![]() Join tables from single and multiple databases Important: Data from splits cannot be used for Joing tables but can be used for blending. You can split data from the Data pane, or right-click: Transform -> Split. Tableau will only split fields it's told to do so. Why? Denormalization, you cannot touch the schema, etc.Īutomatic split happens when tableau can guess what kind of data is inside,ĭata Split cannot happen automagicaly. When? Sometimes your data has fields encoded inside string fields. This works with queries with the same LOD !! Understand how to use Automatic & Custom Split Tries to combine this multiple queryes into (just) one. If the same query is needeed in the same dashboard in several sheets, Tableau How? Combining queries together and using the results. Looks at all of dashboard queries and tries to eliminate any redundant queries. Warning: when the cache is invalidated, it will need to re-parse the file again, so it's a good idea to maka an extract unless the data is really tiny or can change unexpectedly. With extenal query caching Tableau doesn't need to parse a whole excel file to show some data. Tableau will cache data in memory / disk to avoid to ask ("go to the network") or parse data that won't have changed.Ī good example of this is a file-based data. This means that query operations on data extracts can run up to N times faster in Tableau 9 (where N is the number of cores in the machine). ![]() By default, the maximum degree of parallelism is (number of available logical processors) / 2. The data engine can now run aggregations in parallel, splitting the work across multiple cores. Tableau will use multiple cores where possible. No data about SSE4.2, AVG, or using GPUs to do this. Now tableau uses SIMD instructions (SSE4.1) to make calculations, thus better filling theĭata and execution pipeline of the processor. Why? would anyone like to limit the number of connections for datasources, joins, etc?īecause it might be a) starving other processes that access the datasource, or b) licensing issues. The level of paralelism is configurable on the 'connection-configs.xml' file (located in the Tableau instalation dir), see If we're using data from different data sources, Tableau will make queries in parallel without waiting one datasource query to finish before it makes the second query. Tableau will perform queries in parallel whenever possible. This is covered in the !(product documentation (for desktop)) Understand Performance Optimization Parallel query Source: Data Connections Understand how to connect to Tableau Server It makes sense to see the total/max/min under the point of view of a Dimension.īy default, Tableau will interpret numerical fields as Measures. Hint: If it makes sense to add it up, it's likely a measure.ĭimension: The stuff you use to ask questions. Tableau Desktop 10 Qualified Associate - Exam OutlineĮxam notes with links to questions, and solutions thatĮxemplify what's needed / asked in the Tableau 10 QA Exam.
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