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Hi Julian,


yes, it occurs in solr-adapter. we need to get the DISTINCT status for translating to solr's query plan. So can I skip this optimization? If I can't, I will make a JIRA case.


Thanks,


Haochao Zhuang




------------------ 原始邮件 ------------------
发件人: "Julian Hyde"<jhyde@xxxxxxxxxx>;
发送时间: 2018年11月14日(星期三) 中午11:36
收件人: "dev"<dev@xxxxxxxxxxxxxxxxxx>;
抄送: "大明"<zteny@xxxxxxxxxxx>; 
主题: Re: count(distinct col) can't recognize distinct



Can you log a JIRA case? This is specific to the Solr adapter, yes? If so, make that clear in the JIRA case.

Julian


> On Nov 13, 2018, at 7:29 PM, Haisheng Yuan <h.yuan@xxxxxxxxxxxxxxx> wrote:
> 
> The plan is correct for the following query:
> 
> select channel, count(distinct version) from daming group by channel
> 76:SolrAggregate(group=[{0}], EXPR$1=[COUNT($1)])
>  74:SolrAggregate(group=[{4, 7}])
>    0:SolrTableScan(table=[[test03.loc:2181/dmsolr, daming]])
> 
> It will first get group by channel and version, then group by channel. the count will be the number of distinct versions. It is an optimization for single aggregation with count distinct.
> 
> 
> Thanks ~
> Haisheng Yuan
> ------------------------------------------------------------------
> 发件人:大明<zteny@xxxxxxxxxxx>
> 日 期:2018年11月14日 11:20:41
> 收件人:dev<dev@xxxxxxxxxxxxxxxxxx>
> 主 题:回复: count(distinct col) can't recognize distinct
> 
> Maybe I need to show more detail about this.
> I printed the explaination using `input.explain(pw)`.
> 
> 
> select channel, count(distinct version), sum(amount) from daming group by channel
> 500:SolrAggregate(group=[{4}], EXPR$1=[COUNT(DISTINCT $7)], EXPR$2=[SUM($0)])
>  0:SolrTableScan(table=[[test03.loc:2181/dmsolr, daming]])
> 
> 
> select channel, count(distinct version) from daming group by channel
> 76:SolrAggregate(group=[{0}], EXPR$1=[COUNT($1)])
>  74:SolrAggregate(group=[{4, 7}])
>    0:SolrTableScan(table=[[test03.loc:2181/dmsolr, daming]])
> 
> 
> 
> Thanks!
> 
> 
> Best Regards
> haochao.zhuang
> 
> 
> ------------------ 原始邮件 ------------------
> 发件人: "大明"<zteny@xxxxxxxxxxx>;
> 发送时间: 2018年11月13日(星期二) 晚上10:43
> 收件人: "dev"<dev@xxxxxxxxxxxxxxxxxx>;
> 
> 主题: 回复: count(distinct col) can't recognize distinct
> 
> 
> 
> 
> 
> 
> 
> Dears
> 
> 
> i catch it in the solr adaptor. it is implemented by solr as elasticsearch adaptor.
> 
> 
> case a: correct
> select a, count(distinct b) from tbl group by a;  
> 
> 
> case b: incorrect
> 1. select a, count(distinct b) from tbl where c = 'c' group by a;
> 
> 2. select a, count(distinct b), max(c)  from tbl group by a; 
> 
> 
> 
> 
> attached solr's code
> 
> 
> public void implement(Implementor implementor) {
>    implementor.visitChild(0, getInput());
> 
> 
>    final List<String> inNames = SolrRules.solrFieldNames(getInput().getRowType());
>    for(Pair<AggregateCall, String> namedAggCall : getNamedAggCalls()) {
> 
> 
>      AggregateCall aggCall = namedAggCall.getKey();
> 
> 
>      Pair<String, String> metric = toSolrMetric(implementor, aggCall, inNames);
>      implementor.addReverseAggMapping(namedAggCall.getValue(), metric.getKey().toLowerCase(Locale.ROOT)+"("+metric.getValue()+")");
>      implementor.addMetricPair(namedAggCall.getValue(), metric.getKey(), metric.getValue());
>    }
>    ...
> }
> 
> 
> Best Regards
> Haochao Zhuang
> 
> 
> 
> 
> 
> 
> ------------------ 原始邮件 ------------------
> 发件人: "Michael Mior"<mmior@xxxxxxxxxx>;
> 发送时间: 2018年11月13日(星期二) 晚上9:35
> 收件人: "dev"<dev@xxxxxxxxxxxxxxxxxx>;
> 
> 主题: Re: count(distinct col) can't recognize distinct
> 
> 
> 
> Can you give a specific example of a query that doesn't do what you expect
> it to do?
> 
> --
> Michael Mior
> mmior@xxxxxxxxxx
> 
> 
> Le mar. 13 nov. 2018 à 07:56, 大明 <zteny@xxxxxxxxxxx> a écrit :
> 
>> Hi Guys:
>> 
>> 
>> I got a question why it can't recognize DISTINCT tag on COUNT(DISTINCT
>> col) aggregation function sometimes.
>> 
>> 
>> but it is not problem when my sql query statement have WHEN clause or one
>> more aggregation functions.
>> 
>> 
>> Best Regards
>> Haochao Zhuang