Month: July 2014
Optimization issues: Cross column correlation
UPDATE Sept. 2023: For more recent information about planner statistics, see the PostgreSQL documentation about extended statistics, or this blog about CREATE STATISTICS. You can also find out more recent info in this blog about Improving Group By with Create Statistics. The blog post below about cross correlation has been preserved for reference. Planner estimates […]
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Detecting wrong planner estimates
In 99% of all cases the PostgreSQL planner does a perfect job to optimize your queries and to make sure that you enjoy high performance and low response times. The infrastructure ensuring this is both sophisticated as well as robust. However, there are some corner cases which can turn out to be quite nasty. In […]
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