how to improve the query perfoemance in teradata.with example?and how explain this in interview?please forward answer
Answer Posted / tdguy
Performance tuning increases with experience. Some tips
are: Analyze the plan displayed by TD. This would give
enough information about the query, data and performance.
Check for confidence levels. Try to identify the type of
joins. Avoid product, cartesian product and nested joins.
1. try to avoid unnecessary joins 2. Try to join using
unique value columns 3. collect stats 4. Use secondary
index appropriately 5. Use join index, if necessary 6.
Split the query, if necessary.
Again, see the plan and repeat the steps.
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