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From "Chao Fang" <cfang1...@aliyun.com>
Subject How carbon data create startkey and endkey for a filter query
Date Fri, 18 May 2018 16:02:02 GMT
Hello,

 

Firstly I describe what I learn about the process of a query as follow:

 

When there comes a sql with filter like “select * from A where A.a in
(“a”,”b”,”c)” , there exists three steps to do,

Step1, Carbon index file could locate the corresponding Carbon data file
that satisfy our query, 

and I believe that Carbon index could quickly locate the data by using
startkey and endky.

Step2, footer of those Carbon data files could locate the corresponding
Blocket that satisfy our query

Step3, Blocket could locate the corresponding row in it that satisfy our
query as this column is sorted.

 

So now I have a question for step1, how could carbon create the startkey and
endkey just using the provided filter condition like A.a in (“a“,”b”,
“c”)?

 

Great thanks,

Chao


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