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From James Heather <james.heat...@mendeley.com>
Subject Re: Explain plan over primary key column
Date Wed, 30 Sep 2015 14:38:58 GMT
I don't see why it wouldn't be able to use the index for that.

In any case, if that's what "explain" is telling you, I think you can 
trust it...

James

On 30/09/15 15:36, Sumit Nigam wrote:
> Thanks so much James ...
>
> I am sorry to be asking so many questions ... But last one -
>
> When I -
> EXPLAIN  SELECT ID, TEXT FROM EXP  WHERE ID > 5 AND ID < 10
>
> here TEXT is not a part of PK, then also I get the same plan - RANGE 
> SCAN OVER EXP [6] - [10]
>
> Which I suppose just means that rowkey index is still used. I thought 
> that global indexes are only used when all columns in the query are a 
> part of it.
>
> Sorry again.
> Sumit
>
> ------------------------------------------------------------------------
> *From:* James Heather <james.heather@mendeley.com>
> *To:* user@phoenix.apache.org
> *Sent:* Wednesday, September 30, 2015 7:58 PM
> *Subject:* Re: Explain plan over primary key column
>
> Yup
>
>
>
> On 30/09/15 15:25, Sumit Nigam wrote:
>> Thanks James.
>>
>> So, if I did a range lookup like - EXPLAIN SELECT ID FROM EXP WHERE 
>> ID > 5 AND ID < 10
>>  then I get  .... RANGE SCAN OVER EXP [6] - [10]
>>
>> Is that indication enough that PK/ index is used?
>>
>> ------------------------------------------------------------------------
>> *From:* James Heather <james.heather@mendeley.com> 
>> <mailto:james.heather@mendeley.com>
>> *To:* user@phoenix.apache.org <mailto:user@phoenix.apache.org>
>> *Sent:* Wednesday, September 30, 2015 7:49 PM
>> *Subject:* Re: Explain plan over primary key column
>>
>> You're asking for every single row of the table, so nothing's going 
>> to avoid a full scan. The index wouldn't help.
>>
>>
>>
>> On 30/09/15 15:18, Sumit Nigam wrote:
>>> Hi,
>>>
>>> I have a table as:
>>>
>>> CREATE TABLE EXP (ID BIGINT NOT NULL PRIMARY KEY, TEXT VARCHAR);
>>>
>>> If I explain the select:
>>>
>>> EXPLAIN SELECT ID FROM EXP;
>>>
>>> Then it shows CLIENT 1-CHUNK PARALLEL 1-WAY FULL SCAN OVER EXP ....
>>>
>>> I assume it still uses rowkey. Or is it should have shown using 
>>> rowkey in explain plan?
>>>
>>> Also, is it a good idea to declare VARCHAR(n) vs plain VARCHAR? Does 
>>> it save some space?
>>>
>>> Thanks,
>>> Sumit
>>
>>
>>
>
>
>


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