Improve the error message when creating an empty range partition.

The previous message didn't mention the name of the table or the
bounds.  Put the table name in the primary error message and the
bounds in the detail message.

Amit Langote, changed slightly by me.  Suggestions on the exac
phrasing from Tom Lane, David G. Johnston, and Dean Rasheed.

Discussion: http://postgr.es/m/CA+Tgmoae6bpwVa-1BMaVcwvCCeOoJ5B9Q9-RHWo-1gJxfPBZ5Q@mail.gmail.com

2 files changed, 51 insertions, 43 deletions

diff --git a/src/backend/catalog/partition.c b/src/backend/catalog/partition.c
index dcc7f8af27c..0e4b343ab28 100644
--- a/src/backend/catalog/partition.c
+++ b/src/backend/catalog/partition.c
@@ -722,10 +722,16 @@ check_new_partition_bound(char *relname, Relation parent,
 				 */
 				if (partition_rbound_cmp(key, lower->datums, lower->kind, true,
 										 upper) >= 0)
+				{
 					ereport(ERROR,
 							(errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
-							 errmsg("cannot create range partition with empty range"),
-							 parser_errposition(pstate, spec->location)));
+							 errmsg("empty range bound specified for partition \"%s\"",
+									relname),
+							 errdetail("Specified lower bound %s is greater than or equal to upper bound %s.",
+								get_range_partbound_string(spec->lowerdatums),
+								get_range_partbound_string(spec->upperdatums)),
+								parser_errposition(pstate, spec->location)));
+				}
 
 				if (partdesc->nparts > 0)
 				{
diff --git a/src/backend/utils/adt/ruleutils.c b/src/backend/utils/adt/ruleutils.c
index d83377d1d88..0faa0204cef 100644
--- a/src/backend/utils/adt/ruleutils.c
+++ b/src/backend/utils/adt/ruleutils.c
@@ -8722,47 +8722,9 @@ get_rule_expr(Node *node, deparse_context *context,
 							   list_length(spec->lowerdatums) ==
 							   list_length(spec->upperdatums));
 
-						appendStringInfoString(buf, "FOR VALUES FROM (");
-						sep = "";
-						foreach(cell, spec->lowerdatums)
-						{
-							PartitionRangeDatum *datum =
-							castNode(PartitionRangeDatum, lfirst(cell));
-
-							appendStringInfoString(buf, sep);
-							if (datum->kind == PARTITION_RANGE_DATUM_MINVALUE)
-								appendStringInfoString(buf, "MINVALUE");
-							else if (datum->kind == PARTITION_RANGE_DATUM_MAXVALUE)
-								appendStringInfoString(buf, "MAXVALUE");
-							else
-							{
-								Const	   *val = castNode(Const, datum->value);
-
-								get_const_expr(val, context, -1);
-							}
-							sep = ", ";
-						}
-						appendStringInfoString(buf, ") TO (");
-						sep = "";
-						foreach(cell, spec->upperdatums)
-						{
-							PartitionRangeDatum *datum =
-							castNode(PartitionRangeDatum, lfirst(cell));
-
-							appendStringInfoString(buf, sep);
-							if (datum->kind == PARTITION_RANGE_DATUM_MINVALUE)
-								appendStringInfoString(buf, "MINVALUE");
-							else if (datum->kind == PARTITION_RANGE_DATUM_MAXVALUE)
-								appendStringInfoString(buf, "MAXVALUE");
-							else
-							{
-								Const	   *val = castNode(Const, datum->value);
-
-								get_const_expr(val, context, -1);
-							}
-							sep = ", ";
-						}
-						appendStringInfoString(buf, ")");
+						appendStringInfo(buf, "FOR VALUES FROM %s TO %s",
+							get_range_partbound_string(spec->lowerdatums),
+							get_range_partbound_string(spec->upperdatums));
 						break;
 
 					default:
@@ -10943,3 +10905,43 @@ flatten_reloptions(Oid relid)
 
 	return result;
 }
+
+/*
+ * get_one_range_partition_bound_string
+ *		A C string representation of one range partition bound
+ */
+char *
+get_range_partbound_string(List *bound_datums)
+{
+	deparse_context context;
+	StringInfo	buf = makeStringInfo();
+	ListCell   *cell;
+	char	   *sep;
+
+	memset(&context, 0, sizeof(deparse_context));
+	context.buf = buf;
+
+	appendStringInfoString(buf, "(");
+	sep = "";
+	foreach(cell, bound_datums)
+	{
+		PartitionRangeDatum *datum =
+		castNode(PartitionRangeDatum, lfirst(cell));
+
+		appendStringInfoString(buf, sep);
+		if (datum->kind == PARTITION_RANGE_DATUM_MINVALUE)
+			appendStringInfoString(buf, "MINVALUE");
+		else if (datum->kind == PARTITION_RANGE_DATUM_MAXVALUE)
+			appendStringInfoString(buf, "MAXVALUE");
+		else
+		{
+			Const	   *val = castNode(Const, datum->value);
+
+			get_const_expr(val, &context, -1);
+		}
+		sep = ", ";
+	}
+	appendStringInfoString(buf, ")");
+
+	return buf->data;
+}