Skip to content

P
Postgres FD Implementation
Commit 752b948d authored by Robert Haas's avatar Robert Haas
Browse files
Options

Document which aggregates support partial mode. 

David Rowley, reviewed by Tomas Vondra
parent 5c3c3cd0
Hide whitespace changes
Inline Side-by-side
Showing with 60 additions and 4 deletions
doc/src/sgml/func.sgml
View file @ 752b948d
......@@ -12678,12 +12678,13 @@ NULL baz</literallayout>(3 rows)</entry>
<table id="functions-aggregate-table">
<title>General-Purpose Aggregate Functions</title>
<tgroup cols="4">
<tgroup cols="5">
<thead>
<row>
<entry>Function</entry>
<entry>Argument Type(s)</entry>
<entry>Return Type</entry>
<entry>Partial Mode</entry>
<entry>Description</entry>
</row>
</thead>
......@@ -12702,6 +12703,7 @@ NULL baz</literallayout>(3 rows)</entry>
<entry>
array of the argument type
</entry>
<entry>No</entry>
<entry>input values, including nulls, concatenated into an array</entry>
</row>
......@@ -12715,6 +12717,7 @@ NULL baz</literallayout>(3 rows)</entry>
<entry>
same as argument data type
</entry>
<entry>No</entry>
<entry>input arrays concatenated into array of one higher dimension
(inputs must all have same dimensionality,
and cannot be empty or NULL)</entry>
......@@ -12740,6 +12743,7 @@ NULL baz</literallayout>(3 rows)</entry>
<type>double precision</type> for a floating-point argument,
otherwise the same as the argument data type
</entry>
<entry>All types apart from floating-point types</entry>
<entry>the average (arithmetic mean) of all input values</entry>
</row>
......@@ -12757,6 +12761,7 @@ NULL baz</literallayout>(3 rows)</entry>
<entry>
same as argument data type
</entry>
<entry>Yes</entry>
<entry>the bitwise AND of all non-null input values, or null if none</entry>
</row>
......@@ -12774,6 +12779,7 @@ NULL baz</literallayout>(3 rows)</entry>
<entry>
same as argument data type
</entry>
<entry>Yes</entry>
<entry>the bitwise OR of all non-null input values, or null if none</entry>
</row>
......@@ -12790,6 +12796,7 @@ NULL baz</literallayout>(3 rows)</entry>
<entry>
<type>bool</type>
</entry>
<entry>Yes</entry>
<entry>true if all input values are true, otherwise false</entry>
</row>
......@@ -12806,6 +12813,7 @@ NULL baz</literallayout>(3 rows)</entry>
<entry>
<type>bool</type>
</entry>
<entry>Yes</entry>
<entry>true if at least one input value is true, otherwise false</entry>
</row>
......@@ -12818,6 +12826,7 @@ NULL baz</literallayout>(3 rows)</entry>
</entry>
<entry></entry>
<entry><type>bigint</type></entry>
<entry>Yes</entry>
<entry>number of input rows</entry>
</row>
......@@ -12825,6 +12834,7 @@ NULL baz</literallayout>(3 rows)</entry>
<entry><function>count(<replaceable class="parameter">expression</replaceable>)</function></entry>
<entry>any</entry>
<entry><type>bigint</type></entry>
<entry>Yes</entry>
<entry>
number of input rows for which the value of <replaceable
class="parameter">expression</replaceable> is not null
......@@ -12844,6 +12854,7 @@ NULL baz</literallayout>(3 rows)</entry>
<entry>
<type>bool</type>
</entry>
<entry>Yes</entry>
<entry>equivalent to <function>bool_and</function></entry>
</row>
......@@ -12860,6 +12871,7 @@ NULL baz</literallayout>(3 rows)</entry>
<entry>
<type>json</type>
</entry>
<entry>No</entry>
<entry>aggregates values as a JSON array</entry>
</row>
......@@ -12876,6 +12888,7 @@ NULL baz</literallayout>(3 rows)</entry>
<entry>
<type>jsonb</type>
</entry>
<entry>No</entry>
<entry>aggregates values as a JSON array</entry>
</row>
......@@ -12892,6 +12905,7 @@ NULL baz</literallayout>(3 rows)</entry>
<entry>
<type>json</type>
</entry>
<entry>No</entry>
<entry>aggregates name/value pairs as a JSON object</entry>
</row>
