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SQL Anywhere 12.0.0 » UltraLite - Database Management and Reference » Using UltraLite databases » UltraLite performance and optimization


Managing temporary tables

In general, the optimizer always tries to avoid creating temporary tables to return query results because the entire temporary table must be populated before the first row can be returned. If an index exists, the optimizer tries to use the index first and only creates a temporary table as a last resort.

It is difficult to anticipate whether an index you have created avoids the necessity for a temporary table. Therefore, you should always check the plans for a query to ensure the indexes you have created are actually being used by the UltraLite query optimizer.

 See also

Using direct page scans
Reverting to primary key index order