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Tom Lane authored
SP-GiST is comparable to GiST in flexibility, but supports non-balanced partitioned search structures rather than balanced trees. As described at PGCon 2011, this new indexing structure can beat GiST in both index build time and query speed for search problems that it is well matched to. There are a number of areas that could still use improvement, but at this point the code seems committable. Teodor Sigaev and Oleg Bartunov, with considerable revisions by Tom Lane
Tom Lane authoredSP-GiST is comparable to GiST in flexibility, but supports non-balanced partitioned search structures rather than balanced trees. As described at PGCon 2011, this new indexing structure can beat GiST in both index build time and query speed for search problems that it is well matched to. There are a number of areas that could still use improvement, but at this point the code seems committable. Teodor Sigaev and Oleg Bartunov, with considerable revisions by Tom Lane
alter_opfamily.sgml 11.88 KiB
<!--
doc/src/sgml/ref/alter_opfamily.sgml
PostgreSQL documentation
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<refentry id="SQL-ALTEROPFAMILY">
<refmeta>
<refentrytitle>ALTER OPERATOR FAMILY</refentrytitle>
<manvolnum>7</manvolnum>
<refmiscinfo>SQL - Language Statements</refmiscinfo>
</refmeta>
<refnamediv>
<refname>ALTER OPERATOR FAMILY</refname>
<refpurpose>change the definition of an operator family</refpurpose>
</refnamediv>
<indexterm zone="sql-alteropfamily">
<primary>ALTER OPERATOR FAMILY</primary>
</indexterm>
<refsynopsisdiv>
<synopsis>
ALTER OPERATOR FAMILY <replaceable>name</replaceable> USING <replaceable class="parameter">index_method</replaceable> ADD
{ OPERATOR <replaceable class="parameter">strategy_number</replaceable> <replaceable class="parameter">operator_name</replaceable> ( <replaceable class="parameter">op_type</replaceable>, <replaceable class="parameter">op_type</replaceable> ) [ FOR SEARCH | FOR ORDER BY <replaceable class="parameter">sort_family_name</replaceable> ]
| FUNCTION <replaceable class="parameter">support_number</replaceable> [ ( <replaceable class="parameter">op_type</replaceable> [ , <replaceable class="parameter">op_type</replaceable> ] ) ] <replaceable class="parameter">function_name</replaceable> ( <replaceable class="parameter">argument_type</replaceable> [, ...] )
} [, ... ]
ALTER OPERATOR FAMILY <replaceable>name</replaceable> USING <replaceable class="parameter">index_method</replaceable> DROP
{ OPERATOR <replaceable class="parameter">strategy_number</replaceable> ( <replaceable class="parameter">op_type</replaceable> [ , <replaceable class="parameter">op_type</replaceable> ] )
| FUNCTION <replaceable class="parameter">support_number</replaceable> ( <replaceable class="parameter">op_type</replaceable> [ , <replaceable class="parameter">op_type</replaceable> ] )
} [, ... ]
ALTER OPERATOR FAMILY <replaceable>name</replaceable> USING <replaceable class="parameter">index_method</replaceable> RENAME TO <replaceable>new_name</replaceable>
ALTER OPERATOR FAMILY <replaceable>name</replaceable> USING <replaceable class="parameter">index_method</replaceable> OWNER TO <replaceable>new_owner</replaceable>
ALTER OPERATOR FAMILY <replaceable>name</replaceable> USING <replaceable class="parameter">index_method</replaceable> SET SCHEMA <replaceable>new_schema</replaceable>
</synopsis>
</refsynopsisdiv>
<refsect1>
<title>Description</title>
<para>
<command>ALTER OPERATOR FAMILY</command> changes the definition of
an operator family. You can add operators and support functions
to the family, remove them from the family,
or change the family's name or owner.
</para>
<para>
When operators and support functions are added to a family with
<command>ALTER OPERATOR FAMILY</command>, they are not part of any
specific operator class within the family, but are just <quote>loose</>
within the family. This indicates that these operators and functions
are compatible with the family's semantics, but are not required for
correct functioning of any specific index. (Operators and functions
that are so required should be declared as part of an operator class,
instead; see <xref linkend="sql-createopclass">.)
<productname>PostgreSQL</productname> will allow loose members of a
family to be dropped from the family at any time, but members of an
operator class cannot be dropped without dropping the whole class and
any indexes that depend on it.
Typically, single-data-type operators
and functions are part of operator classes because they are needed to
support an index on that specific data type, while cross-data-type
operators and functions are made loose members of the family.
</para>
<para>
You must be a superuser to use <command>ALTER OPERATOR FAMILY</>.
(This restriction is made because an erroneous operator family definition
could confuse or even crash the server.) </para>
<para>
<command>ALTER OPERATOR FAMILY</command> does not presently check
whether the operator family definition includes all the operators and
functions required by the index method, nor whether the operators and
functions form a self-consistent set. It is the user's
responsibility to define a valid operator family.
</para>
<para>
Refer to <xref linkend="xindex"> for further information.
</para>
</refsect1>
<refsect1>
<title>Parameters</title>
<variablelist>
<varlistentry>
<term><replaceable class="parameter">name</replaceable></term>
<listitem>
<para>
The name (optionally schema-qualified) of an existing operator
family.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><replaceable class="parameter">index_method</replaceable></term>
<listitem>
<para>
The name of the index method this operator family is for.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><replaceable class="parameter">strategy_number</replaceable></term>
<listitem>
<para>
The index method's strategy number for an operator
associated with the operator family.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><replaceable class="parameter">operator_name</replaceable></term>
<listitem>
<para>
The name (optionally schema-qualified) of an operator associated
with the operator family.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><replaceable class="parameter">op_type</replaceable></term>
<listitem>
<para>
In an <literal>OPERATOR</> clause,
the operand data type(s) of the operator, or <literal>NONE</> to
signify a left-unary or right-unary operator. Unlike the comparable
syntax in <command>CREATE OPERATOR CLASS</>, the operand data types
must always be specified.
