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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/rewrite/rewriteHandler.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/rewrite/rewriteHandler.c')
| -rw-r--r-- | src/backend/rewrite/rewriteHandler.c | 18 |
1 files changed, 18 insertions, 0 deletions
diff --git a/src/backend/rewrite/rewriteHandler.c b/src/backend/rewrite/rewriteHandler.c index 0c7508a0d8b..0672f497c6b 100644 --- a/src/backend/rewrite/rewriteHandler.c +++ b/src/backend/rewrite/rewriteHandler.c @@ -38,6 +38,7 @@ #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" @@ -2080,6 +2081,23 @@ fireRIRrules(Query *parsetree, List *activeRIRs) 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... */ |