Greenplum Skew and How to Avoid it

Greenplum is a MPP shared nothing environment. Data is spread across the many segments located on the multiple segment hosts. If the data is distributed properly, no two segments in the system have same data. The even distribution of the data is determined by the column(s) provided in the DISTRIBUTED BY clause. Greenplum skew is the table situation that degrade the performance. System distributes the rows with same distribution values to same segment. Hence, the more the unique value in the distribution column, the better. In case if the data…

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