diff --git a/src/backend/access/common/relation.c b/src/backend/access/common/relation.c
index 38b356b8239..ad32bd13d5f 100644
--- a/src/backend/access/common/relation.c
+++ b/src/backend/access/common/relation.c
@@ -59,7 +59,9 @@ relation_open(Oid relationId, LOCKMODE lockmode)
 	r = RelationIdGetRelation(relationId);
 
 	if (!RelationIsValid(r))
-		elog(ERROR, "could not open relation with OID %u", relationId);
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("could not open relation with OID %u", relationId)));
 
 	/*
 	 * If we didn't get the lock ourselves, assert that caller holds one,
@@ -113,7 +115,9 @@ try_relation_open(Oid relationId, LOCKMODE lockmode)
 	r = RelationIdGetRelation(relationId);
 
 	if (!RelationIsValid(r))
-		elog(ERROR, "could not open relation with OID %u", relationId);
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("could not open relation with OID %u", relationId)));
 
 	/* If we didn't get the lock ourselves, assert that caller holds one */
 	Assert(lockmode != NoLock ||
diff --git a/src/backend/catalog/objectaddress.c b/src/backend/catalog/objectaddress.c
index 703754a8123..655eeb1b500 100644
--- a/src/backend/catalog/objectaddress.c
+++ b/src/backend/catalog/objectaddress.c
@@ -4314,7 +4314,10 @@ getObjectDescription(const ObjectAddress *object, bool missing_ok)
 			}
 
 		default:
-			elog(ERROR, "unsupported object class: %u", object->classId);
+			ereport(ERROR,
+					(errcode(ERRCODE_WRONG_OBJECT_TYPE),
+					 errmsg("unsupported object class: %u", object->classId)));
+
 	}
 
 	/* an empty buffer is equivalent to no object found */
diff --git a/src/backend/commands/tablecmds.c b/src/backend/commands/tablecmds.c
index 9b911310f05..4226115ec84 100644
--- a/src/backend/commands/tablecmds.c
+++ b/src/backend/commands/tablecmds.c
@@ -9693,6 +9693,7 @@ ATPrepAddPrimaryKey(List **wqueue, Relation rel, AlterTableCmd *cmd,
 				tup = findNotNullConstraint(childrelid, strVal(column));
 				if (!tup)
 					ereport(ERROR,
+							errcode(ERRCODE_INVALID_TABLE_DEFINITION),
 							errmsg("column \"%s\" of table \"%s\" is not marked NOT NULL",
 								   strVal(column), get_rel_name(childrelid)));
 				/* verify it's good enough */
diff --git a/src/backend/parser/parse_coerce.c b/src/backend/parser/parse_coerce.c
index d3240f4b265..46e66990ac1 100644
--- a/src/backend/parser/parse_coerce.c
+++ b/src/backend/parser/parse_coerce.c
@@ -541,8 +541,12 @@ coerce_type(ParseState *pstate, Node *node,
 		return (Node *) r;
 	}
 	/* If we get here, caller blew it */
-	elog(ERROR, "failed to find conversion function from %s to %s",
-		 format_type_be(inputTypeId), format_type_be(targetTypeId));
+	ereport(ERROR,
+			(errcode(ERRCODE_CANNOT_COERCE),
+			 errmsg("failed to find conversion function from %s to %s",
+					format_type_be(inputTypeId), format_type_be(targetTypeId))));
+
+
 	return NULL;				/* keep compiler quiet */
 }
 
diff --git a/src/backend/parser/parse_utilcmd.c b/src/backend/parser/parse_utilcmd.c
index 640e1c4f5a4..abfe449f895 100644
--- a/src/backend/parser/parse_utilcmd.c
+++ b/src/backend/parser/parse_utilcmd.c
@@ -797,8 +797,10 @@ transformColumnDefinition(CreateStmtContext *cxt, ColumnDef *column)
 					if (constraint->conname &&
 						notnull_constraint->conname &&
 						strcmp(notnull_constraint->conname, constraint->conname) != 0)
-						elog(ERROR, "conflicting not-null constraint names \"%s\" and \"%s\"",
-							 notnull_constraint->conname, constraint->conname);
+						ereport(ERROR,
+								errcode(ERRCODE_INVALID_TABLE_DEFINITION),
+								errmsg("conflicting not-null constraint names \"%s\" and \"%s\"",
+									   notnull_constraint->conname, constraint->conname));
 
 					if (notnull_constraint->is_no_inherit != constraint->is_no_inherit)
 						ereport(ERROR,
diff --git a/src/backend/storage/ipc/shmem.c b/src/backend/storage/ipc/shmem.c
index 228871d2525..4491aabd9a6 100644
--- a/src/backend/storage/ipc/shmem.c
+++ b/src/backend/storage/ipc/shmem.c
@@ -1119,7 +1119,9 @@ pg_get_shmem_allocations_numa(PG_FUNCTION_ARGS)
 	Size	   *nodes;
 
 	if (pg_numa_init() == -1)
-		elog(ERROR, "libnuma initialization failed or NUMA is not supported on this platform");
+		ereport(ERROR,
+				(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+				 errmsg("libnuma initialization failed or NUMA is not supported on this platform")));
 
