes)
or the class's data type (for GIN and GiST indexes). These defaults
are always correct, so there is no point in specifying <replaceable
class="parameter">op_type</replaceable> in a <literal>FUNCTION</> clause
in <command>CREATE OPERATOR CLASS</>, but the option is provided
for consistency with the comparable syntax in
<command>ALTER OPERATOR FAMILY</>.
the input data type(s) of the function (for B-tree comparison functions
and hash functions)
or the class's data type (for B-tree sort support functions and all
functions in GiST and GIN operator classes). These defaults
are correct, and so <replaceable
class="parameter">op_type</replaceable> need not be specified in
<literal>FUNCTION</> clauses, except for the case of a B-tree sort
support function that is meant to support cross-data-type comparisons.
</para>
</listitem>
</varlistentry>