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From Jaanai Zhang <cloud.pos...@gmail.com>
Subject Re: column mapping schema decoding
Date Thu, 27 Dec 2018 07:21:59 GMT
The actual column name and encoded qualifier number are stored in
SYSTEM.CATALOG
table, the field names are COLUMN_NAME(string) and COLUMN_QUALIFIER(binary)
respectively, QualifierEncodingScheme can be used to decode/encode
COLUMN_QUALIFIER, but this is a little complicated process.

For your scenario, maybe use the original column is better.




----------------------------------------
   Jaanai Zhang
   Best regards!



Shawn Li <shawnlijob@gmail.com> 于2018年12月27日周四 上午7:17写道:

> Hi Pedro,
>
> Thanks for reply. Can you explain a little bit more? For example, if we
> use COLUMN_ENCODED_BYTES = 1,How is the following table DDL converted to
> numbered column qualifier in Hbase? (such as A.population maps which
> number, B.zipcode Map to which number in Hbase)
>
> CREATE TABLE IF NOT EXISTS us_population (
>       state CHAR(2) NOT NULL,
>       city VARCHAR NOT NULL,
>       A.population BIGINT,
>       A.type CHAR,
>       B.zipcode CHAR(5),
>       B.quantity INT CONSTRAINT my_pk PRIMARY KEY (state, city));
>
>
> Thanks,
> Shawn
>
> On Wed, Dec 26, 2018 at 6:00 PM Pedro Boado <pboado@apache.org> wrote:
>
>> Hi,
>>
>> Column mapping is stored in SYSTEM.CATALOG table . There is only one
>> column mapping strategy with between 1 to 4 bytes to be used to represent
>> column number. Regardless of encoded column size, column name lookup
>> strategy remains the same.
>>
>> Hope it helps,
>>
>> Pedro.
>>
>>
>>
>> On Wed, 26 Dec 2018, 23:00 Shawn Li <shawnlijob@gmail.com wrote:
>>
>>> Hi,
>>>
>>> Phoenix 4.10 introduced column mapping feature. There are four types of
>>> mapping schema (https://phoenix.apache.org/columnencoding.html). Is
>>> there any documentation that shows how to encode/map string column name in
>>> Phoenix to number column qualifier in Hbase?
>>>
>>> We are using Lily Hbase indexer to do the batch indexing. So if the
>>> column qualifier is number. We need find a way to decode it back to the
>>> original String column name.
>>>
>>> Thanks,
>>> Shawn
>>>
>>

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