......@@ -12908,6 +12922,7 @@ NULL baz</literallayout>(3 rows)</entry>
<entry>
<type>jsonb</type>
</entry>
<entry>No</entry>
<entry>aggregates name/value pairs as a JSON object</entry>
</row>
......@@ -12921,6 +12936,7 @@ NULL baz</literallayout>(3 rows)</entry>
<entry>any numeric, string, date/time, network, or enum type,
or arrays of these types</entry>
<entry>same as argument type</entry>
<entry>Yes</entry>
<entry>
maximum value of <replaceable
class="parameter">expression</replaceable> across all input
......@@ -12938,6 +12954,7 @@ NULL baz</literallayout>(3 rows)</entry>
<entry>any numeric, string, date/time, network, or enum type,
or arrays of these types</entry>
<entry>same as argument type</entry>
<entry>Yes</entry>
<entry>
minimum value of <replaceable
class="parameter">expression</replaceable> across all input
......@@ -12961,6 +12978,7 @@ NULL baz</literallayout>(3 rows)</entry>
<entry>
same as argument types
</entry>
<entry>No</entry>
<entry>input values concatenated into a string, separated by delimiter</entry>
</row>
......@@ -12983,6 +13001,7 @@ NULL baz</literallayout>(3 rows)</entry>
<type>bigint</type> arguments, otherwise the same as the
argument data type
</entry>
<entry>All types apart from floating-point types</entry>
<entry>sum of <replaceable class="parameter">expression</replaceable> across all input values</entry>
</row>
......@@ -12999,6 +13018,7 @@ NULL baz</literallayout>(3 rows)</entry>
<entry>
<type>xml</type>
</entry>
<entry>No</entry>
<entry>concatenation of XML values (see also <xref linkend="functions-xml-xmlagg">)</entry>
</row>
</tbody>
......@@ -13015,6 +13035,12 @@ NULL baz</literallayout>(3 rows)</entry>
substitute zero or an empty array for null when necessary.
</para>
<para>
Aggregate functions which support <firstterm>Partial Mode</firstterm>
are eligible to participate in various optimizations, such as parallel
aggregation.
</para>
<note>
<indexterm>
<primary>ANY</primary>
......@@ -13098,12 +13124,13 @@ SELECT xmlagg(x) FROM (SELECT x FROM test ORDER BY y DESC) AS tab;
<table id="functions-aggregate-statistics-table">
<title>Aggregate Functions for Statistics</title>
<tgroup cols="4">
<tgroup cols="5">
<thead>
<row>
<entry>Function</entry>
<entry>Argument Type</entry>
<entry>Return Type</entry>
<entry>Partial Mode</entry>
<entry>Description</entry>
</row>
</thead>
......@@ -13126,6 +13153,7 @@ SELECT xmlagg(x) FROM (SELECT x FROM test ORDER BY y DESC) AS tab;
<entry>
<type>double precision</type>
</entry>
<entry>No</entry>
<entry>correlation coefficient</entry>
</row>
......@@ -13146,6 +13174,7 @@ SELECT xmlagg(x) FROM (SELECT x FROM test ORDER BY y DESC) AS tab;
<entry>
<type>double precision</type>
</entry>
<entry>No</entry>
<entry>population covariance</entry>
</row>
......@@ -13166,6 +13195,7 @@ SELECT xmlagg(x) FROM (SELECT x FROM test ORDER BY y DESC) AS tab;
<entry>
<type>double precision</type>
</entry>
<entry>No</entry>
<entry>sample covariance</entry>
</row>
......@@ -13182,6 +13212,7 @@ SELECT xmlagg(x) FROM (SELECT x FROM test ORDER BY y DESC) AS tab;
<entry>
<type>double precision</type>
</entry>
<entry>No</entry>
<entry>average of the independent variable
(<literal>sum(<replaceable class="parameter">X</replaceable>)/<replaceable class="parameter">N</replaceable></literal>)</entry>
</row>
......@@ -13199,6 +13230,7 @@ SELECT xmlagg(x) FROM (SELECT x FROM test ORDER BY y DESC) AS tab;
<entry>
<type>double precision</type>
</entry>
<entry>No</entry>
<entry>average of the dependent variable
(<literal>sum(<replaceable class="parameter">Y</replaceable>)/<replaceable class="parameter">N</replaceable></literal>)</entry>
</row>
......@@ -13216,6 +13248,7 @@ SELECT xmlagg(x) FROM (SELECT x FROM test ORDER BY y DESC) AS tab;
