IBM® Informix® 12.10

Estimate your spatial data

The total amount of space you need for spatial data is equal to the size of spatial tables plus the size of the spatial indexes.

The table size approximations discussed here should be within 100 MB accuracy for large tables; to make estimates of greater precision, refer to the IBM Informix Performance Guide.

Further tuning information is available at http://www.ibm.com/software/data/informix/blades/spatial/.

To estimate the amount of space you need for spatial data, add the results of the following calculations:

  1. Estimating the storage space for the table
    The total size of a spatial table is equal to the column sizes plus the dbspace overhead size multiplied by the number of rows.
  2. Estimating the smart large object storage space
    A spatial data value is stored in row if the value is less than or equal to 930 bytes. However, if the value is greater than 930 bytes, only a pointer of 64 bytes is stored in row. This pointer refers to the smart large object in which the actual data is stored.
  3. Estimating the size of spatial indexes
    You can calculate the size of your spatial indexes based on the size of your spatial columns and dbspace overhead space size.
Parent topic: Spatial Data User's Guide

Examples exchange | Troubleshooting

To find the PDF, see Publications for the IBM Informix 12.10 family of products.
For the release notes, documentation notes, and/or machine notes, see the Release Notes page.