IS NULL in combination with views can cause an internal server errors in rare cases

Detail name	Value
Changelog Number	5495
Type	Bug
Status	Resolved
Affected Versions	EXASOL 6.0.6
Fix Versions	EXASOL 6.0.7
Resolution Date	2017-12-19

The combination of IS NULL, views and joins can lead to an internal server error in Exasol.

How To Reproduce

DROP SCHEMA TEST CASCADE;
CREATE SCHEMA TEST; 

CREATE OR REPLACE TABLE T1(C0 INT);
CREATE OR REPLACE TABLE T2(C1 INT);
CREATE OR REPLACE VIEW V1 AS SELECT	T2.C1 FROM T2 RIGHT JOIN T1 ON TRUE;

WITH
	V2 AS(
		SELECT
			CASE WHEN(C1 IS NULL) THEN 1 ELSE 0 END AS C2
		FROM
			V1
	)
SELECT
	*
FROM
		(
			SELECT
				*
			FROM
				V2
		)
	LEFT JOIN
		(
			SELECT
				*
			FROM
				V2
			WHERE
				C2 = 1
		)
	ON
		TRUE;

Error:

[40005] Successfully reconnected after internal server error, transaction was rolled back.

Workaround
Disable the view optimization with the parameter:

-disableViewOptimization=1