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authorPeter Eisentraut2021-02-27 07:11:14 +0000
committerPeter Eisentraut2021-02-27 07:13:24 +0000
commitf4adc41c4f92cc91d507b19e397140c35bb9fd71 (patch)
tree387b6ecdd5e9b4547d887b73f01689aa954f177d
parent4e90052c46c7751779ed83627676ed5e74ebe6d4 (diff)
Enhanced cycle mark values
Per SQL:202x draft, in the CYCLE clause of a recursive query, the cycle mark values can be of type boolean and can be omitted, in which case they default to TRUE and FALSE. Reviewed-by: Vik Fearing <[email protected]> Discussion: https://www.postgresql.org/message-id/flat/[email protected]
-rw-r--r--doc/src/sgml/queries.sgml5
-rw-r--r--doc/src/sgml/ref/select.sgml8
-rw-r--r--src/backend/catalog/sql_features.txt1
-rw-r--r--src/backend/parser/gram.y11
-rw-r--r--src/backend/utils/adt/ruleutils.c19
-rw-r--r--src/test/regress/expected/with.out117
-rw-r--r--src/test/regress/sql/with.sql30
7 files changed, 144 insertions, 47 deletions
diff --git a/doc/src/sgml/queries.sgml b/doc/src/sgml/queries.sgml
index 4741506eb5..bc0b3cc9fe 100644
--- a/doc/src/sgml/queries.sgml
+++ b/doc/src/sgml/queries.sgml
@@ -2349,14 +2349,13 @@ WITH RECURSIVE search_graph(id, link, data, depth) AS (
SELECT g.id, g.link, g.data, sg.depth + 1
FROM graph g, search_graph sg
WHERE g.id = sg.link
-) <emphasis>CYCLE id SET is_cycle TO true DEFAULT false USING path</emphasis>
+) <emphasis>CYCLE id SET is_cycle USING path</emphasis>
SELECT * FROM search_graph;
</programlisting>
and it will be internally rewritten to the above form. The
<literal>CYCLE</literal> clause specifies first the list of columns to
track for cycle detection, then a column name that will show whether a
- cycle has been detected, then two values to use in that column for the yes
- and no cases, and finally the name of another column that will track the
+ cycle has been detected, and finally the name of another column that will track the
path. The cycle and path columns will implicitly be added to the output
rows of the CTE.
</para>
diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml
index eb8b524951..ab91105599 100644
--- a/doc/src/sgml/ref/select.sgml
+++ b/doc/src/sgml/ref/select.sgml
@@ -74,7 +74,7 @@ SELECT [ ALL | DISTINCT [ ON ( <replaceable class="parameter">expression</replac
<replaceable class="parameter">with_query_name</replaceable> [ ( <replaceable class="parameter">column_name</replaceable> [, ...] ) ] AS [ [ NOT ] MATERIALIZED ] ( <replaceable class="parameter">select</replaceable> | <replaceable class="parameter">values</replaceable> | <replaceable class="parameter">insert</replaceable> | <replaceable class="parameter">update</replaceable> | <replaceable class="parameter">delete</replaceable> )
[ SEARCH { BREADTH | DEPTH } FIRST BY <replaceable>column_name</replaceable> [, ...] SET <replaceable>search_seq_col_name</replaceable> ]
- [ CYCLE <replaceable>column_name</replaceable> [, ...] SET <replaceable>cycle_mark_col_name</replaceable> TO <replaceable>cycle_mark_value</replaceable> DEFAULT <replaceable>cycle_mark_default</replaceable> USING <replaceable>cycle_path_col_name</replaceable> ]
+ [ CYCLE <replaceable>column_name</replaceable> [, ...] SET <replaceable>cycle_mark_col_name</replaceable> [ TO <replaceable>cycle_mark_value</replaceable> DEFAULT <replaceable>cycle_mark_default</replaceable> ] USING <replaceable>cycle_path_col_name</replaceable> ]
TABLE [ ONLY ] <replaceable class="parameter">table_name</replaceable> [ * ]
</synopsis>
@@ -302,8 +302,10 @@ TABLE [ ONLY ] <replaceable class="parameter">table_name</replaceable> [ * ]
