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[PATCH] Fix misuses of RelationNeedsWAL 2+ messages / 2 participants [nested] [flat]
* [PATCH] Fix misuses of RelationNeedsWAL @ 2021-01-13 06:52 Kyotaro Horiguchi <[email protected]> 0 siblings, 0 replies; 2+ messages in thread From: Kyotaro Horiguchi @ 2021-01-13 06:52 UTC (permalink / raw) The definition of the macro RelationNeedsWAL has been changed by c6b92041d3 to include conditions related to the WAL-skip optimization but some uses of the macro are not relevant to the optimization. That misuses are harmless for now as they are only executed while wal_level >= replica or WAL-skipping is inactive. However, this should be corrected to prevent future hazard. --- src/backend/catalog/pg_publication.c | 2 +- src/backend/optimizer/util/plancat.c | 2 +- src/include/utils/rel.h | 15 +++++++++++---- src/include/utils/snapmgr.h | 2 +- 4 files changed, 14 insertions(+), 7 deletions(-) diff --git a/src/backend/catalog/pg_publication.c b/src/backend/catalog/pg_publication.c index 5f8e1c64e1..f3060a4cf1 100644 --- a/src/backend/catalog/pg_publication.c +++ b/src/backend/catalog/pg_publication.c @@ -67,7 +67,7 @@ check_publication_add_relation(Relation targetrel) errdetail("System tables cannot be added to publications."))); /* UNLOGGED and TEMP relations cannot be part of publication. */ - if (!RelationNeedsWAL(targetrel)) + if (!RelationIsWalLogged(targetrel)) ereport(ERROR, (errcode(ERRCODE_INVALID_PARAMETER_VALUE), errmsg("table \"%s\" cannot be replicated", diff --git a/src/backend/optimizer/util/plancat.c b/src/backend/optimizer/util/plancat.c index da322b453e..0500efcdb9 100644 --- a/src/backend/optimizer/util/plancat.c +++ b/src/backend/optimizer/util/plancat.c @@ -126,7 +126,7 @@ get_relation_info(PlannerInfo *root, Oid relationObjectId, bool inhparent, relation = table_open(relationObjectId, NoLock); /* Temporary and unlogged relations are inaccessible during recovery. */ - if (!RelationNeedsWAL(relation) && RecoveryInProgress()) + if (!RelationIsWalLogged(relation) && RecoveryInProgress()) ereport(ERROR, (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), errmsg("cannot access temporary or unlogged relations during recovery"))); diff --git a/src/include/utils/rel.h b/src/include/utils/rel.h index 10b63982c0..810806a542 100644 --- a/src/include/utils/rel.h +++ b/src/include/utils/rel.h @@ -552,16 +552,23 @@ typedef struct ViewOptions (relation)->rd_smgr->smgr_targblock = (targblock); \ } while (0) +/* + * RelationIsPermanent + * True if relation is WAL-logged. + */ +#define RelationIsWalLogged(relation) \ + ((relation)->rd_rel->relpersistence == RELPERSISTENCE_PERMANENT) + /* * RelationNeedsWAL - * True if relation needs WAL. + * True if relation needs WAL at the time. * * Returns false if wal_level = minimal and this relation is created or * truncated in the current transaction. See "Skipping WAL for New * RelFileNode" in src/backend/access/transam/README. */ #define RelationNeedsWAL(relation) \ - ((relation)->rd_rel->relpersistence == RELPERSISTENCE_PERMANENT && \ + (RelationIsWalLogged(relation) && \ (XLogIsNeeded() || \ (relation->rd_createSubid == InvalidSubTransactionId && \ relation->rd_firstRelfilenodeSubid == InvalidSubTransactionId))) @@ -619,7 +626,7 @@ typedef struct ViewOptions */ #define RelationIsAccessibleInLogicalDecoding(relation) \ (XLogLogicalInfoActive() && \ - RelationNeedsWAL(relation) && \ + RelationIsWalLogged(relation) && \ (IsCatalogRelation(relation) || RelationIsUsedAsCatalogTable(relation))) /* @@ -635,7 +642,7 @@ typedef struct ViewOptions */ #define RelationIsLogicallyLogged(relation) \ (XLogLogicalInfoActive() && \ - RelationNeedsWAL(relation) && \ + RelationIsWalLogged(relation) && \ !IsCatalogRelation(relation)) /* routines in utils/cache/relcache.c */ diff --git a/src/include/utils/snapmgr.h b/src/include/utils/snapmgr.h index 579be352c5..7be922a9f1 100644 --- a/src/include/utils/snapmgr.h +++ b/src/include/utils/snapmgr.h @@ -37,7 +37,7 @@ */ #define RelationAllowsEarlyPruning(rel) \ ( \ - RelationNeedsWAL(rel) \ + RelationIsWalLogged(rel) \ && !IsCatalogRelation(rel) \ && !RelationIsAccessibleInLogicalDecoding(rel) \ ) -- 2.27.0 ----Next_Part(Wed_Jan_13_16_07_05_2021_621)---- ^ permalink raw reply [nested|flat] 2+ messages in thread
* [PATCH v6 5/7] Row pattern recognition patch (docs). @ 2023-09-12 05:22 Tatsuo Ishii <[email protected]> 0 siblings, 0 replies; 2+ messages in thread From: Tatsuo Ishii @ 2023-09-12 05:22 UTC (permalink / raw) --- doc/src/sgml/advanced.sgml | 52 ++++++++++++++++++++++++++++++++++ doc/src/sgml/func.sgml | 54 ++++++++++++++++++++++++++++++++++++ doc/src/sgml/ref/select.sgml | 38 +++++++++++++++++++++++-- 3 files changed, 142 insertions(+), 2 deletions(-) diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml index 755c9f1485..eda3612822 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> + Row pattern common syntax 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, max(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 24ad87f910..9c99dda4ae 100644 --- a/doc/src/sgml/func.sgml +++ b/doc/src/sgml/func.sgml @@ -21780,6 +21780,7 @@ SELECT count(*) FROM sometable; returns <literal>NULL</literal> if there is no such row. </para></entry> </row> + </tbody> </tgroup> </table> @@ -21819,6 +21820,59 @@ 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..8d3becd57a 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 +1074,40 @@ 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(Tue_Sep_12_15_18_43_2023_359)-- Content-Type: Text/X-Patch; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="v6-0006-Row-pattern-recognition-patch-tests.patch" ^ permalink raw reply [nested|flat] 2+ messages in thread
end of thread, other threads:[~2023-09-12 05:22 UTC | newest] Thread overview: 2+ messages (download: mbox mbox.gz follow: Atom feed) -- links below jump to the message on this page -- 2021-01-13 06:52 [PATCH] Fix misuses of RelationNeedsWAL Kyotaro Horiguchi <[email protected]> 2023-09-12 05:22 [PATCH v6 5/7] Row pattern recognition patch (docs). Tatsuo Ishii <[email protected]>
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