postgres.git / summary / log / commit / refs

commit    a01a3d931e5a14d60eec75f7945d5e66ff9cc575
Author:   Alvaro Herrera <alvherre@alvh.no-ip.org>
Date:     Thu Oct 12 15:23:47 2017 +0000
First released in: 11.0, 10.1

    Infer functional dependency past RelabelType
    
    Vars hidden within a RelabelType would not be detected as compatible
    with some functional dependency.  Repair by properly ignoring the
    RelabelType.
    
    Author: David Rowley
    Reviewed-by: Tomas Vondra
    Discussion: https://postgr.es/m/CAKJS1f-y-UEy=rsBXynBOgiW1fKMr_LVoYSGL9QOc36mLEC-ww@mail.gmail.com


 src/backend/statistics/dependencies.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/src/backend/statistics/dependencies.c b/src/backend/statistics/dependencies.c
index 2e7c0ad6ba6..9756fb83c0c 100644
--- a/src/backend/statistics/dependencies.c
+++ b/src/backend/statistics/dependencies.c
@@ -792,6 +792,14 @@ dependency_is_compatible_clause(Node *clause, Index relid, AttrNumber *attnum)
 
 		var = (varonleft) ? linitial(expr->args) : lsecond(expr->args);
 
+		/*
+		 * We may ignore any RelabelType node above the operand.  (There won't
+		 * be more than one, since eval_const_expressions() has been applied
+		 * already.)
+		 */
+		if (IsA(var, RelabelType))
+			var = (Var *) ((RelabelType *) var)->arg;
+
 		/* We only support plain Vars for now */
 		if (!IsA(var, Var))
 			return false;


[parent: 7cde649ab150]