hawq-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From James Campbell <jacampb...@pivotal.io>
Subject Re: A question of HAWQ (update/delete)
Date Wed, 13 Jul 2016 16:40:44 GMT
One way an “delete” can be implemented in Hawq is to use partition-exchange.  It is ugly,
but it provides away of implement more of a batch update/delete.

In order to do this, you need partitioned tables.   For a delete, you select everything in
the target partition out less the row(s) that you don’t want into a new partitioned table.
  The new table has the correct data in it. You use the alter table command to execute a
partition exchange.

You can us this general approach to perform an update.

Generally, it is not a good design practice to use deletes with big data or in data warehouses.
 We don’t want to be trying to implement an OLTP system.  However, if there is a business
case to do this, it can be done in more of a batch fashion.

— 
Jim Campbell
jacampbell@pivotal.io <mailto:jacampbell@pivotal.io>
O: 703-753-5970
M: 571-247-6511

On July 13, 2016 at 12:18:19 PM, Wales Wang (wormwang@yahoo.com.invalid) wrote:

Actian vectorH can support update , delete on HDFS  

Wales Wang  

在 2016-7-13,下午11:15,Vineet Goel <vvineet@apache.org> 写道:  

> Update and Delete is not supported yet, but it's in the future plan. There  
> is a JIRA on it I believe:  
>  
> https://issues.apache.org/jira/browse/HAWQ-304  
>  
> Out of curiosity, what specific scenario are you trying to solve that  
> requires update/delete ?  
>  
>  
> -Vineet  
>  
>  
>  
> On Tue, Jul 12, 2016 at 7:10 PM, jinzhy <jinzhy@neusoft.com> wrote:  
>  
>> hello everybody,  
>>  
>> Can HAWQ or Pivotal HD support 'delete' or 'update' operation in  
>> HDFS now?I can only create append only table in my computer。  
>>  
>>  
>>  
>>  
>>  
>>  
>>  
>>  
>>  
>> ---------------------------------------------------------------------------------------------------
 
>> Confidentiality Notice: The information contained in this e-mail and any  
>> accompanying attachment(s)  
>> is intended only for the use of the intended recipient and may be  
>> confidential and/or privileged of  
>> Neusoft Corporation, its subsidiaries and/or its affiliates. If any reader  
>> of this communication is  
>> not the intended recipient, unauthorized use, forwarding, printing,  
>> storing, disclosure or copying  
>> is strictly prohibited, and may be unlawful.If you have received this  
>> communication in error,please  
>> immediately notify the sender by return e-mail, and delete the original  
>> message and all copies from  
>> your system. Thank you.  
>>  
>> ---------------------------------------------------------------------------------------------------
 
>>  

Mime
  • Unnamed multipart/alternative (inline, None, 0 bytes)
View raw message