Aggregated Fact Table is the summarized table (or materialized view) propagated from the atomic transaction fact table. The aggregated fact table contains fewer rows from the summarization. Query performance gain can be obtained through it when less details are required in some user analysis. We may build multiple aggregated fact tables in different levels (Daily and Monthly).The aggregated fact tables and their atomic transaction fact table can be co-exists and accessible by users. Some aggregate navigation technologies are available in some DB optimizers / BI Tools (e.g. aggregate aware in BO) to pick the best table for user query.
Friday, October 30, 2020
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Extract: Performance Tips
Below listed some common performance tips for extract queries. Extract required columns only and specify in the query, avoid select * Extrac...
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Extract is the first step in the ETL process which obtains data from the source systems. This is our first question. How much data we need t...
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If we are using dimensional data model, make sure to build atomic grain base fact tables. It is true that they takes more space and performs...
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Below listed some common performance tips for extract queries. Extract required columns only and specify in the query, avoid select * Extrac...
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