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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
This commit is contained in:
Peter Eisentraut
2021-02-01 13:54:59 +01:00
parent bb513b364b
commit 3696a600e2
28 changed files with 2301 additions and 33 deletions

View File

@ -409,6 +409,44 @@ _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_STRING_FIELD(cycle_path_column);
READ_LOCATION_FIELD(location);
READ_OID_FIELD(cycle_mark_type);
READ_INT_FIELD(cycle_mark_typmod);
READ_OID_FIELD(cycle_mark_collation);
READ_OID_FIELD(cycle_mark_neop);
READ_DONE();
}
/*
* _readCommonTableExpr
*/
@ -421,6 +459,8 @@ _readCommonTableExpr(void)
READ_NODE_FIELD(aliascolnames);
READ_ENUM_FIELD(ctematerialized, CTEMaterialize);
READ_NODE_FIELD(ctequery);
READ_NODE_FIELD(search_clause);
READ_NODE_FIELD(cycle_clause);
READ_LOCATION_FIELD(location);
READ_BOOL_FIELD(cterecursive);
READ_INT_FIELD(cterefcount);
@ -2653,6 +2693,10 @@ 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))