Schema-qualify internal queries used by ANALYZE.

To avoid being confused by a user-created function called "sum".

Fixes github issue #4185.

src/backend/commands/analyze.c

@@ -1694,13 +1694,13 @@ analyzeEstimateReltuplesRelpages(Oid relationOid, float4 *relTuples, float4 *rel
 
 		if (GpPolicyFetch(CurrentMemoryContext, singleOid)->ptype == POLICYTYPE_ENTRY)
 		{
-			appendStringInfo(&sqlstmt, "select sum(gp_statistics_estimate_reltuples_relpages_oid(c.oid))::float4[] "
-					"from pg_class c where c.oid=%d", singleOid);
+			appendStringInfo(&sqlstmt, "select pg_catalog.sum(pg_catalog.gp_statistics_estimate_reltuples_relpages_oid(c.oid))::pg_catalog.float4[] "
+					"from pg_catalog.pg_class c where c.oid=%d", singleOid);
 		}
 		else
 		{
-			appendStringInfo(&sqlstmt, "select sum(gp_statistics_estimate_reltuples_relpages_oid(c.oid))::float4[] "
-					"from gp_dist_random('pg_class') c where c.oid=%d", singleOid);
+			appendStringInfo(&sqlstmt, "select pg_catalog.sum(pg_catalog.gp_statistics_estimate_reltuples_relpages_oid(c.oid))::pg_catalog.float4[] "
+					"from pg_catalog.gp_dist_random('pg_catalog.pg_class') c where c.oid=%d", singleOid);
 		}
 
 		if (SPI_OK_CONNECT != SPI_connect())
@@ -1758,13 +1758,13 @@ analyzeEstimateIndexpages(Relation onerel, Relation indrel, BlockNumber *indexPa
 
 	if (GpPolicyFetch(CurrentMemoryContext, RelationGetRelid(onerel))->ptype == POLICYTYPE_ENTRY)
 	{
-		appendStringInfo(&sqlstmt, "select sum(gp_statistics_estimate_reltuples_relpages_oid(c.oid))::float4[] "
-						 "from pg_class c where c.oid=%d", RelationGetRelid(indrel));
+		appendStringInfo(&sqlstmt, "select pg_catalog.sum(pg_catalog.gp_statistics_estimate_reltuples_relpages_oid(c.oid))::pg_catalog.float4[] "
+						 "from pg_catalog.pg_class c where c.oid=%d", RelationGetRelid(indrel));
 	}
 	else
 	{
-		appendStringInfo(&sqlstmt, "select sum(gp_statistics_estimate_reltuples_relpages_oid(c.oid))::float4[] "
-						 "from gp_dist_random('pg_class') c where c.oid=%d", RelationGetRelid(indrel));
+		appendStringInfo(&sqlstmt, "select pg_catalog.sum(pg_catalog.gp_statistics_estimate_reltuples_relpages_oid(c.oid))::pg_catalog.float4[] "
+						 "from pg_catalog.gp_dist_random('pg_catalog.pg_class') c where c.oid=%d", RelationGetRelid(indrel));
 	}
 
 	if (SPI_OK_CONNECT != SPI_connect())