2353544 - SAP IQ 16 query performance degradation when selecting a NULL AS column name in a VIEW | SAP Knowledge Base Article

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2353544 - SAP IQ 16 query performance degradation when selecting a NULL AS column name in a VIEW

Symptom

  • Queries using table VIEW's that JOIN multiple tables together via UNION ALL's
  • Missing column definitions for tables in the view are defined using NULL AS <column name>
  • Queries affected referencing the NULL AS defined column may see a performance degradation of up to 15x slower
  • Query plan comparisons between a query referencing a NULL AS column and one that does not shows the faster query uses a HASH PUSH DOWN JOIN and the slower uses JOIN HASH

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Environment

  • SAP IQ 15.x and 16.x  systems on all platforms

Product

SAP IQ 16.0

Keywords

iq16, slow, deadlock, degradation, sybase table_view, tableview , KBA , BC-SYB-IQ , Sybase IQ , Problem

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