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FAQ: I have loaded Raster Data into Oracle, and the performance is slow

Question

I have loaded Raster Data into Oracle, and the performance is slow

Answer

When loading Raster data, the last step in the process must always be to Analyze the data. This will update the Oracle database statistics that are used by the Oracle Cost Based Optimizer to work out the best execution plan for the SQL. Failing to update the database statistics after the load and pyramid build will result in poor performance.

Analyze the Raster dataset by either right-clicking the raster dataset in ArcCatalog and selecting Analyze, or use RDBMS tools to update all the tables that make up the Raster dataset.

Check the statistics have been updated using the following SQL:

SELECT table_name, last_analyzed
FROM user_tables;

Note: At the ArcGIS 8.2 release, to Analyze an embedded raster catalog, use RDBMS tools. Oracle Enterprise Manager is a good tool for this.

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