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help / color / mirror / Atom feed[PATCH 2/2] Invoke RelationBuildPartitionDesc lazily
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* [PATCH 2/2] Invoke RelationBuildPartitionDesc lazily
@ 2019-11-13 18:34 Alvaro Herrera <[email protected]>
0 siblings, 0 replies; 4+ messages in thread
From: Alvaro Herrera @ 2019-11-13 18:34 UTC (permalink / raw)
---
src/backend/partitioning/partdesc.c | 17 ++++++++++++++++-
src/backend/utils/cache/relcache.c | 22 +++++-----------------
src/include/partitioning/partdesc.h | 2 +-
src/include/utils/rel.h | 6 ------
4 files changed, 22 insertions(+), 25 deletions(-)
diff --git a/src/backend/partitioning/partdesc.c b/src/backend/partitioning/partdesc.c
index c551df6673..8171eb03ca 100644
--- a/src/backend/partitioning/partdesc.c
+++ b/src/backend/partitioning/partdesc.c
@@ -34,6 +34,7 @@
#include "utils/rel.h"
#include "utils/syscache.h"
+
typedef struct PartitionDirectoryData
{
MemoryContext pdir_mcxt;
@@ -47,6 +48,20 @@ typedef struct PartitionDirectoryEntry
PartitionDesc pd;
} PartitionDirectoryEntry;
+
+static void RelationBuildPartitionDesc(Relation rel);
+
+PartitionDesc
+RelationGetPartitionDesc(Relation rel)
+{
+ Assert(rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE);
+
+ if (rel->rd_partdesc == NULL)
+ RelationBuildPartitionDesc(rel);
+
+ return rel->rd_partdesc;
+}
+
/*
* RelationBuildPartitionDesc
* Form rel's partition descriptor, and store in relcache entry
@@ -57,7 +72,7 @@ typedef struct PartitionDirectoryEntry
* that's sufficient to prevent that can assume that rd_partdesc
* won't change underneath it.
*/
-void
+static void
RelationBuildPartitionDesc(Relation rel)
{
PartitionDesc partdesc;
diff --git a/src/backend/utils/cache/relcache.c b/src/backend/utils/cache/relcache.c
index ad1ff01b32..5ef61d187a 100644
--- a/src/backend/utils/cache/relcache.c
+++ b/src/backend/utils/cache/relcache.c
@@ -1165,20 +1165,17 @@ RelationBuildDesc(Oid targetRelId, bool insertIt)
relation->rd_fkeylist = NIL;
relation->rd_fkeyvalid = false;
- /* if a partitioned table, initialize key and partition descriptor info */
+ /* if a partitioned table, initialize key info */
if (relation->rd_rel->relkind == RELKIND_PARTITIONED_TABLE)
- {
RelationBuildPartitionKey(relation);
- RelationBuildPartitionDesc(relation);
- }
else
{
relation->rd_partkey = NULL;
relation->rd_partkeycxt = NULL;
- relation->rd_partdesc = NULL;
- relation->rd_pdcxt = NULL;
}
- /* ... but partcheck is not loaded till asked for */
+ /* ... but partcheck and partdesc are not loaded till asked for */
+ relation->rd_pdcxt = NULL;
+ relation->rd_partdesc = NULL;
relation->rd_partcheck = NIL;
relation->rd_partcheckvalid = false;
relation->rd_partcheckcxt = NULL;
@@ -3908,7 +3905,7 @@ RelationCacheInitializePhase3(void)
}
/*
- * Reload the partition key and descriptor for a partitioned table.
+ * Reload the partition key for a partitioned table.
