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HBase, mail # user - How to understand the TS of each data version?


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Re: How to understand the TS of each data version?
lars hofhansl 2013-09-27, 17:02
Not sure I follow.
You have a single row with two columns?
In your scenario you'd see that supplier c has 15k iff you query the latest data, which seems to be what you want.
Note that you could also query as of TS 4 (c:20k), TS3 (d:20k), TS2 (d:10k)
-- Lars

________________________________
 From: yonghu <[EMAIL PROTECTED]>
To: [EMAIL PROTECTED]
Sent: Friday, September 27, 2013 7:24 AM
Subject: How to understand the TS of each data version?
 

Hello,

In my understanding, the timestamp of each data version is generated by Put
command. The value of TS is either indicated by user or assigned by HBase
itself. If the TS is generated by HBase, it only records when (the time
point) that data version is generated (Have no meaning to the application).
However, if TS is indicated by user, it may have a specific meaning to
applications. The reason why I want to ask this question is: How can I
correctly understand the meaning of following data? Suppose I have a table
which is used to record the internet speed of different suppliers for
specific users.
For example,

rk       Network:Supplier   Network:speed

Tom   {d:1, c:4}                 {10K:1, 20K:3, 15K:5}

Then I can have following different data information representations:

1. Supplier d have speeds 10K and 20K. Supplier c have 15K.
2. Supplier d have speeds 10K, 20K and 15K. We only insert the supplier c
but has not inserted any speed information.

which one is the right understanding? Anyone knows whether there are any
predefined semantics of TS in HBase?

regards!

Yong