</para>
<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 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 B-tree sort
support functions and all functions in GiST, SP-GiST and GIN operator
classes, it is necessary to specify the operand data type(s) the function
is to be used with.
</para>
<para>
In a <literal>DROP FUNCTION</> clause, the operand data type(s) the
function is intended to support must be specified.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><replaceable class="parameter">sort_family_name</replaceable></term>
<listitem>
<para>
The name (optionally schema-qualified) of an existing <literal>btree</literal> operator
family that describes the sort ordering associated with an ordering
operator.
</para>
<para>
If neither <literal>FOR SEARCH</> nor <literal>FOR ORDER BY</> is
specified, <literal>FOR SEARCH</> is the default.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><replaceable class="parameter">support_number</replaceable></term>
<listitem>
<para>
The index method's support procedure number for a
function associated with the operator family.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><replaceable class="parameter">function_name</replaceable></term>
<listitem>
<para>
The name (optionally schema-qualified) of a function that is an
index method support procedure for the operator family.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><replaceable class="parameter">argument_type</replaceable></term>
<listitem>
<para>
The parameter data type(s) of the function.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><replaceable class="parameter">new_name</replaceable></term>
<listitem>
<para>
The new name of the operator family.
</para>
</listitem> </varlistentry>
<varlistentry>
<term><replaceable class="parameter">new_owner</replaceable></term>
<listitem>
<para>
The new owner of the operator family.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term><replaceable class="parameter">new_schema</replaceable></term>
<listitem>
<para>
The new schema for the operator family.
</para>
</listitem>
</varlistentry>
</variablelist>
<para>
The <literal>OPERATOR</> and <literal>FUNCTION</>
clauses can appear in any order.
</para>
</refsect1>
<refsect1>
<title>Notes</title>
<para>
Notice that the <literal>DROP</> syntax only specifies the <quote>slot</>
in the operator family, by strategy or support number and input data
type(s). The name of the operator or function occupying the slot is not
mentioned. Also, for <literal>DROP FUNCTION</> the type(s) to specify
are the input data type(s) the function is intended to support; for
GiST, SP-GiST and GIN indexes this might have nothing to do with the actual
input argument types of the function.
</para>
<para>
Because the index machinery does not check access permissions on functions
before using them, including a function or operator in an operator family
is tantamount to granting public execute permission on it. This is usually
not an issue for the sorts of functions that are useful in an operator
family.
</para>
<para>
The operators should not be defined by SQL functions. A SQL function
is likely to be inlined into the calling query, which will prevent
the optimizer from recognizing that the query matches an index.
</para>
<para>
Before <productname>PostgreSQL</productname> 8.4, the <literal>OPERATOR</>
clause could include a <literal>RECHECK</> option. This is no longer
supported because whether an index operator is <quote>lossy</> is now
determined on-the-fly at run time. This allows efficient handling of
cases where an operator might or might not be lossy.
</para>
</refsect1>
<refsect1>
<title>Examples</title>
<para>
The following example command adds cross-data-type operators and
support functions to an operator family that already contains B-tree operator classes for data types <type>int4</> and <type>int2</>.
</para>
<programlisting>
ALTER OPERATOR FAMILY integer_ops USING btree ADD
-- int4 vs int2
OPERATOR 1 < (int4, int2) ,
OPERATOR 2 <= (int4, int2) ,
OPERATOR 3 = (int4, int2) ,
OPERATOR 4 >= (int4, int2) ,
OPERATOR 5 > (int4, int2) ,
FUNCTION 1 btint42cmp(int4, int2) ,
-- int2 vs int4
OPERATOR 1 < (int2, int4) ,
OPERATOR 2 <= (int2, int4) ,
OPERATOR 3 = (int2, int4) ,
OPERATOR 4 >= (int2, int4) ,
OPERATOR 5 > (int2, int4) ,
FUNCTION 1 btint24cmp(int2, int4) ;
</programlisting>
<para>
To remove these entries again:
</para>
<programlisting>
ALTER OPERATOR FAMILY integer_ops USING btree DROP
-- int4 vs int2
OPERATOR 1 (int4, int2) ,
OPERATOR 2 (int4, int2) ,
OPERATOR 3 (int4, int2) ,
OPERATOR 4 (int4, int2) ,
OPERATOR 5 (int4, int2) ,
FUNCTION 1 (int4, int2) ,
-- int2 vs int4
OPERATOR 1 (int2, int4) ,
OPERATOR 2 (int2, int4) ,
OPERATOR 3 (int2, int4) ,
OPERATOR 4 (int2, int4) ,
OPERATOR 5 (int2, int4) ,
FUNCTION 1 (int2, int4) ;
</programlisting>
</refsect1>
<refsect1>
<title>Compatibility</title>
<para>
There is no <command>ALTER OPERATOR FAMILY</command> statement in
the SQL standard.
</para>
</refsect1>
<refsect1>
<title>See Also</title>
<simplelist type="inline">
<member><xref linkend="sql-createopfamily"></member>
<member><xref linkend="sql-dropopfamily"></member>
<member><xref linkend="sql-createopclass"></member>
<member><xref linkend="sql-alteropclass"></member>
<member><xref linkend="sql-dropopclass"></member>
</simplelist>
</refsect1>
</refentry>