Sometimes natural skew can become a huge problem, causing bad join performance. The Partial Duplication & Partial Redistribution (PDPR)  feature on Teradata 14 (and above) helps to reduce this issue, but will not always be able to detect all possible applications (for example, if statistics are not revealing the skewed values). If you are stuck

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Dealing with data skew can be considered a principal activity in Teradata performance optimization. Although skew on table level usually can be avoided by choosing a proper Primary Index, skew arising during query execution is often a major issue (so-called spool skew). Spool skew is often emerging when joining tables (or spools). On a typical Teradata

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