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Improving Query Performance

NuoDB tries to optimize query execution when it chooses table join order and indexes for the query plan. However, query execution might still be less than optimal and if that is the case then you can try any of the following alternatives to improve query performance:

Caution: SYSTEM.QUERYSTATS, SYSTEM.CONNECTIONS, SYSTEM.INDEXSTATISTICS, SYSTEM.INDEXPREFIXSTATISTICS, SYSTEM.INDEXHISTOGRAMS, and SYSTEM.INDEXHISTOGRAMBUCKETS are pseudo system tables. This means they contain information that is dynamically generated by NuoDB processes and presented as a SQL table. Client applications should never contain code that accesses pseudo system tables as they are subject to, and furthermore likely to, change from release to release.

See the following topics:

Identifying Historical Slow Queries Using System Tables

Identifying Currently Running Slow Queries Using System Tables

Obtaining SQL Elapsed Time Report

Running ANALYZE to Obtain Index Statistics

Example of Debugging a Slow Query

Using Optimizer Hints