<entry>
<type>bigint</type>
</entry>
<entry>No</entry>
<entry>number of input rows in which both expressions are nonnull</entry>
</row>
......@@ -13235,6 +13268,7 @@ SELECT xmlagg(x) FROM (SELECT x FROM test ORDER BY y DESC) AS tab;
<entry>
<type>double precision</type>
</entry>
<entry>No</entry>
<entry>y-intercept of the least-squares-fit linear equation
determined by the (<replaceable
class="parameter">X</replaceable>, <replaceable
......@@ -13254,6 +13288,7 @@ SELECT xmlagg(x) FROM (SELECT x FROM test ORDER BY y DESC) AS tab;
<entry>
<type>double precision</type>
</entry>
<entry>No</entry>
<entry>square of the correlation coefficient</entry>
</row>
......@@ -13273,6 +13308,7 @@ SELECT xmlagg(x) FROM (SELECT x FROM test ORDER BY y DESC) AS tab;
<entry>
<type>double precision</type>
</entry>
<entry>No</entry>
<entry>slope of the least-squares-fit linear equation determined
by the (<replaceable class="parameter">X</replaceable>,
<replaceable class="parameter">Y</replaceable>) pairs</entry>
......@@ -13291,6 +13327,7 @@ SELECT xmlagg(x) FROM (SELECT x FROM test ORDER BY y DESC) AS tab;
<entry>
<type>double precision</type>
</entry>
<entry>No</entry>
<entry><literal>sum(<replaceable
class="parameter">X</replaceable>^2) - sum(<replaceable
class="parameter">X</replaceable>)^2/<replaceable
......@@ -13311,6 +13348,7 @@ SELECT xmlagg(x) FROM (SELECT x FROM test ORDER BY y DESC) AS tab;
<entry>
<type>double precision</type>
</entry>
<entry>No</entry>
<entry><literal>sum(<replaceable
class="parameter">X</replaceable>*<replaceable
class="parameter">Y</replaceable>) - sum(<replaceable
......@@ -13334,6 +13372,7 @@ SELECT xmlagg(x) FROM (SELECT x FROM test ORDER BY y DESC) AS tab;
<entry>
<type>double precision</type>
</entry>
<entry>No</entry>
<entry><literal>sum(<replaceable
class="parameter">Y</replaceable>^2) - sum(<replaceable
class="parameter">Y</replaceable>)^2/<replaceable
......@@ -13360,6 +13399,7 @@ SELECT xmlagg(x) FROM (SELECT x FROM test ORDER BY y DESC) AS tab;
<type>double precision</type> for floating-point arguments,
otherwise <type>numeric</type>
</entry>
<entry>All types apart from floating-point types</entry>
<entry>historical alias for <function>stddev_samp</function></entry>
</row>
......@@ -13383,6 +13423,7 @@ SELECT xmlagg(x) FROM (SELECT x FROM test ORDER BY y DESC) AS tab;
<type>double precision</type> for floating-point arguments,
otherwise <type>numeric</type>
</entry>
<entry>All types apart from floating-point types</entry>
<entry>population standard deviation of the input values</entry>
</row>
......@@ -13406,6 +13447,7 @@ SELECT xmlagg(x) FROM (SELECT x FROM test ORDER BY y DESC) AS tab;
<type>double precision</type> for floating-point arguments,
otherwise <type>numeric</type>
</entry>
<entry>All types apart from floating-point types</entry>
<entry>sample standard deviation of the input values</entry>
</row>
......@@ -13425,6 +13467,7 @@ SELECT xmlagg(x) FROM (SELECT x FROM test ORDER BY y DESC) AS tab;
<type>double precision</type> for floating-point arguments,
otherwise <type>numeric</type>
</entry>
<entry>All types apart from floating-point types</entry>
<entry>historical alias for <function>var_samp</function></entry>
</row>
......@@ -13448,6 +13491,7 @@ SELECT xmlagg(x) FROM (SELECT x FROM test ORDER BY y DESC) AS tab;
<type>double precision</type> for floating-point arguments,
otherwise <type>numeric</type>
</entry>
<entry>All types apart from floating-point types</entry>
<entry>population variance of the input values (square of the population standard deviation)</entry>
</row>
......@@ -13471,6 +13515,7 @@ SELECT xmlagg(x) FROM (SELECT x FROM test ORDER BY y DESC) AS tab;
