Possible internal server error on refresh statistics operations due to dropped database objects

Detail name	Value
Changelog Number	5764
Type	Bug
Status	Resolved
Affected Versions	EXASOL 6.0.4
Fix Versions	EXASOL 6.0.8
Resolution Date	2018-02-19

Problem Description

Refresh and drop statistics operations are often recommended after a version upgrade or migration of an Exasol database. These operations can be called on tables, schemas or the entire database, using following statements:

ANALYZE DATABASE REFRESH STATISTICS;
ANALYZE SCHEMA schema REFRESH STATISTICS;
ANALYZE SCHAMAS schema1, schema2 REFRESH STATISTICS;
ANALYZE TABLE table REFRESH STATISTICS;
ANALYZE TABLES table1, table2 REFRESH STATISTICS;

These operations may lead to an internal server error when objects in those schemas have recently been dropped or replaced.

Circumstances

Reproducing this issue reliably is not possible. It is probable to occur when objects have been recently dropped explicitly or implicitly using "CREATE OR REPLACE TABLE ..." statements.

Workaround

This error can be avoided by manually calling refresh or drop statistics operations on individual tables instead of on entire schemas or databases.