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Posted to reviews@iotdb.apache.org by GitBox <gi...@apache.org> on 2020/03/08 14:39:11 UTC
[GitHub] [incubator-iotdb] Ring-k opened a new pull request #894:
[IOTDB-476] Improve the ExpressionOptimizer
Ring-k opened a new pull request #894: [IOTDB-476] Improve the ExpressionOptimizer
URL: https://github.com/apache/incubator-iotdb/pull/894
Accidentally, previous pull request failed to be merged into master branch. Here is the details of the pull request.
Some logic in ExpressionOptimizer is modified to make the optimizer generate more efficient expression. For example, before the modification, s1 > 10 or time < 1 will be tranformed to
`ORExpression ( SingleSeriesExpression(s1 , value >10) ORExpression( SingleSeriesExpression(s1 , time <10), SingleSeriesExpression(s2 , time <10) ) )`
With the new logic, the query will be transformed to
`ORExpression ( SingleSeriesExpression(s1 , value >10 or time <10) SingleSeriesExpression(s2 , time <10) )`
With less SingleSeriesExpressions, the query can be executed more efficiently. Experiments shows that, if we have 3 devices, each containing 3 sensors, and the query is t<4838 or d2.s2>0.5, the latency decreases around 10%.
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[GitHub] [incubator-iotdb] qiaojialin merged pull request #894: [IOTDB-476]
Improve the ExpressionOptimizer
Posted by GitBox <gi...@apache.org>.
qiaojialin merged pull request #894: [IOTDB-476] Improve the ExpressionOptimizer
URL: https://github.com/apache/incubator-iotdb/pull/894
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