public inbox for [email protected]
help / color / mirror / Atom feed[PATCH 1/3] Add operator <->(box, point)
3+ messages / 3 participants
[nested] [flat]
* [PATCH 1/3] Add operator <->(box, point)
@ 2019-03-07 17:22 Nikita Glukhov <[email protected]>
0 siblings, 0 replies; 3+ messages in thread
From: Nikita Glukhov @ 2019-03-07 17:22 UTC (permalink / raw)
---
src/backend/utils/adt/geo_ops.c | 12 +++++
src/include/catalog/pg_operator.dat | 5 +-
src/include/catalog/pg_proc.dat | 3 ++
src/test/regress/expected/geometry.out | 96 +++++++++++++++++-----------------
src/test/regress/sql/geometry.sql | 2 +-
5 files changed, 68 insertions(+), 50 deletions(-)
diff --git a/src/backend/utils/adt/geo_ops.c b/src/backend/utils/adt/geo_ops.c
index 28e85e3..a8f9111 100644
--- a/src/backend/utils/adt/geo_ops.c
+++ b/src/backend/utils/adt/geo_ops.c
@@ -2419,6 +2419,18 @@ dist_pb(PG_FUNCTION_ARGS)
}
/*
+ * Distance from a box to a point
+ */
+Datum
+dist_bp(PG_FUNCTION_ARGS)
+{
+ BOX *box = PG_GETARG_BOX_P(0);
+ Point *pt = PG_GETARG_POINT_P(1);
+
+ PG_RETURN_FLOAT8(box_closept_point(NULL, box, pt));
+}
+
+/*
* Distance from a lseg to a line
*/
Datum
diff --git a/src/include/catalog/pg_operator.dat b/src/include/catalog/pg_operator.dat
index 06aec07..ebace5a 100644
--- a/src/include/catalog/pg_operator.dat
+++ b/src/include/catalog/pg_operator.dat
@@ -666,7 +666,10 @@
oprresult => 'float8', oprcode => 'dist_ps' },
{ oid => '615', descr => 'distance between',
oprname => '<->', oprleft => 'point', oprright => 'box',
- oprresult => 'float8', oprcode => 'dist_pb' },
+ oprresult => 'float8', oprcom => '<->(box,point)', oprcode => 'dist_pb' },
+{ oid => '606', descr => 'distance between',
+ oprname => '<->', oprleft => 'box', oprright => 'point',
+ oprresult => 'float8', oprcom => '<->(point,box)', oprcode => 'dist_bp' },
{ oid => '616', descr => 'distance between',
oprname => '<->', oprleft => 'lseg', oprright => 'line',
oprresult => 'float8', oprcode => 'dist_sl' },
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index 562c540..3800150 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -1062,6 +1062,9 @@
{ oid => '364',
proname => 'dist_pb', prorettype => 'float8', proargtypes => 'point box',
prosrc => 'dist_pb' },
+{ oid => '357',
+ proname => 'dist_bp', prorettype => 'float8', proargtypes => 'box point',
+ prosrc => 'dist_bp' },
{ oid => '365',
proname => 'dist_sb', prorettype => 'float8', proargtypes => 'lseg box',
prosrc => 'dist_sb' },
diff --git a/src/test/regress/expected/geometry.out b/src/test/regress/expected/geometry.out
index 055d32c..5efe80a 100644
--- a/src/test/regress/expected/geometry.out
+++ b/src/test/regress/expected/geometry.out
@@ -602,54 +602,54 @@ SELECT p.f1, l.s, p.f1 <-> l.s FROM POINT_TBL p, LSEG_TBL l;
(72 rows)
-- Distance to box
-SELECT p.f1, b.f1, p.f1 <-> b.f1 FROM POINT_TBL p, BOX_TBL b;
- f1 | f1 | ?column?
