From 4b36e81def50be44bd1f68247e33a22343520b5e Mon Sep 17 00:00:00 2001 From: Peter Eisentraut Date: Fri, 9 Oct 2020 11:32:10 +0200 Subject: [PATCH v3] SEARCH and CYCLE clauses Discussion: https://www.postgresql.org/message-id/flat/db80ceee-6f97-9b4a-8ee8-3ba0c58e5be2@2ndquadrant.com --- doc/src/sgml/queries.sgml | 213 ++++++- doc/src/sgml/ref/select.sgml | 44 ++ src/backend/nodes/copyfuncs.c | 39 ++ src/backend/nodes/equalfuncs.c | 35 ++ src/backend/nodes/nodeFuncs.c | 6 + src/backend/nodes/outfuncs.c | 35 ++ src/backend/nodes/readfuncs.c | 43 ++ src/backend/parser/analyze.c | 47 +- src/backend/parser/gram.y | 58 +- src/backend/parser/parse_agg.c | 7 + src/backend/parser/parse_cte.c | 117 ++++ src/backend/parser/parse_expr.c | 4 + src/backend/parser/parse_func.c | 3 + src/backend/parser/parse_relation.c | 54 +- src/backend/parser/parse_target.c | 21 +- src/backend/rewrite/Makefile | 1 + src/backend/rewrite/rewriteHandler.c | 18 + src/backend/rewrite/rewriteSearchCycle.c | 709 +++++++++++++++++++++++ src/backend/utils/adt/ruleutils.c | 47 ++ src/include/nodes/nodes.h | 2 + src/include/nodes/parsenodes.h | 28 +- src/include/parser/analyze.h | 2 + src/include/parser/kwlist.h | 2 + src/include/parser/parse_node.h | 2 + src/include/rewrite/rewriteSearchCycle.h | 21 + src/test/regress/expected/with.out | 433 ++++++++++++++ src/test/regress/sql/with.sql | 210 +++++++ 27 files changed, 2153 insertions(+), 48 deletions(-) create mode 100644 src/backend/rewrite/rewriteSearchCycle.c create mode 100644 src/include/rewrite/rewriteSearchCycle.h diff --git a/doc/src/sgml/queries.sgml b/doc/src/sgml/queries.sgml index 77fb1991ae..34b3e48986 100644 --- a/doc/src/sgml/queries.sgml +++ b/doc/src/sgml/queries.sgml @@ -2011,6 +2011,10 @@ <command>SELECT</command> in <literal>WITH</literal> but we'd have needed two levels of nested sub-SELECTs. It's a bit easier to follow this way. + + + + Recursive Queries @@ -2114,6 +2118,153 @@ Recursive Query Evaluation + + Search Order + + + When computing a tree traversal using a recursive query, you might want to + order the results in either depth-first or breadth-first order. This can + be done by computing an ordering column alongside the other data columns + and using that to sort the results at the end. Note that this does not + actually control in which order the query evaluation visits the rows; that + is as always in SQL implementation-dependent. This approach merely + provides a convenient way to order the results afterwards. + + + + To create a depth-first order, we compute for each result row an array of + rows that we have visited so far. For example, consider the following + query that searches a table tree using a + link field: + + +WITH RECURSIVE search_tree(id, link, data) AS ( + SELECT t.id, t.link, t.data + FROM tree t + UNION ALL + SELECT t.id, t.link, t.data + FROM tree t, search_tree st + WHERE t.id = st.link +) +SELECT * FROM search_tree; + + + To add depth-first ordering information, you can write this: + + +WITH RECURSIVE search_tree(id, link, data, path) AS ( + SELECT t.id, t.link, t.data, ARRAY[t.id] + FROM tree t + UNION ALL + SELECT t.id, t.link, t.data, path || t.id + FROM tree t, search_tree st + WHERE t.id = st.link +) +SELECT * FROM search_tree ORDER BY path; + + + + + In the general case where more than one field needs to be used to identify + a row, use an array of rows. For example, if we needed to track fields + f1 and f2: + + +WITH RECURSIVE search_tree(id, link, data, path) AS ( + SELECT t.id, t.link, t.data, ARRAY[ROW(t.f1, t.f2)] + FROM tree t + UNION ALL + SELECT t.id, t.link, t.data, path || ROW(t.f1, t.f2) + FROM tree t, search_tree st + WHERE t.id = st.link +) +SELECT * FROM search_tree ORDER BY path; + + + + + + The queries shown in this and the following section involving (explicit + or implicit) ROW constructors in the target list only + support UNION ALL (not plain UNION) + in the current implementation. + + + + + + Omit the ROW() syntax in the common case where only one + field needs to be tracked. This allows a simple array rather than a + composite-type array to be used, gaining efficiency. + + + + + To create a breadth-first order, you can add a column that tracks the depth + of the search, for example: + + +WITH RECURSIVE search_tree(id, link, data, level) AS ( + SELECT t.id, t.link, t.data, 0 + FROM tree t + UNION ALL + SELECT t.id, t.link, t.data, level + 1 + FROM tree t, search_tree st + WHERE t.id = st.link +) +SELECT * FROM search_tree ORDER BY level; + + + To get a stable sort, add data columns as secondary sorting columns. + + + + + The recursive query evaluation algorithm produces its output in + breadth-first search order. However, this is an implementation detail and + it is perhaps unsound to rely on it. The order of the rows within each + level is certainly undefined, so some explicit ordering might be desired + in any case. + + + + + There is built-in syntax to compute a depth- or breadth-first sort column. + For example: + + +WITH RECURSIVE search_tree(id, link, data) AS ( + SELECT t.id, t.link, t.data + FROM tree t + UNION ALL + SELECT t.id, t.link, t.data + FROM tree t, search_tree st + WHERE t.id = st.link +) SEARCH DEPTH FIRST BY id SET ordercol +SELECT * FROM search_tree ORDER BY ordercol; + +WITH RECURSIVE search_tree(id, link, data) AS ( + SELECT t.id, t.link, t.data + FROM tree t + UNION ALL + SELECT t.id, t.link, t.data + FROM tree t, search_tree st + WHERE t.id = st.link +) SEARCH BREADTH FIRST BY id SET ordercol +SELECT * FROM search_tree ORDER BY ordercol; + + This syntax is internally expanded to something similar to the above + hand-written forms. The SEARCH clause specifies whether + depth- or breadth first search is wanted, the list of columns to track for + sorting, and a column name that will contain the result data that can be + used for sorting. That column will implicitly be added to the output rows + of the CTE. + + + + + Cycle Detection + When working with recursive queries it is important to be sure that the recursive part of the query will eventually return no tuples, @@ -2144,18 +2295,18 @@ Recursive Query Evaluation UNION ALL to UNION would not eliminate the looping. Instead we need to recognize whether we have reached the same row again while following a particular path of links. We add two columns - path and cycle to the loop-prone query: + is_cycle and path to the loop-prone query: -WITH RECURSIVE search_graph(id, link, data, depth, path, cycle) AS ( +WITH RECURSIVE search_graph(id, link, data, depth, is_cycle, path) AS ( SELECT g.id, g.link, g.data, 1, - ARRAY[g.id], - false + false, + ARRAY[g.id] FROM graph g UNION ALL SELECT g.id, g.link, g.data, sg.depth + 1, - path || g.id, - g.id = ANY(path) + g.id = ANY(path), + path || g.id FROM graph g, search_graph sg WHERE g.id = sg.link AND NOT cycle ) @@ -2172,15 +2323,15 @@ Recursive Query Evaluation compare fields f1 and f2: -WITH RECURSIVE search_graph(id, link, data, depth, path, cycle) AS ( +WITH RECURSIVE search_graph(id, link, data, depth, is_cycle, path) AS ( SELECT g.id, g.link, g.data, 1, - ARRAY[ROW(g.f1, g.f2)], - false + false, + ARRAY[ROW(g.f1, g.f2)] FROM graph g UNION ALL SELECT g.id, g.link, g.data, sg.depth + 1, - path || ROW(g.f1, g.f2), - ROW(g.f1, g.f2) = ANY(path) + ROW(g.f1, g.f2) = ANY(path), + path || ROW(g.f1, g.f2) FROM graph g, search_graph sg WHERE g.id = sg.link AND NOT cycle ) @@ -2196,12 +2347,39 @@ Recursive Query Evaluation + + There is built-in syntax to simplify cycle detection. The above query can + also be written like this: + +WITH RECURSIVE search_graph(id, link, data, depth) AS ( + SELECT g.id, g.link, g.data, 1 + FROM graph g + UNION ALL + SELECT g.id, g.link, g.data, sg.depth + 1 + FROM graph g, search_graph sg + WHERE g.id = sg.link +) CYCLE id SET is_cycle TO true DEFAULT false USING path +SELECT * FROM search_graph; + + and it will be internally rewritten to the above form. The + CYCLE 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 + path. The cycle and path columns will implicitly be added to the output + rows of the CTE. + + - The recursive query evaluation algorithm produces its output in - breadth-first search order. You can display the results in depth-first - search order by making the outer query ORDER BY a - path column constructed in this way. + The cycle path column is computed in the same way as the depth-first + ordering column show in the previous section. A query can have both a + SEARCH and a CYCLE clause, but a + depth-first search specification and a cycle detection specification would + create redundant computations, so it's more efficient to just use the + CYCLE clause and order by the path column. If + breadth-first ordering is wanted, then specifying both + SEARCH and CYCLE can be useful. @@ -2229,6 +2407,11 @@ Recursive Query Evaluation outer query will usually try to fetch all of the WITH query's output anyway. + + + + + Common Table Expression Materialization A useful property of WITH queries is that they are diff --git a/doc/src/sgml/ref/select.sgml b/doc/src/sgml/ref/select.sgml index b4dea9b6ac..7b79c6fe91 100644 --- a/doc/src/sgml/ref/select.sgml +++ b/doc/src/sgml/ref/select.sgml @@ -73,6 +73,8 @@ and with_query is: with_query_name [ ( column_name [, ...] ) ] AS [ [ NOT ] MATERIALIZED ] ( select | values | insert | update | delete ) + [ SEARCH { BREADTH | DEPTH } FIRST BY column_name [, ...] SET search_seq_col_name ] + [ CYCLE column_name [, ...] SET cycle_mark_col_name TO cycle_mark_value DEFAULT cycle_mark_default USING cycle_path_col_name ] TABLE [ ONLY ] table_name [ * ] @@ -276,6 +278,48 @@ <literal>WITH</literal> Clause queries that do not use recursion or forward references. + + The optional SEARCH clause computes a search + sequence column that can be used for ordering the results of a + recursive query in either breadth-first or depth-first order. The + supplied column name list specifies the row key that is to be used for + keeping track of visited rows. A column named + search_seq_col_name will be added to the result + column list of the WITH query. This column can be + ordered by in the outer query to achieve the respective ordering. See + for examples. + + + + The