been detected. <replaceable>cycle_mark_value</replaceable> and
<replaceable>cycle_mark_default</replaceable> must be constants and they
must be coercible to a common data type, and the data type must have an
- inequality operator. (The SQL standard requires that they be character
- strings, but PostgreSQL does not require that.) Furthermore, a column
+ inequality operator. (The SQL standard requires that they be Boolean
+ constants or character strings, but PostgreSQL does not require that.) By
+ default, <literal>TRUE</literal> and <literal>FALSE</literal> (of type
+ <type>boolean</type>) are used. Furthermore, a column
named <replaceable>cycle_path_col_name</replaceable> will be added to the
result column list of the <literal>WITH</literal> query. This column is
used internally for tracking visited rows. See <xref
diff --git a/src/backend/catalog/sql_features.txt b/src/backend/catalog/sql_features.txt
index a24387c1e7..ab0895ce3c 100644
--- a/src/backend/catalog/sql_features.txt
+++ b/src/backend/catalog/sql_features.txt
@@ -425,6 +425,7 @@ T121 WITH (excluding RECURSIVE) in query expression YES
T122 WITH (excluding RECURSIVE) in subquery YES
T131 Recursive query YES
T132 Recursive query in subquery YES
+T133 Enhanced cycle mark values YES SQL:202x draft
T141 SIMILAR predicate YES
T151 DISTINCT predicate YES
T152 DISTINCT predicate with negation YES
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index dd72a9fc3c..652be0b96d 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -11442,6 +11442,17 @@ opt_cycle_clause:
n->location = @1;
$$ = (Node *) n;
}
+ | CYCLE columnList SET ColId USING ColId
+ {
+ CTECycleClause *n = makeNode(CTECycleClause);
+ n->cycle_col_list = $2;
+ n->cycle_mark_column = $4;
+ n->cycle_mark_value = makeBoolAConst(true, -1);
+ n->cycle_mark_default = makeBoolAConst(false, -1);
+ n->cycle_path_column = $6;
+ n->location = @1;
+ $$ = (Node *) n;
+ }
| /*EMPTY*/
{
$$ = NULL;
diff --git a/src/backend/utils/adt/ruleutils.c b/src/backend/utils/adt/ruleutils.c
index 4a9244f4f6..879288c139 100644
--- a/src/backend/utils/adt/ruleutils.c
+++ b/src/backend/utils/adt/ruleutils.c
@@ -5208,10 +5208,21 @@ get_with_clause(Query *query, deparse_context *context)
}
appendStringInfo(buf, " SET %s", quote_identifier(cte->cycle_clause->cycle_mark_column));
- appendStringInfoString(buf, " TO ");
- get_rule_expr(cte->cycle_clause->cycle_mark_value, context, false);
- appendStringInfoString(buf, " DEFAULT ");
- get_rule_expr(cte->cycle_clause->cycle_mark_default, context, false);
+
+ {
+ Const *cmv = castNode(Const, cte->cycle_clause->cycle_mark_value);
+ Const *cmd = castNode(Const, cte->cycle_clause->cycle_mark_default);
+
+ if (!(cmv->consttype == BOOLOID && !cmv->constisnull && DatumGetBool(cmv->constvalue) == true &&
+ cmd->consttype == BOOLOID && !cmd->constisnull && DatumGetBool(cmd->constvalue) == false))
+ {
+ appendStringInfoString(buf, " TO ");
+ get_rule_expr(cte->cycle_clause->cycle_mark_value, context, false);
+ appendStringInfoString(buf, " DEFAULT ");
+ get_rule_expr(cte->cycle_clause->cycle_mark_default, context, false);
+ }
+ }
+
appendStringInfo(buf, " USING %s", quote_identifier(cte->cycle_clause->cycle_path_column));
}
diff --git a/src/test/regress/expected/with.out b/src/test/regress/expected/with.out
index a7a652822c..9a6b716ddc 100644
--- a/src/test/regress/expected/with.out
+++ b/src/test/regress/expected/with.out
@@ -951,7 +951,7 @@ with recursive search_graph(f, t, label) as (
select g.*
from graph g, search_graph sg
where g.f = sg.t
-) cycle f, t set is_cycle to true default false using path