--------------------+---------------------+--------------------
- (0,0) | (2,2),(0,0) | 0
- (0,0) | (3,3),(1,1) | 1.41421356237
- (0,0) | (-2,2),(-8,-10) | 2
- (0,0) | (2.5,3.5),(2.5,2.5) | 3.53553390593
- (0,0) | (3,3),(3,3) | 4.24264068712
- (-10,0) | (2,2),(0,0) | 10
- (-10,0) | (3,3),(1,1) | 11.0453610172
- (-10,0) | (-2,2),(-8,-10) | 2
- (-10,0) | (2.5,3.5),(2.5,2.5) | 12.747548784
- (-10,0) | (3,3),(3,3) | 13.3416640641
- (-3,4) | (2,2),(0,0) | 3.60555127546
- (-3,4) | (3,3),(1,1) | 4.12310562562
- (-3,4) | (-2,2),(-8,-10) | 2
- (-3,4) | (2.5,3.5),(2.5,2.5) | 5.52268050859
- (-3,4) | (3,3),(3,3) | 6.0827625303
- (5.1,34.5) | (2,2),(0,0) | 32.6475113906
- (5.1,34.5) | (3,3),(1,1) | 31.5699223946
- (5.1,34.5) | (-2,2),(-8,-10) | 33.2664996656
- (5.1,34.5) | (2.5,3.5),(2.5,2.5) | 31.108841187
- (5.1,34.5) | (3,3),(3,3) | 31.5699223946
- (-5,-12) | (2,2),(0,0) | 13
- (-5,-12) | (3,3),(1,1) | 14.3178210633
- (-5,-12) | (-2,2),(-8,-10) | 2
- (-5,-12) | (2.5,3.5),(2.5,2.5) | 16.3248277173
- (-5,-12) | (3,3),(3,3) | 17
- (1e-300,-1e-300) | (2,2),(0,0) | 1.41421356237e-300
- (1e-300,-1e-300) | (3,3),(1,1) | 1.41421356237
- (1e-300,-1e-300) | (-2,2),(-8,-10) | 2
- (1e-300,-1e-300) | (2.5,3.5),(2.5,2.5) | 3.53553390593
- (1e-300,-1e-300) | (3,3),(3,3) | 4.24264068712
- (1e+300,Infinity) | (2,2),(0,0) | Infinity
- (1e+300,Infinity) | (3,3),(1,1) | Infinity
- (1e+300,Infinity) | (-2,2),(-8,-10) | Infinity
- (1e+300,Infinity) | (2.5,3.5),(2.5,2.5) | Infinity
- (1e+300,Infinity) | (3,3),(3,3) | Infinity
- (NaN,NaN) | (2,2),(0,0) | NaN
- (NaN,NaN) | (3,3),(1,1) | NaN
- (NaN,NaN) | (-2,2),(-8,-10) | NaN
- (NaN,NaN) | (2.5,3.5),(2.5,2.5) | NaN
- (NaN,NaN) | (3,3),(3,3) | NaN
- (10,10) | (2,2),(0,0) | 11.313708499
- (10,10) | (3,3),(1,1) | 9.89949493661
- (10,10) | (-2,2),(-8,-10) | 14.4222051019
- (10,10) | (2.5,3.5),(2.5,2.5) | 9.92471662064
- (10,10) | (3,3),(3,3) | 9.89949493661
+SELECT p.f1, b.f1, p.f1 <-> b.f1, b.f1 <-> p.f1 FROM POINT_TBL p, BOX_TBL b;
+ f1 | f1 | ?column? | ?column?