 	InitMaterializedSRF(fcinfo, 0);
 
diff --git a/src/backend/utils/adt/acl.c b/src/backend/utils/adt/acl.c
index 25cd5d0296b..2385c1ebbe9 100644
--- a/src/backend/utils/adt/acl.c
+++ b/src/backend/utils/adt/acl.c
@@ -996,7 +996,9 @@ acldefault_sql(PG_FUNCTION_ARGS)
 			objtype = OBJECT_TYPE;
 			break;
 		default:
-			elog(ERROR, "unrecognized object type abbreviation: %c", objtypec);
+			ereport(ERROR,
+					(errcode(ERRCODE_WRONG_OBJECT_TYPE),
+					 errmsg("unrecognized object type abbreviation: %c", objtypec)));
 	}
 
 	PG_RETURN_ACL_P(acldefault(objtype, owner));
diff --git a/src/backend/utils/adt/float.c b/src/backend/utils/adt/float.c
index fd7a6587132..2a33bc37e81 100644
--- a/src/backend/utils/adt/float.c
+++ b/src/backend/utils/adt/float.c
@@ -2982,7 +2982,10 @@ check_float8_array(ArrayType *transarray, const char *caller, int n)
 		ARR_DIMS(transarray)[0] != n ||
 		ARR_HASNULL(transarray) ||
 		ARR_ELEMTYPE(transarray) != FLOAT8OID)
-		elog(ERROR, "%s: expected %d-element float8 array", caller, n);
+		ereport(ERROR,
+				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+				 errmsg("%s: expected %d-element float8 array", caller, n)));
+
 	return (float8 *) ARR_DATA_PTR(transarray);
 }
 
diff --git a/src/backend/utils/adt/rangetypes.c b/src/backend/utils/adt/rangetypes.c
index 84d71761c1b..cedfa458c89 100644
--- a/src/backend/utils/adt/rangetypes.c
+++ b/src/backend/utils/adt/rangetypes.c
@@ -336,7 +336,9 @@ get_range_io_data(FunctionCallInfo fcinfo, Oid rngtypid, IOFuncSelector func)
 												   sizeof(RangeIOData));
 		cache->typcache = lookup_type_cache(rngtypid, TYPECACHE_RANGE_INFO);
 		if (cache->typcache->rngelemtype == NULL)
-			elog(ERROR, "type %u is not a range type", rngtypid);
+			ereport(ERROR,
+					(errcode(ERRCODE_DATATYPE_MISMATCH),
+					 errmsg("type %u is not a range type", rngtypid)));
 
 		/* get_type_io_data does more than we need, but is convenient */
 		get_type_io_data(cache->typcache->rngelemtype->type_id,
diff --git a/src/backend/utils/adt/timestamp.c b/src/backend/utils/adt/timestamp.c
index 9c17ba2f905..06d238024e5 100644
--- a/src/backend/utils/adt/timestamp.c
+++ b/src/backend/utils/adt/timestamp.c
@@ -1489,7 +1489,10 @@ AdjustIntervalForTypmod(Interval *interval, int32 typmod,
 			/* fractional-second rounding will be dealt with below */
 		}
 		else
-			elog(ERROR, "unrecognized interval typmod: %d", typmod);
+			ereport(ERROR,
+					(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+					 errmsg("unrecognized interval typmod: %d", typmod)));
+
 
 		/* Need to adjust sub-second precision? */
 		if (precision != INTERVAL_FULL_PRECISION)
diff --git a/src/pl/plpgsql/src/pl_gram.y b/src/pl/plpgsql/src/pl_gram.y
index 5e14a2d7302..98410ce6fd6 100644
--- a/src/pl/plpgsql/src/pl_gram.y
+++ b/src/pl/plpgsql/src/pl_gram.y
@@ -393,7 +393,10 @@ comp_option		: '#' K_OPTION K_DUMP
 						else if (strcmp($3, "off") == 0)
 							plpgsql_curr_compile->print_strict_params = false;
 						else
-							elog(ERROR, "unrecognized print_strict_params option %s", $3);
+							ereport(ERROR,
+									(errcode(ERRCODE_SYNTAX_ERROR),
+									 errmsg("unrecognized print_strict_params option %s", $3)));
+
 					}
 				| '#' K_VARIABLE_CONFLICT K_ERROR
 					{
diff --git a/src/test/regress/regress.c b/src/test/regress/regress.c
index c72ee31cdce..2cd4e17b869 100644
--- a/src/test/regress/regress.c
+++ b/src/test/regress/regress.c
@@ -1494,7 +1494,9 @@ test_pglz_decompress(PG_FUNCTION_ARGS)
 	dlen = pglz_decompress(source, slen, VARDATA(result),
 						   rawsize, check_complete);
 	if (dlen < 0)
-		elog(ERROR, "pglz_decompress failed");
+		ereport(ERROR,
+				(errcode(ERRCODE_DATA_CORRUPTED),
+				 errmsg("pglz_decompress failed")));
 
 	SET_VARSIZE(result, dlen + VARHDRSZ);
 	PG_RETURN_BYTEA_P(result);