About Memory-Consuming Features - Teradata Database

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About Memory-Consuming Features

Certain features may require more memory in order to show their optimal performance benefit. Of particular mention are:

  • Array INSERT
  • Compression
  • Cylinder read
  • Geospatial data type
  • Global and Persistent Data (GLOP)
  • Hash joins and product joins
  • Join index
  • Large objects (LOBs)
  • Row and column partitioning
  • Table functions
  • Stored procedures
  • User-defined functions (UDFs)
  • XML data type
  • 1 MB response buffer
  • 1 MB data blocks
  • Larger than 1 MB plan cache
  • Performance gains from implementing these features may be countered by their impact on memory usage. In turn, you may experience more segment swaps and incur additional swap physical disk I/O. To counter this, you can lower the FSG cache percent to ensure that 135 MB per AMP is allocated in OS memory.

    Lowering the FSG cache percent may cause fewer cache hits on table data and instead cause a different type of additional physical disk I/O. In general, additional I/O on table data is a lesser performance issue than swapping I/O, but it can still have an impact on performance.