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Posted to commits@druid.apache.org by GitBox <gi...@apache.org> on 2021/04/08 21:36:42 UTC
[GitHub] [druid] jihoonson opened a new pull request #11083: Fix CAST being ignored when aggregating on strings after cast
jihoonson opened a new pull request #11083:
URL: https://github.com/apache/druid/pull/11083
### Description
Currently, `CAST` is ignored in the query plan when you use certain aggregators on string columns after case. Taking a query, `SELECT APPROX_QUANTILE_DS(CAST(dim1 as DOUBLE), 0.01) FROM foo`, as a example, Druid creates a query plan like below.
```json
{
"queryType" : "timeseries",
"dataSource" : {
"type" : "table",
"name" : "foo"
},
"intervals" : {
"type" : "intervals",
"intervals" : [ "-146136543-09-08T08:23:32.096Z/146140482-04-24T15:36:27.903Z" ]
},
"descending" : false,
"virtualColumns" : [ ],
"granularity" : {
"type" : "all"
},
"aggregations" : [ {
"type" : "DoublesSketchAggregatorFactory",
"name" : "a0:agg",
"fieldName" : "dim1",
"k" : 128
} ],
"postAggregations" : [ {
"type" : "DoublesSketchToQuantilePostAggregator",
"name" : "a0",
"field" : {
"type" : "fieldAccess",
"name" : "a0:agg",
"fieldName" : "a0:agg"
},
"fraction" : 0.009999999776482582
} ]
}
```
As a result, this query always returns `0.0` because strings cannot be casted to numbers implicitly. This PR fixes this issue by keeping `CAST` when it casts from string to a number.
This PR additionally fixes NPE in `ApproximateHistogramBufferAggregator` when the input column has nulls. Finally, some sqlAggregator tests are refactored to use help functions in `BaseCalciteQueryTest`.
<hr>
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This PR has:
- [x] been self-reviewed.
- [ ] using the [concurrency checklist](https://github.com/apache/druid/blob/master/dev/code-review/concurrency.md) (Remove this item if the PR doesn't have any relation to concurrency.)
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- [ ] added integration tests.
- [ ] been tested in a test Druid cluster.
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[GitHub] [druid] clintropolis merged pull request #11083: Fix CAST being ignored when aggregating on strings after cast
Posted by GitBox <gi...@apache.org>.
clintropolis merged pull request #11083:
URL: https://github.com/apache/druid/pull/11083
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