optional CYCLE clause is used to detect cycles in + recursive queries. The supplied column name list specifies the row key + that is to be used for keeping track of visited rows. A column named + cycle_mark_col_name will be added to the result + column list of the WITH query. This column will be set + to cycle_mark_value when a cycle has been + detected, else to cycle_mark_default. + Furthermore, processing of the recursive union will stop when a cycle has + been detected. cycle_mark_value and + cycle_mark_default 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 + named cycle_path_col_name will be added to the + result column list of the WITH query. This column is + used internally for tracking visited rows. See for examples. + + + + Both the SEARCH and the CYCLE clause + are only valid for recursive WITH queries. The current + implementation only supports recursive queries using UNION + ALL (not plain UNION or equivalently + UNION DISTINCT). If both clauses are used, the column + added by the SEARCH clause appears before the columns + added by the CYCLE clause. + + The primary query and the WITH queries are all (notionally) executed at the same time. This implies that the effects of diff --git a/src/backend/nodes/copyfuncs.c b/src/backend/nodes/copyfuncs.c index 0409a40b82..ed40d77a9d 100644 --- a/src/backend/nodes/copyfuncs.c +++ b/src/backend/nodes/copyfuncs.c @@ -2588,6 +2588,37 @@ _copyOnConflictClause(const OnConflictClause *from) return newnode; } +static CTESearchClause * +_copyCTESearchClause(const CTESearchClause *from) +{ + CTESearchClause *newnode = makeNode(CTESearchClause); + + COPY_NODE_FIELD(search_col_list); + COPY_SCALAR_FIELD(search_breadth_first); + COPY_STRING_FIELD(search_seq_column); + COPY_LOCATION_FIELD(location); + + return newnode; +} + +static CTECycleClause * +_copyCTECycleClause(const CTECycleClause *from) +{ + CTECycleClause *newnode = makeNode(CTECycleClause); + + COPY_NODE_FIELD(cycle_col_list); + COPY_STRING_FIELD(cycle_mark_column); + COPY_NODE_FIELD(cycle_mark_value); + COPY_NODE_FIELD(cycle_mark_default); + COPY_SCALAR_FIELD(cycle_mark_type); + COPY_SCALAR_FIELD(cycle_mark_typmod); + COPY_SCALAR_FIELD(cycle_mark_collation); + COPY_STRING_FIELD(cycle_path_column); + COPY_LOCATION_FIELD(location); + + return newnode; +} + static CommonTableExpr * _copyCommonTableExpr(const CommonTableExpr *from) { @@ -2604,6 +2635,8 @@ _copyCommonTableExpr(const CommonTableExpr *from) COPY_NODE_FIELD(ctecoltypes); COPY_NODE_FIELD(ctecoltypmods); COPY_NODE_FIELD(ctecolcollations); + COPY_NODE_FIELD(search_clause); + COPY_NODE_FIELD(cycle_clause); return newnode; } @@ -5672,6 +5705,12 @@ copyObjectImpl(const void *from) case T_OnConflictClause: retval = _copyOnConflictClause(from); break; + case T_CTESearchClause: + retval = _copyCTESearchClause(from); + break; + case T_CTECycleClause: + retval = _copyCTECycleClause(from); + break; case T_CommonTableExpr: retval = _copyCommonTableExpr(from); break; diff --git a/src/backend/nodes/equalfuncs.c b/src/backend/nodes/equalfuncs.c index e2d1b987bf..6bacee3882 100644 --- a/src/backend/nodes/equalfuncs.c +++ b/src/backend/nodes/equalfuncs.c @@ -2830,6 +2830,33 @@ _equalOnConflictClause(const OnConflictClause *a, const OnConflictClause *b) return true; } +static bool +_equalCTESearchClause(const CTESearchClause *a, const CTESearchClause *b) +{ + COMPARE_NODE_FIELD(search_col_list); + COMPARE_SCALAR_FIELD(search_breadth_first); + COMPARE_STRING_FIELD(search_seq_column); + COMPARE_LOCATION_FIELD(location); + + return true; +} + +static bool +_equalCTECycleClause(const CTECycleClause *a, const CTECycleClause *b) +{ + COMPARE_NODE_FIELD(cycle_col_list); + COMPARE_STRING_FIELD(cycle_mark_column); + COMPARE_NODE_FIELD(cycle_mark_value); + COMPARE_NODE_FIELD(cycle_mark_default); + COMPARE_SCALAR_FIELD(cycle_mark_type); + COMPARE_SCALAR_FIELD(cycle_mark_typmod); + COMPARE_SCALAR_FIELD(cycle_mark_collation); + COMPARE_STRING_FIELD(cycle_path_column); + COMPARE_LOCATION_FIELD(location); + + return true; +} + static bool _equalCommonTableExpr(const CommonTableExpr *a, const CommonTableExpr *b) { @@ -2844,6 +2871,8 @@ _equalCommonTableExpr(const CommonTableExpr *a, const CommonTableExpr *b) COMPARE_NODE_FIELD(ctecoltypes); COMPARE_NODE_FIELD(ctecoltypmods); COMPARE_NODE_FIELD(ctecolcollations); + COMPARE_NODE_FIELD(search_clause); + COMPARE_NODE_FIELD(cycle_clause); return true; } @@ -3724,6 +3753,12 @@ equal(const void *a, const void *b) case T_OnConflictClause: retval = _equalOnConflictClause(a, b); break; + case T_CTESearchClause: + retval = _equalCTESearchClause(a, b); + break; + case T_CTECycleClause: + retval = _equalCTECycleClause(a, b); + break; case T_CommonTableExpr: retval = _equalCommonTableExpr(a, b); break; diff --git a/src/backend/nodes/nodeFuncs.c b/src/backend/nodes/nodeFuncs.c index 1dc873ed25..abd632a1b4 100644 --- a/src/backend/nodes/nodeFuncs.c +++ b/src/backend/nodes/nodeFuncs.c @@ -1575,6 +1575,12 @@ exprLocation(const Node *expr) case T_OnConflictClause: loc = ((const OnConflictClause *) expr)->location; break; + case T_CTESearchClause: + loc = ((const CTESearchClause *) expr)->location; + break; + case T_CTECycleClause: + loc = ((const CTECycleClause *) expr)->location; + break; case T_CommonTableExpr: loc = ((const CommonTableExpr *) expr)->location; break; diff --git a/src/backend/nodes/outfuncs.c b/src/backend/nodes/outfuncs.c index f0386480ab..e88aa74231 100644 --- a/src/backend/nodes/outfuncs.c +++ b/src/backend/nodes/outfuncs.c @@ -3047,6 +3047,33 @@ _outWithClause(StringInfo str, const WithClause *node) WRITE_LOCATION_FIELD(location); } +static void +_outCTESearchClause(StringInfo str, const CTESearchClause *node) +{ + WRITE_NODE_TYPE("CTESEARCHCLAUSE"); + + WRITE_NODE_FIELD(search_col_list); + WRITE_BOOL_FIELD(search_breadth_first); + WRITE_STRING_FIELD(search_seq_column); + WRITE_LOCATION_FIELD(location); +} + +static void +_outCTECycleClause(StringInfo str, const CTECycleClause *node) +{ + WRITE_NODE_TYPE("CTECYCLECLAUSE"); + + WRITE_NODE_FIELD(cycle_col_list); + WRITE_STRING_FIELD(cycle_mark_column); + WRITE_NODE_FIELD(cycle_mark_value); + WRITE_NODE_FIELD(cycle_mark_default); + WRITE_OID_FIELD(cycle_mark_type); + WRITE_INT_FIELD(cycle_mark_typmod); + WRITE_OID_FIELD(cycle_mark_collation); + WRITE_STRING_FIELD(cycle_path_column); + WRITE_LOCATION_FIELD(location); +} + static void _outCommonTableExpr(StringInfo str, const CommonTableExpr *node) { @@ -3063,6 +3090,8 @@ _outCommonTableExpr(StringInfo str, const CommonTableExpr *node) WRITE_NODE_FIELD(ctecoltypes); WRITE_NODE_FIELD(ctecoltypmods); WRITE_NODE_FIELD(ctecolcollations); + WRITE_NODE_FIELD(search_clause); + WRITE_NODE_FIELD(cycle_clause); } static void @@ -4233,6 +4262,12 @@ outNode(StringInfo str, const void *obj) case T_WithClause: _outWithClause(str, obj); break; + case T_CTESearchClause: + _outCTESearchClause(str, obj); + break; + case T_CTECycleClause: + _outCTECycleClause(str, obj); + break; case T_CommonTableExpr: _outCommonTableExpr(str, obj); break; diff --git a/src/backend/nodes/readfuncs.c b/src/backend/nodes/readfuncs.c index 42050ab719..43f88d6c94 100644 --- a/src/backend/nodes/readfuncs.c +++ b/src/backend/nodes/readfuncs.c @@ -409,6 +409,43 @@ _readRowMarkClause(void) READ_DONE(); } +/* + * _readCTESearchClause + */ +static CTESearchClause * +_readCTESearchClause(void) +{ + READ_LOCALS(CTESearchClause); + + READ_NODE_FIELD(search_col_list); + READ_BOOL_FIELD(search_breadth_first); + READ_STRING_FIELD(search_seq_column); + READ_LOCATION_FIELD(location); + + READ_DONE(); +} + +/* + * _readCTECycleClause + */ +static CTECycleClause * +_readCTECycleClause(void) +{ + READ_LOCALS(CTECycleClause); + + READ_NODE_FIELD(cycle_col_list); + READ_STRING_FIELD(cycle_mark_column); + READ_NODE_FIELD(cycle_mark_value); + READ_NODE_FIELD(cycle_mark_default); + READ_OID_FIELD(cycle_mark_type); + READ_INT_FIELD(cycle_mark_typmod); + READ_OID_FIELD(cycle_mark_collation); + READ_STRING_FIELD(cycle_path_column); + READ_LOCATION_FIELD(location); + + READ_DONE(); +} + /* * _readCommonTableExpr */ @@ -428,6 +465,8 @@ _readCommonTableExpr(void) READ_NODE_FIELD(ctecoltypes); READ_NODE_FIELD(ctecoltypmods); READ_NODE_FIELD(ctecolcollations); + READ_NODE_FIELD(search_clause); + READ_NODE_FIELD(cycle_clause); READ_DONE(); } @@ -2652,6 +2691,10 @@ parseNodeString(void) return_value = _readWindowClause(); else if (MATCH("ROWMARKCLAUSE", 13)) return_value = _readRowMarkClause(); + else if (MATCH("CTESEARCHCLAUSE", 15)) + return_value = _readCTESearchClause(); + else if (MATCH("CTECYCLECLAUSE", 14)) + return_value = _readCTECycleClause(); else if (MATCH("COMMONTABLEEXPR", 15)) return_value = _readCommonTableExpr(); else if (MATCH("SETOPERATIONSTMT", 16)) diff --git a/src/backend/parser/analyze.c b/src/backend/parser/analyze.c index c159fb2957..96026ab669 100644 --- a/src/backend/parser/analyze.c +++ b/src/backend/parser/analyze.c @@ -1811,6 +1811,33 @@ transformSetOperationStmt(ParseState *pstate, SelectStmt *stmt) return qry; } +/* + * Make a SortGroupClause node for a SetOperationStmt's groupClauses + */ +SortGroupClause * +makeSortGroupClauseForSetOp(Oid rescoltype) +{ + SortGroupClause *grpcl = makeNode(SortGroupClause); + Oid sortop; + Oid eqop; + bool hashable; + + /* determine the eqop and optional sortop */ + get_sort_group_operators(rescoltype, + false, true, false, + &sortop, &eqop, NULL, + &hashable); + + /* we don't have a tlist yet, so can't assign sortgrouprefs */ + grpcl->tleSortGroupRef = 0; + grpcl->eqop = eqop; + grpcl->sortop = sortop; + grpcl->nulls_first = false; /* OK with or without sortop */ + grpcl->hashable = hashable; + + return grpcl; +} + /* * transformSetOperationTree * Recursively transform leaves and internal nodes of a set-op tree @@ -2114,31 +2141,15 @@ transformSetOperationTree(ParseState *pstate, SelectStmt *stmt, */ if (op->op != SETOP_UNION || !op->all) { - SortGroupClause *grpcl = makeNode(SortGroupClause); - Oid sortop; - Oid eqop; - bool hashable; ParseCallbackState pcbstate; setup_parser_errposition_callback(&pcbstate, pstate, bestlocation); - /* determine the eqop and optional sortop */ - get_sort_group_operators(rescoltype, - false, true, false, - &sortop, &eqop, NULL, - &hashable); + op->groupClauses = lappend(op->groupClauses, + makeSortGroupClauseForSetOp(rescoltype)); cancel_parser_errposition_callback(&pcbstate); - - /* we don't have a tlist yet, so can't assign sortgrouprefs */ - grpcl->tleSortGroupRef = 0; - grpcl->eqop = eqop; - grpcl->sortop = sortop; - grpcl->nulls_first = false; /* OK with or without sortop */ - grpcl->hashable = hashable; - - op->groupClauses = lappend(op->groupClauses, grpcl); } /* diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y index 480d168346..164dad0b89 100644 --- a/src/backend/parser/gram.y +++ b/src/backend/parser/gram.y @@ -495,6 +495,7 @@ static Node *makeRecursiveViewSelect(char *relname, List *aliases, Node *query); %type row explicit_row implicit_row type_list array_expr_list %type case_expr case_arg when_clause case_default %type when_clause_list +%type opt_search_clause opt_cycle_clause %type sub_type opt_materialized %type NumericOnly %type NumericOnly_list @@ -631,7 +632,7 @@ static Node *makeRecursiveViewSelect(char *relname, List *aliases, Node *query); ASSERTION ASSIGNMENT ASYMMETRIC AT ATTACH ATTRIBUTE AUTHORIZATION BACKWARD BEFORE BEGIN_P BETWEEN BIGINT BINARY BIT - BOOLEAN_P BOTH BY + BOOLEAN_P BOTH BREADTH BY CACHE CALL CALLED CASCADE CASCADED CASE CAST CATALOG_P CHAIN CHAR_P CHARACTER CHARACTERISTICS CHECK CHECKPOINT CLASS CLOSE @@ -643,7 +644,7 @@ static Node *makeRecursiveViewSelect(char *relname, List *aliases, Node *query); CURRENT_TIME CURRENT_TIMESTAMP CURRENT_USER CURSOR CYCLE DATA_P DATABASE DAY_P DEALLOCATE DEC DECIMAL_P DECLARE DEFAULT DEFAULTS - DEFERRABLE DEFERRED DEFINER DELETE_P DELIMITER DELIMITERS DEPENDS DESC + DEFERRABLE DEFERRED DEFINER DELETE_P DELIMITER DELIMITERS DEPENDS DEPTH DESC DETACH DICTIONARY DISABLE_P DISCARD DISTINCT DO DOCUMENT_P DOMAIN_P DOUBLE_P DROP @@ -11340,8 +11341,6 @@ simple_select: * WITH [ RECURSIVE ] [ (,...) ] * AS (query) [ SEARCH or CYCLE clause ] * - * We don't currently support the SEARCH or CYCLE clause. - * * Recognizing WITH_LA here allows a CTE to be named TIME or ORDINALITY. */ with_clause: @@ -11373,13 +11372,15 @@ cte_list: | cte_list ',' common_table_expr { $$ = lappend($1, $3); } ; -common_table_expr: name opt_name_list AS opt_materialized '(' PreparableStmt ')' +common_table_expr: name opt_name_list AS opt_materialized '(' PreparableStmt ')' opt_search_clause opt_cycle_clause { CommonTableExpr *n = makeNode(CommonTableExpr); n->ctename = $1; n->aliascolnames = $2; n->ctematerialized = $4; n->ctequery = $6; + n->search_clause = castNode(CTESearchClause, $8); + n->cycle_clause = castNode(CTECycleClause, $9); n->location = @1; $$ = (Node *) n; } @@ -11391,6 +11392,49 @@ opt_materialized: | /*EMPTY*/ { $$ = CTEMaterializeDefault; } ; +opt_search_clause: + SEARCH DEPTH FIRST_P BY columnList SET ColId + { + CTESearchClause *n = makeNode(CTESearchClause); + n->search_col_list = $5; + n->search_breadth_first = false; + n->search_seq_column = $7; + n->location = @1; + $$ = (Node *) n; + } + | SEARCH BREADTH FIRST_P BY columnList SET ColId + { + CTESearchClause *n = makeNode(CTESearchClause); + n->search_col_list = $5; + n->search_breadth_first = true; + n->search_seq_column = $7; + n->location = @1; + $$ = (Node *) n; + } + | /*EMPTY*/ + { + $$ = NULL; + } + ; + +opt_cycle_clause: + CYCLE columnList SET ColId TO AexprConst DEFAULT AexprConst USING ColId + { + CTECycleClause *n = makeNode(CTECycleClause); + n->cycle_col_list = $2; + n->cycle_mark_column = $4; + n->cycle_mark_value = $6; + n->cycle_mark_default = $8; + n->cycle_path_column = $10; + n->location = @1; + $$ = (Node *) n; + } + | /*EMPTY*/ + { + $$ = NULL; + } + ; + opt_with_clause: with_clause { $$ = $1; } | /*EMPTY*/ { $$ = NULL; } @@ -15079,6 +15123,7 @@ unreserved_keyword: | BACKWARD | BEFORE | BEGIN_P + | BREADTH | BY | CACHE | CALL @@ -15123,6 +15168,7 @@ unreserved_keyword: | DELIMITER | DELIMITERS | DEPENDS + | DEPTH | DETACH | DICTIONARY | DISABLE_P @@ -15590,6 +15636,7 @@ bare_label_keyword: | BIT | BOOLEAN_P | BOTH + | BREADTH | BY | CACHE | CALL @@ -15654,6 +15701,7 @@ bare_label_keyword: | DELIMITER | DELIMITERS | DEPENDS + | DEPTH | DESC | DETACH | DICTIONARY diff --git a/src/backend/parser/parse_agg.c b/src/backend/parser/parse_agg.c index 783f3fe8f2..dd3d97d85f 100644 --- a/src/backend/parser/parse_agg.c +++ b/src/backend/parser/parse_agg.c @@ -545,6 +545,10 @@ check_agglevels_and_constraints(ParseState *pstate, Node *expr) break; + case EXPR_KIND_CYCLE_MARK: + errkind = true; + break; + /* * There is intentionally no default: case here, so that the * compiler will warn if we add a new ParseExprKind without @@ -933,6 +937,9 @@ transformWindowFuncCall(ParseState *pstate, WindowFunc *wfunc, case EXPR_KIND_GENERATED_COLUMN: err = _("window functions are not allowed in column generation expressions"); break; + case EXPR_KIND_CYCLE_MARK: + errkind = true; + break; /* * There is intentionally no default: case here, so that the diff --git a/src/backend/parser/parse_cte.c b/src/backend/parser/parse_cte.c index 1fca7485ca..87dedb4c28 100644 --- a/src/backend/parser/parse_cte.c +++ b/src/backend/parser/parse_cte.c @@ -18,7 +18,10 @@ #include "catalog/pg_type.h" #include "nodes/nodeFuncs.h" #include "parser/analyze.h" +#include "parser/parse_coerce.h" +#include "parser/parse_collate.h" #include "parser/parse_cte.h" +#include "parser/parse_expr.h" #include "utils/builtins.h" #include "utils/lsyscache.h" @@ -334,6 +337,120 @@ analyzeCTE(ParseState *pstate, CommonTableExpr *cte) if (lctyp != NULL || lctypmod != NULL || lccoll != NULL) /* shouldn't happen */ elog(ERROR, "wrong number of output columns in WITH"); } + + if (cte->search_clause || cte->cycle_clause) + { + if (!cte->cterecursive) + ereport(ERROR, + (errcode(ERRCODE_SYNTAX_ERROR), + errmsg("WITH query is not recursive"), + parser_errposition(pstate, cte->location))); + + /* + * SQL requires a WITH list element (CTE) to be "expandable" in order + * to allow a search or cycle clause. That is a stronger requirement + * than just being recursive. As of this writing, PostgreSQL only + * allows expandable CTEs as recursive CTEs anyway. In the future, + * there might be further checks required here. + */ + } + + if (cte->search_clause) + { + ListCell *lc; + List *seen = NIL; + + foreach(lc, cte->search_clause->search_col_list) + { + Value *colname = lfirst(lc); + + if (!list_member(cte->ctecolnames, colname)) + ereport(ERROR, + (errcode(ERRCODE_SYNTAX_ERROR), + errmsg("search column \"%s\" not in WITH query column list", + strVal(colname)), + parser_errposition(pstate, cte->search_clause->location))); + + if (list_member(seen, colname)) + ereport(ERROR, + (errcode(ERRCODE_DUPLICATE_COLUMN), + errmsg("search column \"%s\" specified more than once", + strVal(colname)), + parser_errposition(pstate, cte->search_clause->location))); + seen = lappend(seen, colname); + } + + if (list_member(cte->ctecolnames, makeString(cte->search_clause->search_seq_column))) + ereport(ERROR, + errcode(ERRCODE_SYNTAX_ERROR), + errmsg("search sequence column name \"%s\" already used in WITH query column list", + cte->search_clause->search_seq_column), + parser_errposition(pstate, cte->search_clause->location)); + } + + if (cte->cycle_clause) + { + ListCell *lc; + List *seen = NIL; + int typmod1; + int typmod2; + + foreach(lc, cte->cycle_clause->cycle_col_list) + { + Value *colname = lfirst(lc); + + if (!list_member(cte->ctecolnames, colname)) + ereport(ERROR, + (errcode(ERRCODE_SYNTAX_ERROR), + errmsg("cycle column \"%s\" not in WITH query column list", + strVal(colname)), + parser_errposition(pstate, cte->cycle_clause->location))); + + if (list_member(seen, colname)) + ereport(ERROR, + (errcode(ERRCODE_DUPLICATE_COLUMN), + errmsg("cycle column \"%s\" specified more than once", + strVal(colname)), + parser_errposition(pstate, cte->cycle_clause->location))); + seen = lappend(seen, colname); + } + + if (list_member(cte->ctecolnames, makeString(cte->cycle_clause->cycle_mark_column))) + ereport(ERROR, + errcode(ERRCODE_SYNTAX_ERROR), + errmsg("cycle column name \"%s\" already used in WITH query column list", + cte->cycle_clause->cycle_mark_column), + parser_errposition(pstate, cte->cycle_clause->location)); + + cte->cycle_clause->cycle_mark_value = transformExpr(pstate, cte->cycle_clause->cycle_mark_value, + EXPR_KIND_CYCLE_MARK); + cte->cycle_clause->cycle_mark_default = transformExpr(pstate, cte->cycle_clause->cycle_mark_default, + EXPR_KIND_CYCLE_MARK); + cte->cycle_clause->cycle_mark_type = select_common_type(pstate, + list_make2(cte->cycle_clause->cycle_mark_value, + cte->cycle_clause->cycle_mark_default), + "CYCLE", NULL); + cte->cycle_clause->cycle_mark_value = coerce_to_common_type(pstate, + cte->cycle_clause->cycle_mark_value, + cte->cycle_clause->cycle_mark_type, + "CYCLE/SET/TO"); + cte->cycle_clause->cycle_mark_default = coerce_to_common_type(pstate, + cte->cycle_clause->cycle_mark_default, + cte->cycle_clause->cycle_mark_type, + "CYCLE/SET/DEFAULT"); + + typmod1 = exprTypmod(cte->cycle_clause->cycle_mark_value); + typmod2 = exprTypmod(cte->cycle_clause->cycle_mark_default); + if (typmod1 == typmod2) + cte->cycle_clause->cycle_mark_typmod = typmod1; + else + cte->cycle_clause->cycle_mark_typmod = -1; + + cte->cycle_clause->cycle_mark_collation = select_common_collation(pstate, + list_make2(cte->cycle_clause->cycle_mark_value, + cte->cycle_clause->cycle_mark_default), + true); + } } /* diff --git a/src/backend/parser/parse_expr.c b/src/backend/parser/parse_expr.c index d24420c583..a91ebce7ea 100644 --- a/src/backend/parser/parse_expr.c +++ b/src/backend/parser/parse_expr.c @@ -571,6 +571,7 @@ transformColumnRef(ParseState *pstate, ColumnRef *cref) case EXPR_KIND_CALL_ARGUMENT: case EXPR_KIND_COPY_WHERE: case EXPR_KIND_GENERATED_COLUMN: + case EXPR_KIND_CYCLE_MARK: /* okay */ break; @@ -1897,6 +1898,7 @@ transformSubLink(ParseState *pstate, SubLink *sublink) case EXPR_KIND_RETURNING: case EXPR_KIND_VALUES: case EXPR_KIND_VALUES_SINGLE: + case EXPR_KIND_CYCLE_MARK: /* okay */ break; case EXPR_KIND_CHECK_CONSTRAINT: @@ -3541,6 +3543,8 @@ ParseExprKindName(ParseExprKind exprKind) return "WHERE"; case EXPR_KIND_GENERATED_COLUMN: return "GENERATED AS"; + case EXPR_KIND_CYCLE_MARK: + return "CYCLE"; /* * There is intentionally no default: case here, so that the diff --git a/src/backend/parser/parse_func.c b/src/backend/parser/parse_func.c index 9c3b6ad916..57c376a4ad 100644 --- a/src/backend/parser/parse_func.c +++ b/src/backend/parser/parse_func.c @@ -2519,6 +2519,9 @@ check_srf_call_placement(ParseState *pstate, Node *last_srf, int location) case EXPR_KIND_GENERATED_COLUMN: err = _("set-returning functions are not allowed in column generation expressions"); break; + case EXPR_KIND_CYCLE_MARK: + errkind = true; + break; /* * There is intentionally no default: case here, so that the diff --git a/src/backend/parser/parse_relation.c b/src/backend/parser/parse_relation.c index a56bd86181..a5efd39499 100644 --- a/src/backend/parser/parse_relation.c +++ b/src/backend/parser/parse_relation.c @@ -2235,6 +2235,8 @@ addRangeTableEntryForCTE(ParseState *pstate, int numaliases; int varattno; ListCell *lc; + int n_dontexpand_columns = 0; + ParseNamespaceItem *psi; Assert(pstate != NULL); @@ -2267,9 +2269,9 @@ addRangeTableEntryForCTE(ParseState *pstate, parser_errposition(pstate, rv->location))); } - rte->coltypes = cte->ctecoltypes; - rte->coltypmods = cte->ctecoltypmods; - rte->colcollations = cte->ctecolcollations; + rte->coltypes = list_copy(cte->ctecoltypes); + rte->coltypmods = list_copy(cte->ctecoltypmods); + rte->colcollations = list_copy(cte->ctecolcollations); rte->alias = alias; if (alias) @@ -2294,6 +2296,34 @@ addRangeTableEntryForCTE(ParseState *pstate, rte->eref = eref; + if (cte->search_clause) + { + rte->eref->colnames = lappend(rte->eref->colnames, makeString(cte->search_clause->search_seq_column)); + if (cte->search_clause->search_breadth_first) + rte->coltypes = lappend_oid(rte->coltypes, RECORDOID); + else + rte->coltypes = lappend_oid(rte->coltypes, RECORDARRAYOID); + rte->coltypmods = lappend_int(rte->coltypmods, -1); + rte->colcollations = lappend_oid(rte->colcollations, InvalidOid); + + n_dontexpand_columns += 1; + } + + if (cte->cycle_clause) + { + rte->eref->colnames = lappend(rte->eref->colnames, makeString(cte->cycle_clause->cycle_mark_column)); + rte->coltypes = lappend_oid(rte->coltypes, cte->cycle_clause->cycle_mark_type); + rte->coltypmods = lappend_int(rte->coltypmods, cte->cycle_clause->cycle_mark_typmod); + rte->colcollations = lappend_oid(rte->colcollations, cte->cycle_clause->cycle_mark_collation); + + rte->eref->colnames = lappend(rte->eref->colnames, makeString(cte->cycle_clause->cycle_path_column)); + rte->coltypes = lappend_oid(rte->coltypes, RECORDARRAYOID); + rte->coltypmods = lappend_int(rte->coltypmods, -1); + rte->colcollations = lappend_oid(rte->colcollations, InvalidOid); + + n_dontexpand_columns += 2; + } + /* * Set flags and access permissions. * @@ -2321,9 +2351,19 @@ addRangeTableEntryForCTE(ParseState *pstate, * Build a ParseNamespaceItem, but don't add it to the pstate's namespace * list --- caller must do that if appropriate. */ - return buildNSItemFromLists(rte, list_length(pstate->p_rtable), + psi = buildNSItemFromLists(rte, list_length(pstate->p_rtable), rte->coltypes, rte->coltypmods, rte->colcollations); + + /* + * The columns added by search and cycle clauses are not included in star + * expansion in queries contained in the CTE. + */ + if (rte->ctelevelsup > 0) + for (int i = 0; i < n_dontexpand_columns; i++) + psi->p_nscolumns[list_length(psi->p_rte->eref->colnames) - 1 - i].p_dontexpand = true; + + return psi; } /* @@ -3008,7 +3048,11 @@ expandNSItemVars(ParseNamespaceItem *nsitem, const char *colname = strVal(colnameval); ParseNamespaceColumn *nscol = nsitem->p_nscolumns + colindex; - if (colname[0]) + if (nscol->p_dontexpand) + { + /* skip */ + } + else if (colname[0]) { Var *var; diff --git a/src/backend/parser/parse_target.c b/src/backend/parser/parse_target.c index 566c517837..70120bb537 100644 --- a/src/backend/parser/parse_target.c +++ b/src/backend/parser/parse_target.c @@ -409,10 +409,25 @@ markTargetListOrigin(ParseState *pstate, TargetEntry *tle, { CommonTableExpr *cte = GetCTEForRTE(pstate, rte, netlevelsup); TargetEntry *ste; + List *tl = GetCTETargetList(cte); + int extra_cols = 0; + + /* + * RTE for CTE will already have the search and cycle columns + * added, but the subquery won't, so skip looking those up. + */ + if (cte->search_clause) + extra_cols += 1; + if (cte->cycle_clause) + extra_cols += 2; + if (extra_cols && + attnum > list_length(tl) && + attnum <= list_length(tl) + extra_cols) + break; - ste = get_tle_by_resno(GetCTETargetList(cte), attnum); + ste = get_tle_by_resno(tl, attnum); if (ste == NULL || ste->resjunk) - elog(ERROR, "subquery %s does not have attribute %d", + elog(ERROR, "CTE %s does not have attribute %d", rte->eref->aliasname, attnum); tle->resorigtbl = ste->resorigtbl; tle->resorigcol = ste->resorigcol; @@ -1606,7 +1621,7 @@ expandRecordVariable(ParseState *pstate, Var *var, int levelsup) ste = get_tle_by_resno(GetCTETargetList(cte), attnum); if (ste == NULL || ste->resjunk) - elog(ERROR, "subquery %s does not have attribute %d", + elog(ERROR, "CTE %s does not have attribute %d", rte->eref->aliasname, attnum); expr = (Node *) ste->expr; if (IsA(expr, Var)) diff --git a/src/backend/rewrite/Makefile b/src/backend/rewrite/Makefile index b435b3e985..4680752e6a 100644 --- a/src/backend/rewrite/Makefile +++ b/src/backend/rewrite/Makefile @@ -17,6 +17,7 @@ OBJS = \ rewriteHandler.o \ rewriteManip.o \ rewriteRemove.o \ + rewriteSearchCycle.o \ rewriteSupport.o \ rowsecurity.o diff --git a/src/backend/rewrite/rewriteHandler.c b/src/backend/rewrite/rewriteHandler.c index fe777c3103..74b0fa7cdf 100644 --- a/src/backend/rewrite/rewriteHandler.c +++ b/src/backend/rewrite/rewriteHandler.c @@ -37,6 +37,7 @@ #include "rewrite/rewriteDefine.h" #include "rewrite/rewriteHandler.h" #include "rewrite/rewriteManip.h" +#include "rewrite/rewriteSearchCycle.h" #include "rewrite/rowsecurity.h" #include "utils/builtins.h" #include "utils/lsyscache.h" @@ -1864,6 +1865,23 @@ fireRIRrules(Query *parsetree, List *activeRIRs) int rt_index; ListCell *lc; + /* + * Expand SEARCH and CYCLE clauses in CTEs. + * + * This is just a convenient place to do this, since we are already + * looking at each Query. + */ + foreach(lc, parsetree->cteList) + { + CommonTableExpr *cte = lfirst_node(CommonTableExpr, lc); + + if (cte->search_clause || cte->cycle_clause) + { + cte = rewriteSearchAndCycle(cte); + lfirst(lc) = cte; + } + } + /* * don't try to convert this into a foreach loop, because rtable list can * get changed each time through... diff --git a/src/backend/rewrite/rewriteSearchCycle.c b/src/backend/rewrite/rewriteSearchCycle.c new file mode 100644 index 0000000000..8053fea907 --- /dev/null +++ b/src/backend/rewrite/rewriteSearchCycle.c @@ -0,0 +1,709 @@ +/*------------------------------------------------------------------------- + * + * rewriteSearchCycle.c + * Support for rewriting SEARCH and CYCLE clauses. + * + * Portions Copyright (c) 1996-2020, PostgreSQL Global Development Group + * Portions Copyright (c) 1994, Regents of the University of California + * + * IDENTIFICATION + * src/backend/rewrite/rewriteSearchCycle.c + * + *------------------------------------------------------------------------- + */ +#include "postgres.h" + +#include "catalog/pg_operator_d.h" +#include "catalog/pg_type_d.h" +#include "nodes/makefuncs.h" +#include "nodes/pg_list.h" +#include "parser/analyze.h" +#include "parser/parsetree.h" +#include "rewrite/rewriteManip.h" +#include "rewrite/rewriteSearchCycle.h" +#include "utils/builtins.h" +#include "utils/fmgroids.h" +#include "utils/lsyscache.h" +#include "utils/typcache.h" + + +/*---------- + * Rewrite a CTE with SEARCH or CYCLE clause + * + * Consider a CTE like + * + * WITH RECURSIVE ctename (col1, col2, col3) AS ( + * query1 + * UNION [ALL] + * SELECT trosl FROM ctename + * ) + * + * With a search clause + * + * SEARCH BREADTH FIRST BY col1, col2 SET sqc + * + * the CTE is rewritten to + * + * WITH RECURSIVE ctename (col1, col2, col3, sqc) AS ( + * SELECT col1, col2, col3, -- original WITH column list + * ROW(0, col1, col2) -- initial row of search columns + * FROM (query1) "*TLOCRN*" (col1, col2, col3) + * UNION [ALL] + * SELECT col1, col2, col3, -- same as above + * ROW(sqc.level + 1, col1, col2) -- count levels + * FROM (SELECT trosl, ctename.sqc FROM ctename) "*TROCRN*" (col1, col2, col3, sqc) + * ) + * + * (This isn't quite legal SQL: sqc.level is meant to refer to the first + * column of sqc, which has a row type, but the field names are not defined + * here. Representing this properly in SQL would be more complicated (and the + * SQL standard actually does it in that more complicated way), but the + * internal representation allows us to construct it this way.) + * + * With a search caluse + * + * SEARCH DEPTH FIRST BY col1, col2 SET sqc + * + * the CTE is rewritten to + * + * WITH RECURSIVE ctename (col1, col2, col3, sqc) AS ( + * SELECT col1, col2, col3, -- original WITH column list + * ARRAY[ROW(col1, col2)] -- initial row of search columns + * FROM (query1) "*TLOCRN*" (col1, col2, col3) + * UNION [ALL] + * SELECT col1, col2, col3, -- same as above + * sqc || ARRAY[ROW(col1, col2)] -- record rows seen + * FROM (SELECT trosl, ctename.sqc FROM ctename) "*TROCRN*" (col1, col2, col3, sqc) + * ) + * + * With a cycle clause + * + * CYCLE col1, col2 SET cmc TO 'Y' DEFAULT 'N' USING cpa + * + * (cmc = cycle mark column, cpa = cycle path) the CTE is rewritten to + * + * WITH RECURSIVE ctename (col1, col2, col3, cmc, cpa) AS ( + * SELECT col1, col2, col3, -- original WITH column list + * 'N', -- cycle mark default + * ARRAY[ROW(col1, col2)] -- initial row of cycle columns + * FROM (query1) "*TLOCRN*" (col1, col2, col3) + * UNION [ALL] + * SELECT col1, col2, col3, -- same as above + * CASE WHEN ROW(col1, col2) = ANY (ARRAY[cpa]) THEN 'Y' ELSE 'N' END, -- compute cycle mark column + * cpa || ARRAY[ROW(col1, col2)] -- record rows seen + * FROM (SELECT trosl, ctename.cmc, ctename.cpa FROM ctename) "*TROCRN*" (col1, col2, col3, cmc, cpa) + * WHERE cmc <> 'Y' + * ) + * + * The expression to compute the cycle mark column in the right-hand query is + * written as + * + * CASE WHEN ROW(col1, col2) IN (SELECT p.