+-------------------+---------------------+--------------------+--------------------
+ (0,0) | (2,2),(0,0) | 0 | 0
+ (0,0) | (3,3),(1,1) | 1.41421356237 | 1.41421356237
+ (0,0) | (-2,2),(-8,-10) | 2 | 2
+ (0,0) | (2.5,3.5),(2.5,2.5) | 3.53553390593 | 3.53553390593
+ (0,0) | (3,3),(3,3) | 4.24264068712 | 4.24264068712
+ (-10,0) | (2,2),(0,0) | 10 | 10
+ (-10,0) | (3,3),(1,1) | 11.0453610172 | 11.0453610172
+ (-10,0) | (-2,2),(-8,-10) | 2 | 2
+ (-10,0) | (2.5,3.5),(2.5,2.5) | 12.747548784 | 12.747548784
+ (-10,0) | (3,3),(3,3) | 13.3416640641 | 13.3416640641
+ (-3,4) | (2,2),(0,0) | 3.60555127546 | 3.60555127546
+ (-3,4) | (3,3),(1,1) | 4.12310562562 | 4.12310562562
+ (-3,4) | (-2,2),(-8,-10) | 2 | 2
+ (-3,4) | (2.5,3.5),(2.5,2.5) | 5.52268050859 | 5.52268050859
+ (-3,4) | (3,3),(3,3) | 6.0827625303 | 6.0827625303
+ (5.1,34.5) | (2,2),(0,0) | 32.6475113906 | 32.6475113906
+ (5.1,34.5) | (3,3),(1,1) | 31.5699223946 | 31.5699223946
+ (5.1,34.5) | (-2,2),(-8,-10) | 33.2664996656 | 33.2664996656
+ (5.1,34.5) | (2.5,3.5),(2.5,2.5) | 31.108841187 | 31.108841187
+ (5.1,34.5) | (3,3),(3,3) | 31.5699223946 | 31.5699223946
+ (-5,-12) | (2,2),(0,0) | 13 | 13
+ (-5,-12) | (3,3),(1,1) | 14.3178210633 | 14.3178210633
+ (-5,-12) | (-2,2),(-8,-10) | 2 | 2
+ (-5,-12) | (2.5,3.5),(2.5,2.5) | 16.3248277173 | 16.3248277173
+ (-5,-12) | (3,3),(3,3) | 17 | 17
+ (1e-300,-1e-300) | (2,2),(0,0) | 1.41421356237e-300 | 1.41421356237e-300
+ (1e-300,-1e-300) | (3,3),(1,1) | 1.41421356237 | 1.41421356237
+ (1e-300,-1e-300) | (-2,2),(-8,-10) | 2 | 2
+ (1e-300,-1e-300) | (2.5,3.5),(2.5,2.5) | 3.53553390593 | 3.53553390593
+ (1e-300,-1e-300) | (3,3),(3,3) | 4.24264068712 | 4.24264068712
+ (1e+300,Infinity) | (2,2),(0,0) | Infinity | Infinity
+ (1e+300,Infinity) | (3,3),(1,1) | Infinity | Infinity
+ (1e+300,Infinity) | (-2,2),(-8,-10) | Infinity | Infinity
+ (1e+300,Infinity) | (2.5,3.5),(2.5,2.5) | Infinity | Infinity
+ (1e+300,Infinity) | (3,3),(3,3) | Infinity | Infinity
+ (NaN,NaN) | (2,2),(0,0) | NaN | NaN
+ (NaN,NaN) | (3,3),(1,1) | NaN | NaN
+ (NaN,NaN) | (-2,2),(-8,-10) | NaN | NaN
+ (NaN,NaN) | (2.5,3.5),(2.5,2.5) | NaN | NaN
+ (NaN,NaN) | (3,3),(3,3) | NaN | NaN
+ (10,10) | (2,2),(0,0) | 11.313708499 | 11.313708499
+ (10,10) | (3,3),(1,1) | 9.89949493661 | 9.89949493661
+ (10,10) | (-2,2),(-8,-10) | 14.4222051019 | 14.4222051019
+ (10,10) | (2.5,3.5),(2.5,2.5) | 9.92471662064 | 9.92471662064
+ (10,10) | (3,3),(3,3) | 9.89949493661 | 9.89949493661
(45 rows)
-- Distance to path
diff --git a/src/test/regress/sql/geometry.sql b/src/test/regress/sql/geometry.sql
index ce98b3e..9fbd123 100644
--- a/src/test/regress/sql/geometry.sql
+++ b/src/test/regress/sql/geometry.sql
@@ -77,7 +77,7 @@ SELECT p.f1, l.s, p.f1 <-> l.s FROM POINT_TBL p, LINE_TBL l;
SELECT p.f1, l.s, p.f1 <-> l.s FROM POINT_TBL p, LSEG_TBL l;
-- Distance to box
-SELECT p.f1, b.f1, p.f1 <-> b.f1 FROM POINT_TBL p, BOX_TBL b;
+SELECT p.f1, b.f1, p.f1 <-> b.f1, b.f1 <-> p.f1 FROM POINT_TBL p, BOX_TBL b;
-- Distance to path
SELECT p.f1, p1.f1, p.f1 <-> p1.f1 FROM POINT_TBL p, PATH_TBL p1;
--
2.7.4
--------------B01ADF66983FA504E371CA13
Content-Type: text/x-patch;
name="0002-Add-box-point-distance-operator-to-GiST-box_ops-v01.patch"
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
filename*0="0002-Add-box-point-distance-operator-to-GiST-box_ops-v01.pat";
filename*1="ch"
^ permalink raw reply [nested|flat] 3+ messages in thread
* Valgrind errors on 32-bit OS
@ 2023-07-10 07:51 [email protected]
0 siblings, 0 replies; 3+ messages in thread
From: [email protected] @ 2023-07-10 07:51 UTC (permalink / raw)
To: pgsql-hackers; +Cc: Anton Voloshin <[email protected]>
Greetings, everyone!