+) cycle f, t set is_cycle using path
select * from search_graph;
f | t | label | is_cycle | path
---+---+------------+----------+-------------------------------------------
@@ -1071,7 +1071,7 @@ with recursive a as (
select 1 as b
union all
select * from a
-) cycle b set c to true default false using p
+) cycle b set c using p
select * from a;
b | c | p
---+---+-----------
@@ -1087,7 +1087,7 @@ with recursive search_graph(f, t, label) as (
from graph g, search_graph sg
where g.f = sg.t
) search depth first by f, t set seq
- cycle f, t set is_cycle to true default false using path
+ cycle f, t set is_cycle using path
select * from search_graph;
f | t | label | seq | is_cycle | path
---+---+------------+-------------------------------------------+----------+-------------------------------------------
@@ -1125,7 +1125,7 @@ with recursive search_graph(f, t, label) as (
from graph g, search_graph sg
where g.f = sg.t
) search breadth first by f, t set seq
- cycle f, t set is_cycle to true default false using path
+ cycle f, t set is_cycle using path
select * from search_graph;
f | t | label | seq | is_cycle | path
---+---+------------+---------+----------+-------------------------------------------
@@ -1163,10 +1163,10 @@ with recursive search_graph(f, t, label) as (
select g.*
from graph g, search_graph sg
where g.f = sg.t
-) cycle foo, tar set is_cycle to true default false using path
+) cycle foo, tar set is_cycle using path
select * from search_graph;
ERROR: cycle column "foo" not in WITH query column list
-LINE 7: ) cycle foo, tar set is_cycle to true default false using pa...
+LINE 7: ) cycle foo, tar set is_cycle using path
^
with recursive search_graph(f, t, label) as (
select * from graph g
@@ -1257,38 +1257,99 @@ ERROR: search_sequence column name and cycle path column name are the same
LINE 7: ) search depth first by f, t set foo
^
-- test ruleutils and view expansion
-create temp view v_cycle as
+create temp view v_cycle1 as
with recursive search_graph(f, t, label) as (
select * from graph g
union all
select g.*
from graph g, search_graph sg
where g.f = sg.t
-) cycle f, t set is_cycle to true default false using path
+) cycle f, t set is_cycle using path
select f, t, label from search_graph;
-select pg_get_viewdef('v_cycle');
- pg_get_viewdef
---------------------------------------------------------------------
- WITH RECURSIVE search_graph(f, t, label) AS ( +
- SELECT g.f, +
- g.t, +
- g.label +
- FROM graph g +
- UNION ALL +
- SELECT g.f, +
- g.t, +
- g.label +
- FROM graph g, +
- search_graph sg +
- WHERE (g.f = sg.t) +
- ) CYCLE f, t SET is_cycle TO true DEFAULT false USING path+
- SELECT search_graph.f, +
- search_graph.t, +
- search_graph.label +
+create temp view v_cycle2 as
+with recursive search_graph(f, t, label) as (
+ select * from graph g
+ union all
+ select g.*
+ from graph g, search_graph sg
+ where g.f = sg.t
+) cycle f, t set is_cycle to 'Y' default 'N' using path
+select f, t, label from search_graph;
+select pg_get_viewdef('v_cycle1');
+ pg_get_viewdef
+------------------------------------------------
+ WITH RECURSIVE search_graph(f, t, label) AS (+
+ SELECT g.f, +
+ g.t, +
+ g.label +
+ FROM graph g +
+ UNION ALL +
+ SELECT g.f, +
+ g.t, +
+ g.label +
+ FROM graph g, +
+ search_graph sg +
+ WHERE (g.f = sg.t) +
+ ) CYCLE f, t SET is_cycle USING path +
+ SELECT search_graph.f, +
+ search_graph.t, +
+ search_graph.label +
FROM search_graph;
(1 row)
-select * from v_cycle;
+select pg_get_viewdef('v_cycle2');
+ pg_get_viewdef
+-----------------------------------------------------------------------------
