Record the proper typmod for an index expression column.

tglsfdc · tglsfdc · commit 39b0c7681e46 · 2014-04-26T12:22:09.000-04:00
We should use exprTypmod() to extract the typmod of the expression, instead of just blindly storing -1. This seems to have been an aboriginal oversight in commit fc8d970 which introduced general-expression indexes. The consequences are only cosmetic at present, since the index machinery doesn't really look at typmod for index columns; but still it seems best to describe the column type as precisely as we can. Per off-list complaint from Thomas Fanghaenel.
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
@@ -389,7 +389,7 @@ ConstructTupleDescriptor(Relation heapRelation,
 			to->attalign = typeTup->typalign;
 			to->attstattarget = -1;
 			to->attcacheoff = -1;
-			to->atttypmod = -1;
+			to->atttypmod = exprTypmod(indexkey);
 			to->attislocal = true;
 			to->attcollation = collationObjectId[i];
 