While working on an extension, I've found myself using valgrind on a
32-bit OS (Debian 11)
and after executing any query (even 'select 1;') under valgrind I've
been shown the same error
everytime:
==00:00:00:18.109 2528== VALGRINDERROR-BEGIN
==00:00:00:18.109 2528== Use of uninitialised value of size 4
==00:00:00:18.109 2528== at 0x645B52: pg_comp_crc32c_sb8
(pg_crc32c_sb8.c:79)
==00:00:00:18.109 2528== by 0x24295F: XLogRecordAssemble
(xloginsert.c:780)
==00:00:00:18.109 2528== by 0x24295F: XLogInsert (xloginsert.c:459)
==00:00:00:18.109 2528== by 0x4B693B: LogCurrentRunningXacts
(standby.c:1099)
==00:00:00:18.109 2528== by 0x4B693B: LogStandbySnapshot
(standby.c:1055)
==00:00:00:18.109 2528== by 0x43BECF: BackgroundWriterMain
(bgwriter.c:336)
==00:00:00:18.109 2528== by 0x249D8A: AuxiliaryProcessMain
(bootstrap.c:446)
==00:00:00:18.109 2528== by 0x448B11: StartChildProcess
(postmaster.c:5445)
==00:00:00:18.109 2528== by 0x449F57: reaper (postmaster.c:2907)
==00:00:00:18.109 2528== by 0x486D587: ??? (in
/usr/lib/i386-linux-gnu/libpthread-2.31.so)
==00:00:00:18.109 2528== Uninitialised value was created by a stack
allocation
==00:00:00:18.109 2528== at 0x4B682F: LogStandbySnapshot
(standby.c:1018)
I've been able to reproduce this on branches from REL_11_STABLE up to
current master.
Valgrind version is 3.21.0.
I was wondering, why does this error occur only on 32-bit OS and not
64-bit?
I found three threads:
About issues with valgrind and padding -
https://www.postgresql.org/message-id/flat/1082573393.7010.27.camel%40tokyo
About sanitizers (and valgrind) in general -
https://www.postgresql.org/message-id/flat/20160321130850.6ed6f598%40fujitsu
About valgrind suppressions -
https://www.postgresql.org/message-id/flat/4dfabec2-a3ad-0546-2d62-f816c97edd0c%402ndQuadrant.com
and after reading those decided to look for existing valgrind
suppressions.
And I've found just what I was looking for:
{
padding_XLogRecData_CRC
Memcheck:Value8
fun:pg_comp_crc32c*
fun:XLogRecordAssemble
}
Supression for this (group of) function(s), but for 8-byte chunks of
memory.
So the suggestion is to add a suppression for 4-byte values in this
function.
The patch is attached.
Oleg Tselebrovskiy, Postgres Pro
Attachments:
[text/x-diff] 32-bit-supression.patch (370B, ../../[email protected]/2-32-bit-supression.patch)
download | inline diff:
diff --git a/src/tools/valgrind.supp b/src/tools/valgrind.supp
index 7ea464c8094..0055cf14625 100644
--- a/src/tools/valgrind.supp
+++ b/src/tools/valgrind.supp
@@ -23,6 +23,14 @@
fun:pgstat_write_statsfiles
}
+{
+ padding_XLogRecData_CRC_32_bit
+ Memcheck:Value4
+
+ fun:pg_comp_crc32c*
+ fun:XLogRecordAssemble
+}
+
{
padding_XLogRecData_CRC
Memcheck:Value8
^ permalink raw reply [nested|flat] 3+ messages in thread
* [PATCH v16 6/8] Row pattern recognition patch (docs).