+ WITH RECURSIVE search_graph(f, t, label) AS ( +
+ SELECT g.f, +
+ g.t, +
+ g.label +
+ FROM graph g +
+ UNION ALL +
+ SELECT g.f, +
+ g.t, +
+ g.label +
+ FROM graph g, +
+ search_graph sg +
+ WHERE (g.f = sg.t) +
+ ) CYCLE f, t SET is_cycle TO 'Y'::text DEFAULT 'N'::text USING path+
+ SELECT search_graph.f, +
+ search_graph.t, +
+ search_graph.label +
+ FROM search_graph;
+(1 row)
+
+select * from v_cycle1;
+ f | t | label
+---+---+------------
+ 1 | 2 | arc 1 -> 2
+ 1 | 3 | arc 1 -> 3
+ 2 | 3 | arc 2 -> 3
+ 1 | 4 | arc 1 -> 4
+ 4 | 5 | arc 4 -> 5
+ 5 | 1 | arc 5 -> 1
+ 1 | 2 | arc 1 -> 2
+ 1 | 3 | arc 1 -> 3
+ 1 | 4 | arc 1 -> 4
+ 2 | 3 | arc 2 -> 3
+ 4 | 5 | arc 4 -> 5
+ 5 | 1 | arc 5 -> 1
+ 1 | 2 | arc 1 -> 2
+ 1 | 3 | arc 1 -> 3
+ 1 | 4 | arc 1 -> 4
+ 2 | 3 | arc 2 -> 3
+ 4 | 5 | arc 4 -> 5
+ 5 | 1 | arc 5 -> 1
+ 1 | 2 | arc 1 -> 2
+ 1 | 3 | arc 1 -> 3
+ 1 | 4 | arc 1 -> 4
+ 2 | 3 | arc 2 -> 3
+ 4 | 5 | arc 4 -> 5
+ 5 | 1 | arc 5 -> 1
+ 2 | 3 | arc 2 -> 3
+(25 rows)
+
+select * from v_cycle2;
f | t | label
---+---+------------
1 | 2 | arc 1 -> 2
diff --git a/src/test/regress/sql/with.sql b/src/test/regress/sql/with.sql
index 85a671c630..1a9bdc9f3e 100644
--- a/src/test/regress/sql/with.sql
+++ b/src/test/regress/sql/with.sql
@@ -509,7 +509,7 @@ with recursive search_graph(f, t, label) as (
select g.*
from graph g, search_graph sg
where g.f = sg.t
-) cycle f, t set is_cycle to true default false using path
+) cycle f, t set is_cycle using path
select * from search_graph;
with recursive search_graph(f, t, label) as (
@@ -545,7 +545,7 @@ with recursive a as (
select 1 as b
union all
select * from a
-) cycle b set c to true default false using p
+) cycle b set c using p
select * from a;
-- search+cycle
@@ -556,7 +556,7 @@ with recursive search_graph(f, t, label) as (
from graph g, search_graph sg
where g.f = sg.t
) search depth first by f, t set seq
- cycle f, t set is_cycle to true default false using path
+ cycle f, t set is_cycle using path
select * from search_graph;
with recursive search_graph(f, t, label) as (
@@ -566,7 +566,7 @@ with recursive search_graph(f, t, label) as (
from graph g, search_graph sg
where g.f = sg.t
) search breadth first by f, t set seq
- cycle f, t set is_cycle to true default false using path
+ cycle f, t set is_cycle using path
select * from search_graph;
-- various syntax errors
@@ -576,7 +576,7 @@ with recursive search_graph(f, t, label) as (
select g.*
from graph g, search_graph sg
where g.f = sg.t
-) cycle foo, tar set is_cycle to true default false using path
+) cycle foo, tar set is_cycle using path
select * from search_graph;
with recursive search_graph(f, t, label) as (
@@ -654,19 +654,31 @@ with recursive search_graph(f, t, label) as (
select * from search_graph;
-- test ruleutils and view expansion
-create temp view v_cycle as
+create temp view v_cycle1 as
with recursive search_graph(f, t, label) as (
select * from graph g
union all
select g.*
from graph g, search_graph sg
where g.f = sg.t
-) cycle f, t set is_cycle to true default false using path
+) cycle f, t set is_cycle using path
+select f, t, label from search_graph;
+
+create temp view v_cycle2 as
+with recursive search_graph(f, t, label) as (
+ select * from graph g
+ union all
+ select g.*
+ from graph g, search_graph sg
+ where g.f = sg.t
+) cycle f, t set is_cycle to 'Y' default 'N' using path
select f, t, label from search_graph;
-select pg_get_viewdef('v_cycle');
+select pg_get_viewdef('v_cycle1');
+select pg_get_viewdef('v_cycle2');
-select * from v_cycle;
+select * from v_cycle1;
+select * from v_cycle2;
--
-- test multiple WITH queries