如这个查询计划所示,不止一个散列表的键可以被下推来过滤事实表的行。
As this query plan shows, keys from more than one hash table build can be pushed down to filter rows of the fact table.
下推散列连接的主要目的是减少处理的事实表行数,这样可以探测每个散列表。
The primary purpose of a push-down hash join is to reduce number of rows processed from the fact table, which probes each of the hash tables.
星型连接计划中,数据库服务器在维度表中构建散列表的同时从维度表中下推键来过滤事实表。
In a star join plan, the database server pushes down keys from a dimension table to filter the fact table at the same time as it builds the hash table on the dimension table.
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