@ 2024-04-12 06:49 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 3+ messages in thread
From: Tatsuo Ishii @ 2024-04-12 06:49 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 80 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 38 ++++++++++++++++-
3 files changed, 170 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..cf18dd887e 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,86 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Row pattern common syntax can be used to perform row pattern recognition
+ in a query. Row pattern common syntax includes two sub
+ clauses: <literal>DEFINE</literal>
+ and <literal>PATTERN</literal>. <literal>DEFINE</literal> defines
+ definition variables along with an expression. The expression must be a
+ logical expression, which means it must
+ return <literal>TRUE</literal>, <literal>FALSE</literal>
+ or <literal>NULL</literal>. The expression may comprise column references
+ and functions. Window functions, aggregate functions and subqueries are
+ not allowed. An example of <literal>DEFINE</literal> is as follows.
+
+<programlisting>
+DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+</programlisting>
+
+ Note that <function>PREV</function> returns the price column in the
+ previous row if it's called in a context of row pattern recognition. So in
+ the second line the definition variable "UP" is <literal>TRUE</literal>
+ when the price column in the current row is greater than the price column
+ in the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ the price column in the current row is lower than the price column in the
+ previous row.
+ </para>
+ <para>
+ Once <literal>DEFINE</literal> exists, <literal>PATTERN</literal> can be
+ used. <literal>PATTERN</literal> defines a sequence of rows that satisfies
+ certain conditions. For example following <literal>PATTERN</literal>
+ defines that a row starts with the condition "LOWPRICE", then one or more
+ rows satisfy "UP" and finally one or more rows satisfy "DOWN". Note that
+ "+" means one or more matches. Also you can use "*", which means zero or
+ more matches. If a sequence of rows which satisfies the PATTERN is found,
+ in the starting row of the sequence of rows all window functions and
+ aggregates are shown in the target list. Note that aggregations only look
+ into the matched rows, rather than whole frame. In the second or
+ subsequent rows all window functions and aggregates are NULL. For rows
+ that do not match the PATTERN, all window functions and aggregates are
+ shown AS NULL too, except count which shows 0. This is because the
+ unmatched rows are in an empty frame. Example of
+ a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price,
+ first_value(price) OVER w,
+ max(price) OVER w,
+ count(price) OVER w
+FROM stock,
+ WINDOW w AS (
+ PARTITION BY company
+ ORDER BY tdate
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ INITIAL
+ PATTERN (LOWPRICE UP+ DOWN+)
+ DEFINE
+ LOWPRICE AS price <= 100,
+ UP AS price > PREV(price),
+ DOWN AS price < PREV(price)
+);
+</programlisting>
+<screen>
+ company | tdate | price | first_value | max | count
+----------+------------+-------+-------------+-----+-------
+ company1 | 2023-07-01 | 100 | 100 | 200 | 4
+ company1 | 2023-07-02 | 200 | | |
+ company1 | 2023-07-03 | 150 | | |
+ company1 | 2023-07-04 | 140 | | |
+ company1 | 2023-07-05 | 150 | | | 0
+ company1 | 2023-07-06 | 90 | 90 | 130 | 4
+ company1 | 2023-07-07 | 110 | | |
+ company1 | 2023-07-08 | 130 | | |
+ company1 | 2023-07-09 | 120 | | |
+ company1 | 2023-07-10 | 130 | | | 0
+</screen>
+ </para>
+
<para>
When a query involves multiple window functions, it is possible to write
out each one with a separate <literal>OVER</literal> clause, but this is
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 8dfb42ad4d..f6ee99fe19 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -23123,6 +23123,7 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
</tbody>
</tgroup>
</table>
@@ -23162,6 +23163,59 @@ SELECT count(*) FROM sometable;
Other frame specifications can be used to obtain other effects.
</para>
+ <para>
+ Row pattern recognition navigation functions are listed in
+ <xref linkend="functions-rpr-navigation-table"/>. These functions
+ can be used to describe DEFINE clause of Row pattern recognition.
