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How Does Impala Process Join Queries For Large Tables? |
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Answer» Impala utilizes multiple strategies to ALLOW joins between tables and result SETS of various sizes. When joining a large table with a small one, the data from the small table is transmitted to each node for intermediate processing. When joining TWO large tables, the data from one of the tables is DIVIDED into pieces, and each node processes only selected pieces. Impala utilizes multiple strategies to allow joins between tables and result sets of various sizes. When joining a large table with a small one, the data from the small table is transmitted to each node for intermediate processing. When joining two large tables, the data from one of the tables is divided into pieces, and each node processes only selected pieces. |
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