How To: Set dbtune.sde parameters for Oracle 8i spatial objects storage


What is the recommended dbtune.sde file for Oracle 8i spatial object storing in ArcSDE 8.0.1? Which value for SDO_GEOMETRY, SDO_LEVEL, SDE_NUMTILES values is recommended to store 30000 features tables as Oracle 8i Spatial Objects storing?


As stated in the new Configuration and Tuning Guide, and in the sample dbtune.sde file included with the 8.0.1 for Oracle 8i installation, GEOMETRY_STORAGE should be set to SDO_GEOMETRY.

For SDO_LEVEL, SDO_NUMTILES (and any others) a trial and error process must be used. Different installs and different complexity of features within each dataset will give different results for the spatial index. Number of features is not important other than for how much disk space the Oracle spatial index takes up.

Since SDE does not control the spatial indexing of SDO/Spatial Type layers, Oracle tools must be used to determine the appropriate values. These functions may be helpful, particularly the first two:

SDO_TUNE.ESTIMATE_INDEX_PERFORMANCE - Estimates the spatial index selectivity.

SDO_TUNE.ESTIMATE_TILING_LEVEL - Determines an appropriate tiling level for creating fixed-size index tiles.

SDO_TUNE.AVERAGE_MBR - Calculates the average minimum bounding rectangle for geometries in a layer.

SDO_TUNE.ESTIMATE_TILING_TIME - Estimates the tiling time for a layer, in seconds.

SDO_TUNE.EXTENT_OF - Determines the minimum bounding rectangle of the data in a layer.

SDO_TUNE.HISTOGRAM_ANALYSIS - Calculates statistical histograms for a spatial layer.

SDO_TUNE.MIX_INFO - Calculates geometry type information for a spatial layer, such as the percentage of each geometry type.

Please consult the Oracle Spatial documentation for the proper use of these functions