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vipenkoul 8 posts Joined 02/10
19 Feb 2010
Query troubleshooting

How can one start troubleshooting a query and subsequently provide a solution in Teradata.I am looking for best practices.1. How to identify.2. What to look for in terms of metrics (system & SQL level)3. What methods are available and which one to use in which scenario.4. How to replicate or confirm the problem5. How to fix and test a solution.6. Last and but not the least "Best practices for writing SQLs, what to consider from performance prespective in Teradata".Thanks

jim 3 posts Joined 05/09
23 Mar 2010

The first thing you want to do is to run an explain on the query. This will tell you each step the parsing engine will take when formulating a plan to execute the query. The second step to improve performance would be to collect statistics for any columns in the query that are involved in a join or a filter (where clause). Then run the explain again after collecting statistics and you can see the difference.

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