<type>double precision</type> for floating-point arguments,
otherwise <type>numeric</type>
</entry>
<entry>All types apart from floating-point types</entry>
<entry>sample variance of the input values (square of the sample standard deviation)</entry>
</row>
</tbody>
......@@ -13495,13 +13540,14 @@ SELECT xmlagg(x) FROM (SELECT x FROM test ORDER BY y DESC) AS tab;
<table id="functions-orderedset-table">
<title>Ordered-Set Aggregate Functions</title>
<tgroup cols="5">
<tgroup cols="6">
<thead>
<row>
<entry>Function</entry>
<entry>Direct Argument Type(s)</entry>
<entry>Aggregated Argument Type(s)</entry>
<entry>Return Type</entry>
<entry>Partial Mode</entry>
<entry>Description</entry>
</row>
</thead>
......@@ -13524,6 +13570,7 @@ SELECT xmlagg(x) FROM (SELECT x FROM test ORDER BY y DESC) AS tab;
<entry>
same as sort expression
</entry>
<entry>No</entry>
<entry>
returns the most frequent input value (arbitrarily choosing the first
one if there are multiple equally-frequent results)
......@@ -13550,6 +13597,7 @@ SELECT xmlagg(x) FROM (SELECT x FROM test ORDER BY y DESC) AS tab;
<entry>
same as sort expression
</entry>
<entry>No</entry>
<entry>
continuous percentile: returns a value corresponding to the specified
fraction in the ordering, interpolating between adjacent input items if
......@@ -13570,6 +13618,7 @@ SELECT xmlagg(x) FROM (SELECT x FROM test ORDER BY y DESC) AS tab;
<entry>
array of sort expression's type
</entry>
<entry>No</entry>
<entry>
multiple continuous percentile: returns an array of results matching
the shape of the <literal>fractions</literal> parameter, with each
......@@ -13594,6 +13643,7 @@ SELECT xmlagg(x) FROM (SELECT x FROM test ORDER BY y DESC) AS tab;
<entry>
same as sort expression
</entry>
<entry>No</entry>
<entry>
discrete percentile: returns the first input value whose position in
the ordering equals or exceeds the specified fraction
......@@ -13613,6 +13663,7 @@ SELECT xmlagg(x) FROM (SELECT x FROM test ORDER BY y DESC) AS tab;
<entry>
array of sort expression's type
</entry>
<entry>No</entry>
<entry>
multiple discrete percentile: returns an array of results matching the
shape of the <literal>fractions</literal> parameter, with each non-null
......@@ -13651,13 +13702,14 @@ SELECT xmlagg(x) FROM (SELECT x FROM test ORDER BY y DESC) AS tab;
<table id="functions-hypothetical-table">
<title>Hypothetical-Set Aggregate Functions</title>
<tgroup cols="5">
<tgroup cols="6">
<thead>
<row>
<entry>Function</entry>
<entry>Direct Argument Type(s)</entry>
<entry>Aggregated Argument Type(s)</entry>
<entry>Return Type</entry>
<entry>Partial Mode</entry>
<entry>Description</entry>
</row>
</thead>
......@@ -13681,6 +13733,7 @@ SELECT xmlagg(x) FROM (SELECT x FROM test ORDER BY y DESC) AS tab;
<entry>
<type>bigint</type>
</entry>
<entry>No</entry>
<entry>
rank of the hypothetical row, with gaps for duplicate rows
</entry>
......@@ -13703,6 +13756,7 @@ SELECT xmlagg(x) FROM (SELECT x FROM test ORDER BY y DESC) AS tab;
<entry>
<type>bigint</type>
</entry>
<entry>No</entry>
<entry>
rank of the hypothetical row, without gaps
</entry>
......@@ -13725,6 +13779,7 @@ SELECT xmlagg(x) FROM (SELECT x FROM test ORDER BY y DESC) AS tab;
<entry>
<type>double precision</type>
</entry>
<entry>No</entry>
<entry>
relative rank of the hypothetical row, ranging from 0 to 1
</entry>
......@@ -13747,6 +13802,7 @@ SELECT xmlagg(x) FROM (SELECT x FROM test ORDER BY y DESC) AS tab;
<entry>
<type>double precision</type>
</entry>
<entry>No</entry>
<entry>
relative rank of the hypothetical row, ranging from
1/<replaceable>N</> to 1
......
Markdown is supported
0% or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment