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| author | Peter Eisentraut <peter@eisentraut.org> | 2021-02-01 13:54:59 +0100 |
|---|---|---|
| committer | Peter Eisentraut <peter@eisentraut.org> | 2021-02-01 14:32:51 +0100 |
| commit | 3696a600e2292d43c00949ddf0352e4ebb487e5b (patch) | |
| tree | 11f19c8c9e5757c44b8da02d0e1f7b41f8ec5f13 /src/backend/nodes/nodeFuncs.c | |
| parent | bb513b364b4fe31574574c8d0afbb2255268b321 (diff) | |
| download | postgresql-3696a600e2292d43c00949ddf0352e4ebb487e5b.tar.gz postgresql-3696a600e2292d43c00949ddf0352e4ebb487e5b.zip | |
SEARCH and CYCLE clauses
This adds the SQL standard feature that adds the SEARCH and CYCLE
clauses to recursive queries to be able to do produce breadth- or
depth-first search orders and detect cycles. These clauses can be
rewritten into queries using existing syntax, and that is what this
patch does in the rewriter.
Reviewed-by: Vik Fearing <vik@postgresfriends.org>
Reviewed-by: Pavel Stehule <pavel.stehule@gmail.com>
Discussion: https://www.postgresql.org/message-id/flat/db80ceee-6f97-9b4a-8ee8-3ba0c58e5be2@2ndquadrant.com
Diffstat (limited to 'src/backend/nodes/nodeFuncs.c')
| -rw-r--r-- | src/backend/nodes/nodeFuncs.c | 42 |
1 files changed, 41 insertions, 1 deletions
diff --git a/src/backend/nodes/nodeFuncs.c b/src/backend/nodes/nodeFuncs.c index 6be19916fce..49357ac5c2d 100644 --- a/src/backend/nodes/nodeFuncs.c +++ b/src/backend/nodes/nodeFuncs.c @@ -1566,6 +1566,12 @@ 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; @@ -1909,6 +1915,7 @@ expression_tree_walker(Node *node, case T_NextValueExpr: case T_RangeTblRef: case T_SortGroupClause: + case T_CTESearchClause: /* primitive node types with no expression subnodes */ break; case T_WithCheckOption: @@ -2148,6 +2155,16 @@ expression_tree_walker(Node *node, return true; } break; + case T_CTECycleClause: + { + CTECycleClause *cc = (CTECycleClause *) node; + + if (walker(cc->cycle_mark_value, context)) + return true; + if (walker(cc->cycle_mark_default, context)) + return true; + } + break; case T_CommonTableExpr: { CommonTableExpr *cte = (CommonTableExpr *) node; @@ -2156,7 +2173,13 @@ expression_tree_walker(Node *node, * Invoke the walker on the CTE's Query node, so it can * recurse into the sub-query if it wants to. */ - return walker(cte->ctequery, context); + if (walker(cte->ctequery, context)) + return true; + + if (walker(cte->search_clause, context)) + return true; + if (walker(cte->cycle_clause, context)) + return true; } break; case T_List: @@ -2615,6 +2638,7 @@ expression_tree_mutator(Node *node, case T_NextValueExpr: case T_RangeTblRef: case T_SortGroupClause: + case T_CTESearchClause: return (Node *) copyObject(node); case T_WithCheckOption: { @@ -3019,6 +3043,17 @@ expression_tree_mutator(Node *node, return (Node *) newnode; } break; + case T_CTECycleClause: + { + CTECycleClause *cc = (CTECycleClause *) node; + CTECycleClause *newnode; + + FLATCOPY(newnode, cc, CTECycleClause); + MUTATE(newnode->cycle_mark_value, cc->cycle_mark_value, Node *); + MUTATE(newnode->cycle_mark_default, cc->cycle_mark_default, Node *); + return (Node *) newnode; + } + break; case T_CommonTableExpr: { CommonTableExpr *cte = (CommonTableExpr *) node; @@ -3031,6 +3066,10 @@ expression_tree_mutator(Node *node, * recurse into the sub-query if it wants to. */ MUTATE(newnode->ctequery, cte->ctequery, Node *); + + MUTATE(newnode->search_clause, cte->search_clause, CTESearchClause *); + MUTATE(newnode->cycle_clause, cte->cycle_clause, CTECycleClause *); + return (Node *) newnode; } break; @@ -3913,6 +3952,7 @@ raw_expression_tree_walker(Node *node, } break; case T_CommonTableExpr: + /* search_clause and cycle_clause are not interesting here */ return walker(((CommonTableExpr *) node)->ctequery, context); default: elog(ERROR, "unrecognized node type: %d", |