![]() ![]() Even distribution is the default distribution style for Redshift. In particular, moving data from one node will have a major impact on network traffic.Īmazon Redshift supports three different types of table distribution styles: Even, Key and All. The cost of data redistribution can be substantial, and often it will slow down query performance. This can happen for two reasons - first when performing joins or aggregates and second when trying to distribute the workload uniformly among the nodes in the cluster. This means Redshift query execution engine may need to move or redistribute data from one node or slice to another physically during the runtime. Redshift's query optimizer determines where the block of data need to reside to execute the most optimized query. Cost of data redistributionĪmazon Redshift query execution engine ships with an MPP-aware query optimizer. For instance, if a query is performing join over two tables, to avoid the redistribution of data, data from two tables can be co-located by planning an appropriate distribution style. This is accomplished by locating or co-locating the data where it needs to be before the query is executed. A key objective is to avoid the data redistribution during query execution or runtime. ![]() In a nutshell, table's distribution style dictates how the data is distributed across Redshift node and slices. When using Amazon Redshift, distribution style plays an important role in optimising the table design for best performance. ![]()
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