Hi, all
ExpressionOptimizer is improved to generate more efficient expressions. For
example, before the modification, the query 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%.
-------------------
Yuyuan KANG
School of Software, Tsinghua University
在2020-02-14 09:53:42，Yuyuan [email protected]写道：
Hi, all
I'm working on issue [IOTDB-476], "Improve the ExpressionOptimizer".
-------------------
Yuyuan KANG
School of Software, Tsinghua University