* FROM TABLE(cpa) p) THEN cmv ELSE cmd END + * + * in the SQL standard, but in PostgreSQL we can use the scalar-array operator + * expression shown above. + * + * Also, in some of the cases where operators are shown above we actually + * directly produce the underlying function call. + * + * If both a search clause and a cycle clause is specified, then the search + * clause column is added before the cycle clause columns. + */ + +/* + * Make a RowExpr from the specified column names, which have to be among the + * output columns of the CTE. + * + * XXX We already looked up the columns in parse_cte.c. Maybe we should + * record the positions there instead of looking them up again here. + */ +static RowExpr * +make_path_rowexpr(const CommonTableExpr *cte, const List *col_list) +{ + RowExpr *rowexpr; + ListCell *lc; + + rowexpr = makeNode(RowExpr); + rowexpr->row_typeid = RECORDOID; + rowexpr->row_format = COERCE_IMPLICIT_CAST; + rowexpr->location = -1; + + foreach(lc, col_list) + { + char *colname = strVal(lfirst(lc)); + + for (int i = 0; i < list_length(cte->ctecolnames); i++) + { + char *colname2 = strVal(list_nth(cte->ctecolnames, i)); + + if (strcmp(colname, colname2) == 0) + { + Var *var; + + var = makeVar(1, i + 1, + list_nth_oid(cte->ctecoltypes, i), + list_nth_int(cte->ctecoltypmods, i), + list_nth_oid(cte->ctecolcollations, i), + 0); + rowexpr->args = lappend(rowexpr->args, var); + rowexpr->colnames = lappend(rowexpr->colnames, makeString(colname)); + break; + } + } + } + + return rowexpr; +} + +/* + * Wrap a RowExpr in an ArrayExpr, for the initial search depth first or cycle + * row. + */ +static Expr * +make_path_initial_array(RowExpr *rowexpr) +{ + ArrayExpr *arr; + + arr = makeNode(ArrayExpr); + arr->array_typeid = RECORDARRAYOID; + arr->element_typeid = RECORDOID; + arr->location = -1; + arr->elements = list_make1(rowexpr); + + return (Expr *) arr; +} + +/* + * Make an array catenation expression like + * + * cpa || ARRAY[ROW(cols)] + * + * where the varattno of cpa is provided as path_varattno. + */ +static Expr * +make_path_cat_expr(RowExpr *rowexpr, AttrNumber path_varattno) +{ + ArrayExpr *arr; + FuncExpr *fexpr; + + arr = makeNode(ArrayExpr); + arr->array_typeid = RECORDARRAYOID; + arr->element_typeid = RECORDOID; + arr->location = -1; + arr->elements = list_make1(rowexpr); + + fexpr = makeFuncExpr(F_ARRAY_CAT, RECORDARRAYOID, + list_make2(makeVar(1, path_varattno, RECORDARRAYOID, -1, 0, 0), + arr), + InvalidOid, InvalidOid, COERCE_EXPLICIT_CALL); + + return (Expr *) fexpr; +} + +/* + * The real work happens here. + */ +CommonTableExpr * +rewriteSearchAndCycle(CommonTableExpr *cte) +{ + Query *ctequery; + SetOperationStmt *sos; + int rti1, + rti2; + RangeTblEntry *rte1, + *rte2, + *newrte; + Query *newq1, + *newq2; + Query *newsubquery; + RangeTblRef *rtr; + Oid search_seq_type = InvalidOid; + AttrNumber sqc_attno = InvalidAttrNumber; + AttrNumber cmc_attno = InvalidAttrNumber; + AttrNumber cpa_attno = InvalidAttrNumber; + TargetEntry *tle; + RowExpr *cycle_col_rowexpr = NULL; + RowExpr *search_col_rowexpr = NULL; + List *ewcl; + int cte_rtindex = -1; + + Assert(cte->search_clause || cte->cycle_clause); + + cte = copyObject(cte); + + ctequery = castNode(Query, cte->ctequery); + + /* + * The top level of the CTE's query should be a UNION. Find the two + * subqueries. + */ + Assert(ctequery->setOperations); + sos = castNode(SetOperationStmt, ctequery->setOperations); + Assert(sos->op == SETOP_UNION); + + /* + * XXX The SEARCH and CYCLE clauses won't currently work with UNION + * DISTINCT, because the record and _record types are not hashable. This + * would result in a perhaps slightly confusing error message later, so + * we'll give a more precise message here. If that restriction is ever + * lifted, this can be removed. + */ + if (!sos->all) + { + if (cte->search_clause) + ereport(ERROR, + errcode(ERRCODE_FEATURE_NOT_SUPPORTED), + errmsg("SEARCH clause not supported with UNION DISTINCT")); + if (cte->cycle_clause) + ereport(ERROR, + errcode(ERRCODE_FEATURE_NOT_SUPPORTED), + errmsg("CYCLE clause not supported with UNION DISTINCT")); + } + + rti1 = castNode(RangeTblRef, sos->larg)->rtindex; + rti2 = castNode(RangeTblRef, sos->rarg)->rtindex; + + rte1 = rt_fetch(rti1, ctequery->rtable); + rte2 = rt_fetch(rti2, ctequery->rtable); + + Assert(rte1->rtekind == RTE_SUBQUERY); + Assert(rte2->rtekind == RTE_SUBQUERY); + + /* + * We'll need this a few times later. + */ + if (cte->search_clause) + { + if (cte->search_clause->search_breadth_first) + search_seq_type = RECORDOID; + else + search_seq_type = RECORDARRAYOID; + } + + /* + * Attribute numbers of the added columns in the CTE's column list + */ + if (cte->search_clause) + sqc_attno = list_length(cte->ctecolnames) + 1; + if (cte->cycle_clause) + { + cmc_attno = list_length(cte->ctecolnames) + 1; + cpa_attno = list_length(cte->ctecolnames) + 2; + if (cte->search_clause) + { + cmc_attno++; + cpa_attno++; + } + } + + /* + * Make new left subquery + */ + newq1 = makeNode(Query); + newq1->commandType = CMD_SELECT; + newq1->canSetTag = true; + + newrte = makeNode(RangeTblEntry); + newrte->rtekind = RTE_SUBQUERY; + newrte->alias = makeAlias("*TLOCRN*", cte->ctecolnames); + newrte->eref = newrte->alias; + newsubquery = copyObject(rte1->subquery); + IncrementVarSublevelsUp((Node *) newsubquery, 1, 1); + newrte->subquery = newsubquery; + newrte->inFromCl = true; + newq1->rtable = list_make1(newrte); + + rtr = makeNode(RangeTblRef); + rtr->rtindex = 1; + newq1->jointree = makeFromExpr(list_make1(rtr), NULL); + + /* + * Make target list + */ + for (int i = 0; i < list_length(cte->ctecolnames); i++) + { + Var *var; + + var = makeVar(1, i + 1, + list_nth_oid(cte->ctecoltypes, i), + list_nth_int(cte->ctecoltypmods, i), + list_nth_oid(cte->ctecolcollations, i), + 0); + tle = makeTargetEntry((Expr *) var, i + 1, strVal(list_nth(cte->ctecolnames, i)), false); + tle->resorigtbl = castNode(TargetEntry, list_nth(rte1->subquery->targetList, i))->resorigtbl; + tle->resorigcol = castNode(TargetEntry, list_nth(rte1->subquery->targetList, i))->resorigcol; + newq1->targetList = lappend(newq1->targetList, tle); + } + + if (cte->search_clause) + { + Expr *texpr; + + search_col_rowexpr = make_path_rowexpr(cte, cte->search_clause->search_col_list); + if (cte->search_clause->search_breadth_first) + { + search_col_rowexpr->args = lcons(makeConst(INT8OID, -1, InvalidOid, sizeof(int64), + Int64GetDatum(0), false, FLOAT8PASSBYVAL), + search_col_rowexpr->args); + search_col_rowexpr->colnames = lcons(makeString("*LEVEL*"), search_col_rowexpr->colnames); + texpr = (Expr *) search_col_rowexpr; + } + else + texpr = make_path_initial_array(search_col_rowexpr); + tle = makeTargetEntry(texpr, + list_length(newq1->targetList) + 1, + cte->search_clause->search_seq_column, + false); + newq1->targetList = lappend(newq1->targetList, tle); + } + if (cte->cycle_clause) + { + tle = makeTargetEntry((Expr *) cte->cycle_clause->cycle_mark_default, + list_length(newq1->targetList) + 1, + cte->cycle_clause->cycle_mark_column, + false); + newq1->targetList = lappend(newq1->targetList, tle); + cycle_col_rowexpr = make_path_rowexpr(cte, cte->cycle_clause->cycle_col_list); + tle = makeTargetEntry(make_path_initial_array(cycle_col_rowexpr), + list_length(newq1->targetList) + 1, + cte->cycle_clause->cycle_path_column, + false); + newq1->targetList = lappend(newq1->targetList, tle); + } + + rte1->subquery = newq1; + + if (cte->search_clause) + { + rte1->eref->colnames = lappend(rte1->eref->colnames, makeString(cte->search_clause->search_seq_column)); + } + if (cte->cycle_clause) + { + rte1->eref->colnames = lappend(rte1->eref->colnames, makeString(cte->cycle_clause->cycle_mark_column)); + rte1->eref->colnames = lappend(rte1->eref->colnames, makeString(cte->cycle_clause->cycle_path_column)); + } + + /* + * Make new right subquery + */ + newq2 = makeNode(Query); + newq2->commandType = CMD_SELECT; + newq2->canSetTag = true; + + newrte = makeNode(RangeTblEntry); + newrte->rtekind = RTE_SUBQUERY; + ewcl = copyObject(cte->ctecolnames); + if (cte->search_clause) + { + ewcl = lappend(ewcl, makeString(cte->search_clause->search_seq_column)); + } + if (cte->cycle_clause) + { + ewcl = lappend(ewcl, makeString(cte->cycle_clause->cycle_mark_column)); + ewcl = lappend(ewcl, makeString(cte->cycle_clause->cycle_path_column)); + } + newrte->alias = makeAlias("*TROCRN*", ewcl); + newrte->eref = newrte->alias; + + /* + * Find the reference to our CTE in the range table + */ + for (int rti = 1; rti <= list_length(rte2->subquery->rtable); rti++) + { + RangeTblEntry *e = rt_fetch(rti, rte2->subquery->rtable); + + if (e->rtekind == RTE_CTE && strcmp(cte->ctename, e->ctename) == 0) + { + cte_rtindex = rti; + break; + } + } + Assert(cte_rtindex > 0); + + newsubquery = copyObject(rte2->subquery); + IncrementVarSublevelsUp((Node *) newsubquery, 1, 1); + + /* + * Add extra columns to target list of subquery of right subquery + */ + if (cte->search_clause) + { + Var *var; + + /* ctename.sqc */ + var = makeVar(cte_rtindex, sqc_attno, + search_seq_type, -1, InvalidOid, 0); + tle = makeTargetEntry((Expr *) var, + list_length(newsubquery->targetList) + 1, + cte->search_clause->search_seq_column, + false); + newsubquery->targetList = lappend(newsubquery->targetList, tle); + } + if (cte->cycle_clause) + { + Var *var; + + /* ctename.cmc */ + var = makeVar(cte_rtindex, cmc_attno, + cte->cycle_clause->cycle_mark_type, + cte->cycle_clause->cycle_mark_typmod, + cte->cycle_clause->cycle_mark_collation, 0); + tle = makeTargetEntry((Expr *) var, + list_length(newsubquery->targetList) + 1, + cte->cycle_clause->cycle_mark_column, + false); + newsubquery->targetList = lappend(newsubquery->targetList, tle); + + /* ctename.cpa */ + var = makeVar(cte_rtindex, cpa_attno, + RECORDARRAYOID, -1, InvalidOid, 0); + tle = makeTargetEntry((Expr *) var, + list_length(newsubquery->targetList) + 1, + cte->cycle_clause->cycle_path_column, + false); + newsubquery->targetList = lappend(newsubquery->targetList, tle); + } + + newrte->subquery = newsubquery; + newrte->inFromCl = true; + newq2->rtable = list_make1(newrte); + + rtr = makeNode(RangeTblRef); + rtr->rtindex = 1; + + if (cte->cycle_clause) + { + TypeCacheEntry *typentry; + Oid op; + OpExpr *opexpr; + + /* + * Add cmc <> cmv condition + */ + + typentry = lookup_type_cache(cte->cycle_clause->cycle_mark_type, TYPECACHE_EQ_OPR); + if (!typentry->eq_opr) + ereport(ERROR, + errcode(ERRCODE_UNDEFINED_FUNCTION), + errmsg("could not identify an equality operator for type %s", + format_type_be(cte->cycle_clause->cycle_mark_type))); + op = get_negator(typentry->eq_opr); + if (!op) + ereport(ERROR, + errcode(ERRCODE_UNDEFINED_FUNCTION), + errmsg("could not identify an inequality operator for type %s", + format_type_be(cte->cycle_clause->cycle_mark_type))); + + opexpr = makeNode(OpExpr); + opexpr->location = -1; + opexpr->opno = op; + opexpr->opresulttype = BOOLOID; + opexpr->inputcollid = cte->cycle_clause->cycle_mark_collation; + opexpr->args = list_make2(makeVar(1, cmc_attno, + cte->cycle_clause->cycle_mark_type, + cte->cycle_clause->cycle_mark_typmod, + cte->cycle_clause->cycle_mark_collation, 0), + cte->cycle_clause->cycle_mark_value); + + newq2->jointree = makeFromExpr(list_make1(rtr), (Node *) opexpr); + } + else + newq2->jointree = makeFromExpr(list_make1(rtr), NULL); + + /* + * Make target list + */ + for (int i = 0; i < list_length(cte->ctecolnames); i++) + { + Var *var; + + var = makeVar(1, i + 1, + list_nth_oid(cte->ctecoltypes, i), + list_nth_int(cte->ctecoltypmods, i), + list_nth_oid(cte->ctecolcollations, i), + 0); + tle = makeTargetEntry((Expr *) var, i + 1, strVal(list_nth(cte->ctecolnames, i)), false); + tle->resorigtbl = castNode(TargetEntry, list_nth(rte2->subquery->targetList, i))->resorigtbl; + tle->resorigcol = castNode(TargetEntry, list_nth(rte2->subquery->targetList, i))->resorigcol; + newq2->targetList = lappend(newq2->targetList, tle); + } + + if (cte->search_clause) + { + Expr *texpr; + + if (cte->search_clause->search_breadth_first) + { + FieldSelect *fs; + FuncExpr *fexpr; + + /* + * ROW(sqc.level + 1, cols) + */ + + search_col_rowexpr = copyObject(search_col_rowexpr); + + fs = makeNode(FieldSelect); + fs->arg = (Expr *) makeVar(1, sqc_attno, RECORDOID, -1, 0, 0); + fs->fieldnum = 1; + fs->resulttype = INT8OID; + fs->resulttypmod = -1; + + fexpr = makeFuncExpr(F_INT8INC, INT8OID, list_make1(fs), InvalidOid, InvalidOid, COERCE_EXPLICIT_CALL); + + lfirst(list_head(search_col_rowexpr->args)) = fexpr; + + texpr = (Expr *) search_col_rowexpr; + } + else + { + /* + * sqc || ARRAY[ROW(cols)] + */ + texpr = make_path_cat_expr(search_col_rowexpr, sqc_attno); + } + tle = makeTargetEntry(texpr, + list_length(newq2->targetList) + 1, + cte->search_clause->search_seq_column, + false); + newq2->targetList = lappend(newq2->targetList, tle); + } + + if (cte->cycle_clause) + { + ScalarArrayOpExpr *saoe; + CaseExpr *caseexpr; + CaseWhen *casewhen; + + /* + * CASE WHEN ROW(cols) = ANY (ARRAY[cpa]) THEN cmv ELSE cmd END + */ + + saoe = makeNode(ScalarArrayOpExpr); + saoe->location = -1; + saoe->opno = RECORD_EQ_OP; + saoe->useOr = true; + saoe->args = list_make2(cycle_col_rowexpr, + makeVar(1, cpa_attno, RECORDARRAYOID, -1, 0, 0)); + + caseexpr = makeNode(CaseExpr); + caseexpr->location = -1; + caseexpr->casetype = cte->cycle_clause->cycle_mark_type; + caseexpr->casecollid = cte->cycle_clause->cycle_mark_collation; + casewhen = makeNode(CaseWhen); + casewhen->location = -1; + casewhen->expr = (Expr *) saoe; + casewhen->result = (Expr *) cte->cycle_clause->cycle_mark_value; + caseexpr->args = list_make1(casewhen); + caseexpr->defresult = (Expr *) cte->cycle_clause->cycle_mark_default; + + tle = makeTargetEntry((Expr *) caseexpr, + list_length(newq2->targetList) + 1, + cte->cycle_clause->cycle_mark_column, + false); + newq2->targetList = lappend(newq2->targetList, tle); + + /* + * cpa || ARRAY[ROW(cols)] + */ + tle = makeTargetEntry(make_path_cat_expr(cycle_col_rowexpr, cpa_attno), + list_length(newq2->targetList) + 1, + cte->cycle_clause->cycle_path_column, + false); + newq2->targetList = lappend(newq2->targetList, tle); + } + + rte2->subquery = newq2; + + if (cte->search_clause) + { + rte2->eref->colnames = lappend(rte2->eref->colnames, makeString(cte->search_clause->search_seq_column)); + } + if (cte->cycle_clause) + { + rte2->eref->colnames = lappend(rte2->eref->colnames, makeString(cte->cycle_clause->cycle_mark_column)); + rte2->eref->colnames = lappend(rte2->eref->colnames, makeString(cte->cycle_clause->cycle_path_column)); + } + + /* + * Add the additional columns to the SetOperationStmt + */ + if (cte->search_clause) + { + sos->colTypes = lappend_oid(sos->colTypes, search_seq_type); + sos->colTypmods = lappend_int(sos->colTypmods, -1); + sos->colCollations = lappend_oid(sos->colCollations, InvalidOid); + if (!sos->all) + sos->groupClauses = lappend(sos->groupClauses, + makeSortGroupClauseForSetOp(search_seq_type)); + } + if (cte->cycle_clause) + { + sos->colTypes = lappend_oid(sos->colTypes, cte->cycle_clause->cycle_mark_type); + sos->colTypmods = lappend_int(sos->colTypmods, cte->cycle_clause->cycle_mark_typmod); + sos->colCollations = lappend_oid(sos->colCollations, cte->cycle_clause->cycle_mark_collation); + if (!sos->all) + sos->groupClauses = lappend(sos->groupClauses, + makeSortGroupClauseForSetOp(cte->cycle_clause->cycle_mark_type)); + + sos->colTypes = lappend_oid(sos->colTypes, RECORDARRAYOID); + sos->colTypmods = lappend_int(sos->colTypmods, -1); + sos->colCollations = lappend_oid(sos->colCollations, InvalidOid); + if (!sos->all) + sos->groupClauses = lappend(sos->groupClauses, + makeSortGroupClauseForSetOp(RECORDARRAYOID)); + } + + /* + * Add the additional columns to the CTE query's target list + */ + if (cte->search_clause) + { + ctequery->targetList = lappend(ctequery->targetList, + makeTargetEntry((Expr *) makeVar(1, sqc_attno, + search_seq_type, -1, InvalidOid, 0), + list_length(ctequery->targetList) + 1, + cte->search_clause->search_seq_column, + false)); + } + if (cte->cycle_clause) + { + ctequery->targetList = lappend(ctequery->targetList, + makeTargetEntry((Expr *) makeVar(1, cmc_attno, + cte->cycle_clause->cycle_mark_type, + cte->cycle_clause->cycle_mark_typmod, + cte->cycle_clause->cycle_mark_collation, 0), + list_length(ctequery->targetList) + 1, + cte->cycle_clause->cycle_mark_column, + false)); + ctequery->targetList = lappend(ctequery->targetList, + makeTargetEntry((Expr *) makeVar(1, cpa_attno, + RECORDARRAYOID, -1, InvalidOid, 0), + list_length(ctequery->targetList) + 1, + cte->cycle_clause->cycle_path_column, + false)); + } + + /* + * Add the additional columns to the CTE's output columns + */ + cte->ctecolnames = ewcl; + if (cte->search_clause) + { + cte->ctecoltypes = lappend_oid(cte->ctecoltypes, search_seq_type); + cte->ctecoltypmods = lappend_int(cte->ctecoltypmods, -1); + cte->ctecolcollations = lappend_oid(cte->ctecolcollations, InvalidOid); + } + if (cte->cycle_clause) + { + cte->ctecoltypes = lappend_oid(cte->ctecoltypes, cte->cycle_clause->cycle_mark_type); + cte->ctecoltypmods = lappend_int(cte->ctecoltypmods, cte->cycle_clause->cycle_mark_typmod); + cte->ctecolcollations = lappend_oid(cte->ctecolcollations, cte->cycle_clause->cycle_mark_collation); + + cte->ctecoltypes = lappend_oid(cte->ctecoltypes, RECORDARRAYOID); + cte->ctecoltypmods = lappend_int(cte->ctecoltypmods, -1); + cte->ctecolcollations = lappend_oid(cte->ctecolcollations, InvalidOid); + } + + return cte; +} diff --git a/src/backend/utils/adt/ruleutils.c b/src/backend/utils/adt/ruleutils.c index 62023c20b2..ded405f435 100644 --- a/src/backend/utils/adt/ruleutils.c +++ b/src/backend/utils/adt/ruleutils.c @@ -5172,6 +5172,53 @@ get_with_clause(Query *query, deparse_context *context) if (PRETTY_INDENT(context)) appendContextKeyword(context, "", 0, 0, 0); appendStringInfoChar(buf, ')'); + + if (cte->search_clause) + { + bool first = true; + ListCell *lc; + + appendStringInfo(buf, " SEARCH %s FIRST BY ", + cte->search_clause->search_breadth_first ? "BREADTH" : "DEPTH"); + + foreach(lc, cte->search_clause->search_col_list) + { + if (first) + first = false; + else + appendStringInfoString(buf, ", "); + appendStringInfoString(buf, + quote_identifier(strVal(lfirst(lc)))); + } + + appendStringInfo(buf, " SET %s", quote_identifier(cte->search_clause->search_seq_column)); + } + + if (cte->cycle_clause) + { + bool first = true; + ListCell *lc; + + appendStringInfoString(buf, " CYCLE "); + + foreach(lc, cte->cycle_clause->cycle_col_list) + { + if (first) + first = false; + else + appendStringInfoString(buf, ", "); + appendStringInfoString(buf, + quote_identifier(strVal(lfirst(lc)))); + } + + 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); + appendStringInfo(buf, " USING %s", quote_identifier(cte->cycle_clause->cycle_path_column)); + } + sep = ", "; } diff --git a/src/include/nodes/nodes.h b/src/include/nodes/nodes.h index 7ddd8c011b..b375c113e1 100644 --- a/src/include/nodes/nodes.h +++ b/src/include/nodes/nodes.h @@ -471,6 +471,8 @@ typedef enum NodeTag T_WithClause, T_InferClause, T_OnConflictClause, + T_CTESearchClause, + T_CTECycleClause, T_CommonTableExpr, T_RoleSpec, T_TriggerTransition, diff --git a/src/include/nodes/parsenodes.h b/src/include/nodes/parsenodes.h index 60c2f45466..1b54e6bd51 100644 --- a/src/include/nodes/parsenodes.h +++ b/src/include/nodes/parsenodes.h @@ -1435,9 +1435,8 @@ typedef struct OnConflictClause /* * CommonTableExpr - * representation of WITH list element - * - * We don't currently support the SEARCH or CYCLE clause. */ + typedef enum CTEMaterialize { CTEMaterializeDefault, /* no option specified */ @@ -1445,6 +1444,29 @@ typedef enum CTEMaterialize CTEMaterializeNever /* NOT MATERIALIZED */ } CTEMaterialize; +typedef struct CTESearchClause +{ + NodeTag type; + List *search_col_list; + bool search_breadth_first; + char *search_seq_column; + int location; +} CTESearchClause; + +typedef struct CTECycleClause +{ + NodeTag type; + List *cycle_col_list; + char *cycle_mark_column; + Node *cycle_mark_value; + Node *cycle_mark_default; + Oid cycle_mark_type; /* type of _value and _default */ + int cycle_mark_typmod; + Oid cycle_mark_collation; + char *cycle_path_column; + int location; +} CTECycleClause; + typedef struct CommonTableExpr { NodeTag type; @@ -1462,6 +1484,8 @@ typedef struct CommonTableExpr List *ctecoltypes; /* OID list of output column type OIDs */ List *ctecoltypmods; /* integer list of output column typmods */ List *ctecolcollations; /* OID list of column collation OIDs */ + CTESearchClause *search_clause; + CTECycleClause *cycle_clause; } CommonTableExpr; /* Convenience macro to get the output tlist of a CTE's query */ diff --git a/src/include/parser/analyze.h b/src/include/parser/analyze.h index 9d09a02141..52df482ca8 100644 --- a/src/include/parser/analyze.h +++ b/src/include/parser/analyze.h @@ -46,6 +46,8 @@ extern void applyLockingClause(Query *qry, Index rtindex, extern List *BuildOnConflictExcludedTargetlist(Relation targetrel, Index exclRelIndex); +extern SortGroupClause *makeSortGroupClauseForSetOp(Oid rescoltype); + extern void fill_extraUpdatedCols(RangeTblEntry *target_rte, TupleDesc tupdesc); #endif /* ANALYZE_H */ diff --git a/src/include/parser/kwlist.h b/src/include/parser/kwlist.h index 71dcdf2889..9ceab31a2a 100644 --- a/src/include/parser/kwlist.h +++ b/src/include/parser/kwlist.h @@ -60,6 +60,7 @@ PG_KEYWORD("binary", BINARY, TYPE_FUNC_NAME_KEYWORD, BARE_LABEL) PG_KEYWORD("bit", BIT, COL_NAME_KEYWORD, BARE_LABEL) PG_KEYWORD("boolean", BOOLEAN_P, COL_NAME_KEYWORD, BARE_LABEL) PG_KEYWORD("both", BOTH, RESERVED_KEYWORD, BARE_LABEL) +PG_KEYWORD("breadth", BREADTH, UNRESERVED_KEYWORD, BARE_LABEL) PG_KEYWORD("by", BY, UNRESERVED_KEYWORD, BARE_LABEL) PG_KEYWORD("cache", CACHE, UNRESERVED_KEYWORD, BARE_LABEL) PG_KEYWORD("call", CALL, UNRESERVED_KEYWORD, BARE_LABEL) @@ -128,6 +129,7 @@ PG_KEYWORD("delete", DELETE_P, UNRESERVED_KEYWORD, BARE_LABEL) PG_KEYWORD("delimiter", DELIMITER, UNRESERVED_KEYWORD, BARE_LABEL) PG_KEYWORD("delimiters", DELIMITERS, UNRESERVED_KEYWORD, BARE_LABEL) PG_KEYWORD("depends", DEPENDS, UNRESERVED_KEYWORD, BARE_LABEL) +PG_KEYWORD("depth", DEPTH, UNRESERVED_KEYWORD, BARE_LABEL) PG_KEYWORD("desc", DESC, RESERVED_KEYWORD, BARE_LABEL) PG_KEYWORD("detach", DETACH, UNRESERVED_KEYWORD, BARE_LABEL) PG_KEYWORD("dictionary", DICTIONARY, UNRESERVED_KEYWORD, BARE_LABEL) diff --git a/src/include/parser/parse_node.h b/src/include/parser/parse_node.h index d25819aa28..95e8ec85f2 100644 --- a/src/include/parser/parse_node.h +++ b/src/include/parser/parse_node.h @@ -78,6 +78,7 @@ typedef enum ParseExprKind EXPR_KIND_CALL_ARGUMENT, /* procedure argument in CALL */ EXPR_KIND_COPY_WHERE, /* WHERE condition in COPY FROM */ EXPR_KIND_GENERATED_COLUMN, /* generation expression for a column */ + EXPR_KIND_CYCLE_MARK, /* cycle mark value */ } ParseExprKind; @@ -294,6 +295,7 @@ struct ParseNamespaceColumn Oid p_varcollid; /* OID of collation, or InvalidOid */ Index p_varnosyn; /* rangetable index of syntactic referent */ AttrNumber p_varattnosyn; /* attribute number of syntactic referent */ + bool p_dontexpand; /* not included in star expansion */ }; /* Support for parser_errposition_callback function */ diff --git a/src/include/rewrite/rewriteSearchCycle.h b/src/include/rewrite/rewriteSearchCycle.h new file mode 100644 index 0000000000..257fb7cdab --- /dev/null +++ b/src/include/rewrite/rewriteSearchCycle.h @@ -0,0 +1,21 @@ +/*------------------------------------------------------------------------- + * + * rewriteSearchCycle.h + * Support for rewriting SEARCH and CYCLE clauses. + * + * + * Portions Copyright (c) 1996-2020, PostgreSQL Global Development Group + * Portions Copyright (c) 1994, Regents of the University of California + * + * src/include/rewrite/rewriteSearchCycle.h + * + *------------------------------------------------------------------------- + */ +#ifndef REWRITESEARCHCYCLE_H +#define REWRITESEARCHCYCLE_H + +#include "nodes/parsenodes.h" + +extern CommonTableExpr *rewriteSearchAndCycle(CommonTableExpr *cte); + +#endif /* REWRITESEARCHCYCLE_H */ diff --git a/src/test/regress/expected/with.out b/src/test/regress/expected/with.out index 67eaeb4f3e..ac9cb60a83 100644 --- a/src/test/regress/expected/with.out +++ b/src/test/regress/expected/with.out @@ -568,6 +568,148 @@ SELECT t1.id, t2.path, t2 FROM t AS t1 JOIN t AS t2 ON 16 | {3,7,11,16} | (16,"{3,7,11,16}") (16 rows) +-- SEARCH clause +create temp table graph0( f int, t int, label text ); +insert into graph0 values + (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'); +with recursive search_graph(f, t, label) as ( + select * from graph0 g + union all + select g.* + from graph0 g, search_graph sg + where g.f = sg.t +) search depth first by f, t set seq +select * from search_graph order by seq; + f | t | label | seq +---+---+------------+------------------- + 1 | 2 | arc 1 -> 2 | {"(1,2)"} + 2 | 3 | arc 2 -> 3 | {"(1,2)","(2,3)"} + 1 | 3 | arc 1 -> 3 | {"(1,3)"} + 1 | 4 | arc 1 -> 4 | {"(1,4)"} + 4 | 5 | arc 4 -> 5 | {"(1,4)","(4,5)"} + 2 | 3 | arc 2 -> 3 | {"(2,3)"} + 4 | 5 | arc 4 -> 5 | {"(4,5)"} +(7 rows) + +with recursive search_graph(f, t, label) as ( + select * from graph0 g + union distinct + select g.* + from graph0 g, search_graph sg + where g.f = sg.t +) search depth first by f, t set seq +select * from search_graph order by seq; +ERROR: SEARCH clause not supported with UNION DISTINCT +with recursive search_graph(f, t, label) as ( + select * from graph0 g + union all + select g.* + from graph0 g, search_graph sg + where g.f = sg.t +) search breadth first by f, t set seq +select * from search_graph order by seq; + f | t | label | seq +---+---+------------+--------- + 1 | 2 | arc 1 -> 2 | (0,1,2) + 1 | 3 | arc 1 -> 3 | (0,1,3) + 1 | 4 | arc 1 -> 4 | (0,1,4) + 2 | 3 | arc 2 -> 3 | (0,2,3) + 4 | 5 | arc 4 -> 5 | (0,4,5) + 2 | 3 | arc 2 -> 3 | (1,2,3) + 4 | 5 | arc 4 -> 5 | (1,4,5) +(7 rows) + +with recursive search_graph(f, t, label) as ( + select * from graph0 g + union distinct + select g.* + from graph0 g, search_graph sg + where g.f = sg.t +) search breadth first by f, t set seq +select * from search_graph order by seq; +ERROR: SEARCH clause not supported with UNION DISTINCT +-- various syntax errors +with recursive search_graph(f, t, label) as ( + select * from graph0 g + union all + select g.* + from graph0 g, search_graph sg + where g.f = sg.t +) search depth first by foo, tar set seq +select * from search_graph; +ERROR: search column "foo" not in WITH query column list +LINE 7: ) search depth first by foo, tar set seq + ^ +with recursive search_graph(f, t, label) as ( + select * from graph0 g + union all + select g.* + from graph0 g, search_graph sg + where g.f = sg.t +) search depth first by f, t set label +select * from search_graph; +ERROR: search sequence column name "label" already used in WITH query column list +LINE 7: ) search depth first by f, t set label + ^ +with recursive search_graph(f, t, label) as ( + select * from graph0 g + union all + select g.* + from graph0 g, search_graph sg + where g.f = sg.t +) search depth first by f, t, f set seq +select * from search_graph; +ERROR: search column "f" specified more than once +LINE 7: ) search depth first by f, t, f set seq + ^ +-- test ruleutils and view expansion +create temp view v_search as +with recursive search_graph(f, t, label) as ( + select * from graph0 g + union all + select g.* + from graph0 g, search_graph sg + where g.f = sg.t +) search depth first by f, t set seq +select f, t, label from search_graph; +select pg_get_viewdef('v_search'); + pg_get_viewdef +------------------------------------------------ + WITH RECURSIVE search_graph(f, t, label) AS (+ + SELECT g.f, + + g.t, + + g.label + + FROM graph0 g + + UNION ALL + + SELECT g.f, + + g.t, + + g.label + + FROM graph0 g, + + search_graph sg + + WHERE (g.f = sg.t) + + ) SEARCH DEPTH FIRST BY f, t SET seq + + SELECT search_graph.f, + + search_graph.t, + + search_graph.label + + FROM search_graph; +(1 row) + +select * from v_search; + 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 + 2 | 3 | arc 2 -> 3 + 4 | 5 | arc 4 -> 5 +(7 rows) + -- -- test cycle detection -- @@ -654,6 +796,297 @@ select * from search_graph order by path; 5 | 1 | arc 5 -> 1 | {"(5,1)","(1,4)","(4,5)","(5,1)"} | t (25 rows) +-- CYCLE clause +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 +select * from search_graph; + f | t | label | is_cycle | path +---+---+------------+----------+------------------------------------------- + 1 | 2 | arc 1 -> 2 | f | {"(1,2)"} + 1 | 3 | arc 1 -> 3 | f | {"(1,3)"} + 2 | 3 | arc 2 -> 3 | f | {"(2,3)"} + 1 | 4 | arc 1 -> 4 | f | {"(1,4)"} + 4 | 5 | arc 4 -> 5 | f | {"(4,5)"} + 5 | 1 | arc 5 -> 1 | f | {"(5,1)"} + 1 | 2 | arc 1 -> 2 | f | {"(5,1)","(1,2)"} + 1 | 3 | arc 1 -> 3 | f | {"(5,1)","(1,3)"} + 1 | 4 | arc 1 -> 4 | f | {"(5,1)","(1,4)"} + 2 | 3 | arc 2 -> 3 | f | {"(1,2)","(2,3)"} + 4 | 5 | arc 4 -> 5 | f | {"(1,4)","(4,5)"} + 5 | 1 | arc 5 -> 1 | f | {"(4,5)","(5,1)"} + 1 | 2 | arc 1 -> 2 | f | {"(4,5)","(5,1)","(1,2)"} + 1 | 3 | arc 1 -> 3 | f | {"(4,5)","(5,1)","(1,3)"} + 1 | 4 | arc 1 -> 4 | f | {"(4,5)","(5,1)","(1,4)"} + 2 | 3 | arc 2 -> 3 | f | {"(5,1)","(1,2)","(2,3)"} + 4 | 5 | arc 4 -> 5 | f | {"(5,1)","(1,4)","(4,5)"} + 5 | 1 | arc 5 -> 1 | f | {"(1,4)","(4,5)","(5,1)"} + 1 | 2 | arc 1 -> 2 | f | {"(1,4)","(4,5)","(5,1)","(1,2)"} + 1 | 3 | arc 1 -> 3 | f | {"(1,4)","(4,5)","(5,1)","(1,3)"} + 1 | 4 | arc 1 -> 4 | t | {"(1,4)","(4,5)","(5,1)","(1,4)"} + 2 | 3 | arc 2 -> 3 | f | {"(4,5)","(5,1)","(1,2)","(2,3)"} + 4 | 5 | arc 4 -> 5 | t | {"(4,5)","(5,1)","(1,4)","(4,5)"} + 5 | 1 | arc 5 -> 1 | t | {"(5,1)","(1,4)","(4,5)","(5,1)"} + 2 | 3 | arc 2 -> 3 | f | {"(1,4)","(4,5)","(5,1)","(1,2)","(2,3)"} +(25 rows) + +with recursive search_graph(f, t, label) as ( + select * from graph g + union distinct + 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 +select * from search_graph; +ERROR: CYCLE clause not supported with UNION DISTINCT +-- multiple CTEs +with recursive +graph(f, t, label) as ( + values (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') +), +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 +select f, t, label from search_graph; + 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 + 2 | 3 | arc 2 -> 3 + 4 | 5 | arc 4 -> 5 + 5 | 1 | arc 5 -> 1 + 1 | 4 | arc 1 -> 4 + 1 | 3 | arc 1 -> 3 + 1 | 2 | arc 1 -> 2 + 5 | 1 | arc 5 -> 1 + 1 | 4 | arc 1 -> 4 + 1 | 3 | arc 1 -> 3 + 1 | 2 | arc 1 -> 2 + 4 | 5 | arc 4 -> 5 + 2 | 3 | arc 2 -> 3 + 1 | 4 | arc 1 -> 4 + 1 | 3 | arc 1 -> 3 + 1 | 2 | arc 1 -> 2 + 4 | 5 | arc 4 -> 5 + 2 | 3 | arc 2 -> 3 + 5 | 1 | arc 5 -> 1 + 2 | 3 | arc 2 -> 3 +(25 rows) + +-- star expansion +with recursive a as ( + select 1 as b + union all + select * from a +) cycle b set c to true default false using p +select * from a; + b | c | p +---+---+----------- + 1 | f | {(1)} + 1 | t | {(1),(1)} +(2 rows) + +-- search+cycle +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 +) search depth first by f, t set seq + cycle f, t set is_cycle to true default false using path +select * from search_graph; + f | t | label | seq | is_cycle | path +---+---+------------+-------------------------------------------+----------+------------------------------------------- + 1 | 2 | arc 1 -> 2 | {"(1,2)"} | f | {"(1,2)"} + 1 | 3 | arc 1 -> 3 | {"(1,3)"} | f | {"(1,3)"} + 2 | 3 | arc 2 -> 3 | {"(2,3)"} | f | {"(2,3)"} + 1 | 4 | arc 1 -> 4 | {"(1,4)"} | f | {"(1,4)"} + 4 | 5 | arc 4 -> 5 | {"(4,5)"} | f | {"(4,5)"} + 5 | 1 | arc 5 -> 1 | {"(5,1)"} | f | {"(5,1)"} + 1 | 2 | arc 1 -> 2 | {"(5,1)","(1,2)"} | f | {"(5,1)","(1,2)"} + 1 | 3 | arc 1 -> 3 | {"(5,1)","(1,3)"} | f | {"(5,1)","(1,3)"} + 1 | 4 | arc 1 -> 4 | {"(5,1)","(1,4)"} | f | {"(5,1)","(1,4)"} + 2 | 3 | arc 2 -> 3 | {"(1,2)","(2,3)"} | f | {"(1,2)","(2,3)"} + 4 | 5 | arc 4 -> 5 | {"(1,4)","(4,5)"} | f | {"(1,4)","(4,5)"} + 5 | 1 | arc 5 -> 1 | {"(4,5)","(5,1)"} | f | {"(4,5)","(5,1)"} + 1 | 2 | arc 1 -> 2 | {"(4,5)","(5,1)","(1,2)"} | f | {"(4,5)","(5,1)","(1,2)"} + 1 | 3 | arc 1 -> 3 | {"(4,5)","(5,1)","(1,3)"} | f | {"(4,5)","(5,1)","(1,3)"} + 1 | 4 | arc 1 -> 4 | {"(4,5)","(5,1)","(1,4)"} | f | {"(4,5)","(5,1)","(1,4)"} + 2 | 3 | arc 2 -> 3 | {"(5,1)","(1,2)","(2,3)"} | f | {"(5,1)","(1,2)","(2,3)"} + 4 | 5 | arc 4 -> 5 | {"(5,1)","(1,4)","(4,5)"} | f | {"(5,1)","(1,4)","(4,5)"} + 5 | 1 | arc 5 -> 1 | {"(1,4)","(4,5)","(5,1)"} | f | {"(1,4)","(4,5)","(5,1)"} + 1 | 2 | arc 1 -> 2 | {"(1,4)","(4,5)","(5,1)","(1,2)"} | f | {"(1,4)","(4,5)","(5,1)","(1,2)"} + 1 | 3 | arc 1 -> 3 | {"(1,4)","(4,5)","(5,1)","(1,3)"} | f | {"(1,4)","(4,5)","(5,1)","(1,3)"} + 1 | 4 | arc 1 -> 4 | {"(1,4)","(4,5)","(5,1)","(1,4)"} | t | {"(1,4)","(4,5)","(5,1)","(1,4)"} + 2 | 3 | arc 2 -> 3 | {"(4,5)","(5,1)","(1,2)","(2,3)"} | f | {"(4,5)","(5,1)","(1,2)","(2,3)"} + 4 | 5 | arc 4 -> 5 | {"(4,5)","(5,1)","(1,4)","(4,5)"} | t | {"(4,5)","(5,1)","(1,4)","(4,5)"} + 5 | 1 | arc 5 -> 1 | {"(5,1)","(1,4)","(4,5)","(5,1)"} | t | {"(5,1)","(1,4)","(4,5)","(5,1)"} + 2 | 3 | arc 2 -> 3 | {"(1,4)","(4,5)","(5,1)","(1,2)","(2,3)"} | f | {"(1,4)","(4,5)","(5,1)","(1,2)","(2,3)"} +(25 rows) + +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 +) search breadth first by f, t set seq + cycle f, t set is_cycle to true default false using path +select * from search_graph; + f | t | label | seq | is_cycle | path +---+---+------------+---------+----------+------------------------------------------- + 1 | 2 | arc 1 -> 2 | (0,1,2) | f | {"(1,2)"} + 1 | 3 | arc 1 -> 3 | (0,1,3) | f | {"(1,3)"} + 2 | 3 | arc 2 -> 3 | (0,2,3) | f | {"(2,3)"} + 1 | 4 | arc 1 -> 4 | (0,1,4) | f | {"(1,4)"} + 4 | 5 | arc 4 -> 5 | (0,4,5) | f | {"(4,5)"} + 5 | 1 | arc 5 -> 1 | (0,5,1) | f | {"(5,1)"} + 1 | 2 | arc 1 -> 2 | (1,1,2) | f | {"(5,1)","(1,2)"} + 1 | 3 | arc 1 -> 3 | (1,1,3) | f | {"(5,1)","(1,3)"} + 1 | 4 | arc 1 -> 4 | (1,1,4) | f | {"(5,1)","(1,4)"} + 2 | 3 | arc 2 -> 3 | (1,2,3) | f | {"(1,2)","(2,3)"} + 4 | 5 | arc 4 -> 5 | (1,4,5) | f | {"(1,4)","(4,5)"} + 5 | 1 | arc 5 -> 1 | (1,5,1) | f | {"(4,5)","(5,1)"} + 1 | 2 | arc 1 -> 2 | (2,1,2) | f | {"(4,5)","(5,1)","(1,2)"} + 1 | 3 | arc 1 -> 3 | (2,1,3) | f | {"(4,5)","(5,1)","(1,3)"} + 1 | 4 | arc 1 -> 4 | (2,1,4) | f | {"(4,5)","(5,1)","(1,4)"} + 2 | 3 | arc 2 -> 3 | (2,2,3) | f | {"(5,1)","(1,2)","(2,3)"} + 4 | 5 | arc 4 -> 5 | (2,4,5) | f | {"(5,1)","(1,4)","(4,5)"} + 5 | 1 | arc 5 -> 1 | (2,5,1) | f | {"(1,4)","(4,5)","(5,1)"} + 1 | 2 | arc 1 -> 2 | (3,1,2) | f | {"(1,4)","(4,5)","(5,1)","(1,2)"} + 1 | 3 | arc 1 -> 3 | (3,1,3) | f | {"(1,4)","(4,5)","(5,1)","(1,3)"} + 1 | 4 | arc 1 -> 4 | (3,1,4) | t | {"(1,4)","(4,5)","(5,1)","(1,4)"} + 2 | 3 | arc 2 -> 3 | (3,2,3) | f | {"(4,5)","(5,1)","(1,2)","(2,3)"} + 4 | 5 | arc 4 -> 5 | (3,4,5) | t | {"(4,5)","(5,1)","(1,4)","(4,5)"} + 5 | 1 | arc 5 -> 1 | (3,5,1) | t | {"(5,1)","(1,4)","(4,5)","(5,1)"} + 2 | 3 | arc 2 -> 3 | (4,2,3) | f | {"(1,4)","(4,5)","(5,1)","(1,2)","(2,3)"} +(25 rows) + +-- various syntax errors +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 foo, tar set is_cycle to true default false 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... + ^ +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 55 using path +select * from search_graph; +ERROR: CYCLE types boolean and integer cannot be matched +LINE 7: ) cycle f, t set is_cycle to true default 55 using path + ^ +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 f to true default false using path +select * from search_graph; +ERROR: cycle column name "f" already used in WITH query column list +LINE 7: ) cycle f, t set f to true default false using path + ^ +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, f set is_cycle to true default false using path +select * from search_graph; +ERROR: cycle column "f" specified more than once +LINE 7: ) cycle f, t, f set is_cycle to true default false using pat... + ^ +-- test ruleutils and view expansion +create temp view v_cycle 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 +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 + + FROM search_graph; +(1 row) + +select * from v_cycle; + 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) + -- -- test multiple WITH queries -- diff --git a/src/test/regress/sql/with.sql b/src/test/regress/sql/with.sql index f85645efde..af6329165c 100644 --- a/src/test/regress/sql/with.sql +++ b/src/test/regress/sql/with.sql @@ -295,6 +295,96 @@ CREATE TEMPORARY TABLE tree( SELECT t1.id, t2.path, t2 FROM t AS t1 JOIN t AS t2 ON (t1.id=t2.id); +-- SEARCH clause + +create temp table graph0( f int, t int, label text ); + +insert into graph0 values + (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'); + +with recursive search_graph(f, t, label) as ( + select * from graph0 g + union all + select g.* + from graph0 g, search_graph sg + where g.f = sg.t +) search depth first by f, t set seq +select * from search_graph order by seq; + +with recursive search_graph(f, t, label) as ( + select * from graph0 g + union distinct + select g.* + from graph0 g, search_graph sg + where g.f = sg.t +) search depth first by f, t set seq +select * from search_graph order by seq; + +with recursive search_graph(f, t, label) as ( + select * from graph0 g + union all + select g.* + from graph0 g, search_graph sg + where g.f = sg.t +) search breadth first by f, t set seq +select * from search_graph order by seq; + +with recursive search_graph(f, t, label) as ( + select * from graph0 g + union distinct + select g.* + from graph0 g, search_graph sg + where g.f = sg.t +) search breadth first by f, t set seq +select * from search_graph order by seq; + +-- various syntax errors +with recursive search_graph(f, t, label) as ( + select * from graph0 g + union all + select g.* + from graph0 g, search_graph sg + where g.f = sg.t +) search depth first by foo, tar set seq +select * from search_graph; + +with recursive search_graph(f, t, label) as ( + select * from graph0 g + union all + select g.* + from graph0 g, search_graph sg + where g.f = sg.t +) search depth first by f, t set label +select * from search_graph; + +with recursive search_graph(f, t, label) as ( + select * from graph0 g + union all + select g.* + from graph0 g, search_graph sg + where g.f = sg.t +) search depth first by f, t, f set seq +select * from search_graph; + +-- test ruleutils and view expansion +create temp view v_search as +with recursive search_graph(f, t, label) as ( + select * from graph0 g + union all + select g.* + from graph0 g, search_graph sg + where g.f = sg.t +) search depth first by f, t set seq +select f, t, label from search_graph; + +select pg_get_viewdef('v_search'); + +select * from v_search; + -- -- test cycle detection -- @@ -327,6 +417,126 @@ CREATE TEMPORARY TABLE tree( ) select * from search_graph order by path; +-- CYCLE clause + +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 +select * from search_graph; + +with recursive search_graph(f, t, label) as ( + select * from graph g + union distinct + 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 +select * from search_graph; + +-- multiple CTEs +with recursive +graph(f, t, label) as ( + values (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') +), +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 +select f, t, label from search_graph; + +-- star expansion +with recursive a as ( + select 1 as b + union all + select * from a +) cycle b set c to true default false using p +select * from a; + +-- search+cycle +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 +) search depth first by f, t set seq + cycle f, t set is_cycle to true default false using path +select * from search_graph; + +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 +) search breadth first by f, t set seq + cycle f, t set is_cycle to true default false using path +select * from search_graph; + +-- various syntax errors +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 foo, tar set is_cycle to true default false using path +select * from search_graph; + +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 55 using path +select * from search_graph; + +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 f to true default false using path +select * from search_graph; + +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, f set is_cycle to true default false using path +select * from search_graph; + +-- test ruleutils and view expansion +create temp view v_cycle 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 +select f, t, label from search_graph; + +select pg_get_viewdef('v_cycle'); + +select * from v_cycle; + -- -- test multiple WITH queries -- base-commit: f13f2e484172a1c865cd067796cee3568467dd51 -- 2.28.0