hbase-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Nick Dimiduk <ndimi...@gmail.com>
Subject Re: Struggles around Cell#getType()
Date Sun, 29 Oct 2017 17:28:53 GMT
On Fri, Oct 27, 2017 at 9:58 AM, Josh Elser <elserj@apache.org> wrote:

> Re-reading https://issues.apache.org/jira/browse/HBASE-8693 that Sergey
> pointed out, I more think that the maybe getType() was misintepreted from
> what Nick originally meant it to be. Maybe intentional, maybe not.

The classes under o.a.h.h.types are for helping users building applications
to represent their application data in HBase byte arrays. See the overview
in the package description [0]. One uses implementations of
o.a.h.h.types.DataType to encode values that can then be stored in
o.a.h.h.Cells -- as the row, the column qualifier, or column value. The
type of the Cell is its use within the KeyValue storage engine that is
HBase while the DataType describes a means of getting some Java object
value into or out of a byte array.


On 10/27/17 7:29 AM, Chia-Ping Tsai wrote:
>> The CellBuilder#Data type is introduced to make sure all components used
>> to builder cell are IA.Public.
>> bq. Best as I can tell, Cell#getType() should be deprecated
>> As i see it, the Cell#getType, #getTimestamp, #getSequenceId, and #getTag
>> should be deprecated as these methods is some kind of internal info of
>> storage engine. As a key-value store, the key  consisting of row, family,
>> and qualifier is enough to the general purpose. Other fields belong to the
>> specific storage engine, and they should not be in the Cell which is our
>> "frontline" interface of data.
>> On 2017-10-27 06:40, Josh Elser <elserj@apache.org> wrote:
>>> Hiya,
>>> (Background: see HBASE-19002)
>>> In trying to write some example Observers, I found myself in a pickle:
>>> how do I tell if a Cell is a Put?
>>> * Cell#getType() returns a byte which corresponds to a KeyValue.Type
>>> * KeyValue.Type has API to convert a byte to Type
>>> * KeyValue (and thus KeyValue.Type) is IA.Private
>>> * DataType o.a.h.h.typesDataType _appears to me_ to be the replacement
>>> for the KeyValue.Type
>>> Best as I can tell, Cell#getType() should be deprecated and we should
>>> have some kind of API (method on Cell or CellUtil) which returns a
>>> DataType instead of Type. The details of the byte and the KeyValue.Type
>>> should be hidden inside the implementation.
>>> My hunch is that this is an accidental omission, but Stack recommended
>>> that I "ask the class" ;). What have I missed? I think this is trivial
>>> to fix; obviously, I don't want to make a fix if I just didn't look hard
>>> enough.
>>> Thanks!
>>> - Josh

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