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Jialin Qiao closed IOTDB-476. ----------------------------- > Improve the ExpressionOptimizer > ------------------------------- > > Key: IOTDB-476 > URL: https://issues.apache.org/jira/browse/IOTDB-476 > Project: Apache IoTDB > Issue Type: Improvement > Components: Core/TsFile > Reporter: Jialin Qiao > Assignee: Yuyuan KANG > Priority: Minor > Labels: pull-request-available > Time Spent: 20m > Remaining Estimate: 0h > > Suppose there are two time series: s1, s2 and a sql has a predicate : s1>10 > or time < 10 > > In the ExpressionOptimizer, the time < 10 will be unfolded with all series, > then combined with s1>10. Finally, the predicate will be transformed into a > tree structure: > ORExpression ( > SingleSeriesExpression(s1, value>10) > ORExpression( > SingleSeriesExpression(s1, time>10), > SingleSeriesExpression(s2, time>10) > ) > ) > We will construct a SeriesReader for each SingleSeriesExpression in the > ITimeGenerator. > This expression could be optimized into the following: > ORExpression ( > SingleSeriesExpression(s1, value>10 or time>10) > SingleSeriesExpression(s2, time>10) > ) > -- This message was sent by Atlassian Jira (v8.3.4#803005)