Excessive page faults slow down long running queries

Detail name	Value
Changelog Number	5368
Type	Improvement
Status	Resolved
Fix Versions	EXASOL 6.0.7
Resolution Date	2018-08-28

Problem Description

Long running queries with many joins or large aggregations allocate a lot of session heap memory. This was caused by a library used in Exasol which produced lots of page faults in session heap memory management. This resulted in high system time usage and hence losses of effective processing resources for queries.

Improvement

The library usage was refined and the negative effects cleaned out.
Part of the improvement introduces a possible automatic reduction of internal job vector sizes, further decreasing memory consumption of queries with many joins.

This new job size reduction can be disabled by the following parameter

-targetPipeJobSize=0

Workaround

There is no workaround.