+ </para>
+
+ <table id="functions-rpr-navigation-table">
+ <title>Row Pattern Navigation Functions</title>
+ <tgroup cols="1">
+ <thead>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ Function
+ </para>
+ <para>
+ Description
+ </para></entry>
+ </row>
+ </thead>
+
+ <tbody>
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>prev</primary>
+ </indexterm>
+ <function>prev</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the previous row;
+ returns NULL if there is no previous row in the window frame.
+ </para></entry>
+ </row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>next</primary>
+ </indexterm>
+ <function>next</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Returns the column value at the next row;
+ returns NULL if there is no next row in the window frame.
+ </para></entry>
+ </row>
+
+ </tbody>
+ </tgroup>
+ </table>
+
<note>
<para>
The SQL standard defines a <literal>RESPECT NULLS</literal> or
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index 066aed44e6..8f18718d58 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -969,8 +969,8 @@ WINDOW <replaceable class="parameter">window_name</replaceable> AS ( <replaceabl
The <replaceable class="parameter">frame_clause</replaceable> can be one of
<synopsis>
-{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
-{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ]
+{ RANGE | ROWS | GROUPS } <replaceable>frame_start</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
+{ RANGE | ROWS | GROUPS } BETWEEN <replaceable>frame_start</replaceable> AND <replaceable>frame_end</replaceable> [ <replaceable>frame_exclusion</replaceable> ] [row_pattern_common_syntax]
</synopsis>
where <replaceable>frame_start</replaceable>
@@ -1077,6 +1077,40 @@ EXCLUDE NO OTHERS
a given peer group will be in the frame or excluded from it.
</para>
+ <para>
+ The
+ optional <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ defines the <firstterm>row pattern recognition condition</firstterm> for
+ this
+ window. <replaceable class="parameter">row_pattern_common_syntax</replaceable>
+ includes following subclauses. <literal>AFTER MATCH SKIP PAST LAST
+ ROW</literal> or <literal>AFTER MATCH SKIP TO NEXT ROW</literal> controls
+ how to proceed to next row position after a match
+ found. With <literal>AFTER MATCH SKIP PAST LAST ROW</literal> (the
+ default) next row position is next to the last row of previous match. On
+ the other hand, with <literal>AFTER MATCH SKIP TO NEXT ROW</literal> next
+ row position is always next to the last row of previous
+ match. <literal>DEFINE</literal> defines definition variables along with a
+ boolean expression. <literal>PATTERN</literal> defines a sequence of rows
+ that satisfies certain conditions using variables defined
+ in <literal>DEFINE</literal> clause. If the variable is not defined in
+ the <literal>DEFINE</literal> clause, it is implicitly assumed
+ following is defined in the <literal>DEFINE</literal> clause.
+
+<synopsis>
+<literal>variable_name</literal> AS TRUE
+</synopsis>
+
+ Note that the maximu number of variables defined
+ in <literal>DEFINE</literal> clause is 26.
+
+<synopsis>
+[ AFTER MATCH SKIP PAST LAST ROW | AFTER MATCH SKIP TO NEXT ROW ]
+PATTERN <replaceable class="parameter">pattern_variable_name</replaceable>[+] [, ...]
+DEFINE <replaceable class="parameter">definition_varible_name</replaceable> AS <replaceable class="parameter">expression</replaceable> [, ...]
+</synopsis>
+ </para>
+
<para>
The purpose of a <literal>WINDOW</literal> clause is to specify the
behavior of <firstterm>window functions</firstterm> appearing in the query's
--
2.25.1
----Next_Part(Fri_Apr_12_16_09_08_2024_262)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v16-0007-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 3+ messages in thread
end of thread, other threads:[~2024-04-12 06:49 UTC | newest]
Thread overview: 3+ messages (download: mbox mbox.gz follow: Atom feed)
-- links below jump to the message on this page --
2019-03-07 17:22 [PATCH 1/3] Add operator <->(box, point) Nikita Glukhov <[email protected]>
2023-07-10 07:51 Valgrind errors on 32-bit OS [email protected]
2024-04-12 06:49 [PATCH v16 6/8] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
This inbox is served by agora; see mirroring instructions
for how to clone and mirror all data and code used for this inbox