SAP Knowledge Base Article - Preview

2098977 - ORDER BY clause causing query to take longer - SAP ASE

Symptom

  • You are running a query with a UNION ALL clasue and an ORDER BY clause.
  • Without ORDER BY the query runs fast.
  • When appending ORDER BY on a column that is already indexed, the query takes considerably longer to execute.
  • When ORDER BY is used, the query plan shows that the optimizer is spending a lot of time in sorting of a worktable.
  • ASE is configured with the optimization goal "allrows_oltp".

Read more...

Environment

SAP Adaptive Server Enterprise (ASE) 15.x

Product

SAP Adaptive Server Enterprise 15.7 ; Sybase Adaptive Server Enterprise 15.0 ; Sybase Adaptive Server Enterprise 15.5

Keywords

allrows_mix, allrows_dss, join, nested-loop, hash-joins, merge-joins, optgoal, performance , KBA , BC-SYB-ASE , Sybase ASE Database Platform (non Business Suite) , Problem

About this page

This is a preview of a SAP Knowledge Base Article. Click more to access the full version on SAP ONE Support launchpad (Login required).

Search for additional results

Visit SAP Support Portal's SAP Notes and KBA Search.