*/
if (relation->rd_rel->relkind == RELKIND_PARTITIONED_TABLE &&
relation->rd_partkey == NULL)
@@ -3919,15 +3916,6 @@ RelationCacheInitializePhase3(void)
restart = true;
}
- if (relation->rd_rel->relkind == RELKIND_PARTITIONED_TABLE &&
- relation->rd_partdesc == NULL)
- {
- RelationBuildPartitionDesc(relation);
- Assert(relation->rd_partdesc != NULL);
-
- restart = true;
- }
-
if (relation->rd_tableam == NULL &&
(relation->rd_rel->relkind == RELKIND_RELATION ||
relation->rd_rel->relkind == RELKIND_SEQUENCE ||
diff --git a/src/include/partitioning/partdesc.h b/src/include/partitioning/partdesc.h
index 38712c1550..d30c8feb48 100644
--- a/src/include/partitioning/partdesc.h
+++ b/src/include/partitioning/partdesc.h
@@ -29,7 +29,7 @@ typedef struct PartitionDescData
PartitionBoundInfo boundinfo; /* collection of partition bounds */
} PartitionDescData;
-extern void RelationBuildPartitionDesc(Relation rel);
+extern PartitionDesc RelationGetPartitionDesc(Relation rel);
extern PartitionDirectory CreatePartitionDirectory(MemoryContext mcxt);
extern PartitionDesc PartitionDirectoryLookup(PartitionDirectory, Relation);
diff --git a/src/include/utils/rel.h b/src/include/utils/rel.h
index 8b8b237f0d..4ec27a63e8 100644
--- a/src/include/utils/rel.h
+++ b/src/include/utils/rel.h
@@ -603,12 +603,6 @@ typedef struct ViewOptions
*/
#define RelationGetPartitionKey(relation) ((relation)->rd_partkey)
-/*
- * RelationGetPartitionDesc
- * Returns partition descriptor for a relation.
- */
-#define RelationGetPartitionDesc(relation) ((relation)->rd_partdesc)
-
/* routines in utils/cache/relcache.c */
extern void RelationIncrementReferenceCount(Relation rel);
extern void RelationDecrementReferenceCount(Relation rel);
--
2.20.1
--OXfL5xGRrasGEqWY--
^ permalink raw reply [nested|flat] 4+ messages in thread
* [PATCH v2 5/7] Row pattern recognition patch (docs).
@ 2023-06-26 08:05 Tatsuo Ishii <[email protected]>
0 siblings, 0 replies; 4+ messages in thread
From: Tatsuo Ishii @ 2023-06-26 08:05 UTC (permalink / raw)
---
doc/src/sgml/advanced.sgml | 52 +++++++++++++++++++++++++++
doc/src/sgml/func.sgml | 69 ++++++++++++++++++++++++++++++++++++
doc/src/sgml/ref/select.sgml | 29 +++++++++++++--
3 files changed, 148 insertions(+), 2 deletions(-)
diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index 755c9f1485..e9bbd5bc7c 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -537,6 +537,58 @@ WHERE pos < 3;
<literal>rank</literal> less than 3.
</para>
+ <para>
+ Window function <function>rpr</function> can be used with row pattern
+ common syntax to perform row pattern recognition in a query. Row pattern
+ common syntax includes two sub clauses. <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>. Moreover if the expression comprises a column
+ reference, it must be the argument of <function>rpr</function>. 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 price column in the previous
+ row if it's called in a context of row pattern recognition. So in the
+ second line means the definition variable "UP" is <literal>TRUE</literal>
+ when price column in the current row is greater than the price column in
+ the previous row. Likewise, "DOWN" is <literal>TRUE</literal> when when
+ 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". If a
+ sequence of rows found, rpr returns the column at the starting row.
+ Example of a <literal>SELECT</literal> using the <literal>DEFINE</literal>
+ and <literal>PATTERN</literal> clause is as follows.
+
+<programlisting>
+SELECT company, tdate, price, rpr(price) OVER w FROM stock
+ WINDOW w AS (
+ PARTITION BY company
+ 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>
+ </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 5a47ce4343..8069c58ca5 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -21648,6 +21648,22 @@ SELECT count(*) FROM sometable;
returns <literal>NULL</literal> if there is no such row.
</para></entry>
</row>
+
+ <row>
+ <entry role="func_table_entry"><para role="func_signature">
+ <indexterm>
+ <primary>rpr</primary>
+ </indexterm>
+ <function>rpr</function> ( <parameter>value</parameter> <type>anyelement</type> )
+ <returnvalue>anyelement</returnvalue>
+ </para>
+ <para>
+ Perform row pattern recognition using column specified
+ by <parameter>value</parameter> and returns the value of the column if
+ current row is the first matching row;
+ returns <literal>NULL</literal> otherwise.
+ </para></entry>
+ </row>
</tbody>
</tgroup>
</table>
@@ -21687,6 +21703,59 @@ 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 0ee0cc7e64..16478a3950 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -966,8 +966,8 @@ 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>
@@ -1074,6 +1074,31 @@ 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.
+
+<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(Mon_Jun_26_17_45_07_2023_724)--
Content-Type: Text/X-Patch; charset=us-ascii
Content-Transfer-Encoding: 7bit
Content-Disposition: inline;
filename="v2-0006-Row-pattern-recognition-patch-tests.patch"
^ permalink raw reply [nested|flat] 4+ messages in thread
* Re: Small patch modifying variable name to reflect the logic involved
@ 2023-09-14 09:30 Daniel Gustafsson <[email protected]>
2023-09-15 17:50 ` Re: Small patch modifying variable name to reflect the logic involved Daniel Gustafsson <[email protected]>
0 siblings, 1 reply; 4+ messages in thread
From: Daniel Gustafsson @ 2023-09-14 09:30 UTC (permalink / raw)
To: Krishnakumar R <[email protected]>; +Cc: pgsql-hackers
> On 14 Sep 2023, at 08:28, Krishnakumar R <[email protected]> wrote:
> Please find a small patch to improve code readability by modifying
> variable name to reflect the logic involved - finding diff between end
> and start time of WAL sync.
- INSTR_TIME_ACCUM_DIFF(PendingWalStats.wal_sync_time, duration, start);
+ INSTR_TIME_SET_CURRENT(end);
+ INSTR_TIME_ACCUM_DIFF(PendingWalStats.wal_sync_time, end, start);
Agreed, the duration is the result of the INSTR_TIME_ACCUM_DIFF calculation,
not what's stored in the instr_time variable.
--
Daniel Gustafsson
^ permalink raw reply [nested|flat] 4+ messages in thread
* Re: Small patch modifying variable name to reflect the logic involved
2023-09-14 09:30 Re: Small patch modifying variable name to reflect the logic involved Daniel Gustafsson <[email protected]>
@ 2023-09-15 17:50 ` Daniel Gustafsson <[email protected]>
0 siblings, 0 replies; 4+ messages in thread
From: Daniel Gustafsson @ 2023-09-15 17:50 UTC (permalink / raw)
To: Krishnakumar R <[email protected]>; +Cc: pgsql-hackers
> On 14 Sep 2023, at 11:30, Daniel Gustafsson <[email protected]> wrote:
>
>> On 14 Sep 2023, at 08:28, Krishnakumar R <[email protected]> wrote:
>
>> Please find a small patch to improve code readability by modifying
>> variable name to reflect the logic involved - finding diff between end
>> and start time of WAL sync.
>
> - INSTR_TIME_ACCUM_DIFF(PendingWalStats.wal_sync_time, duration, start);
> + INSTR_TIME_SET_CURRENT(end);
> + INSTR_TIME_ACCUM_DIFF(PendingWalStats.wal_sync_time, end, start);
>
> Agreed, the duration is the result of the INSTR_TIME_ACCUM_DIFF calculation,
> not what's stored in the instr_time variable.
And done, with a small fixup to handle another occurrence in the same file.
--
Daniel Gustafsson
^ permalink raw reply [nested|flat] 4+ messages in thread
end of thread, other threads:[~2023-09-15 17:50 UTC | newest]
Thread overview: 4+ messages (download: mbox mbox.gz follow: Atom feed)
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2019-11-13 18:34 [PATCH 2/2] Invoke RelationBuildPartitionDesc lazily Alvaro Herrera <[email protected]>
2023-06-26 08:05 [PATCH v2 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
2023-09-14 09:30 Re: Small patch modifying variable name to reflect the logic involved Daniel Gustafsson <[email protected]>
2023-09-15 17:50 ` Re: Small patch modifying variable name to reflect the logic involved Daniel Gustafsson <[email protected]>
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