Disctribution of rows in Fall back AMPs

Database
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Disctribution of rows in Fall back AMPs

Hi All,

Rows will be distributed among the AMPs based on PI value.

But if i consider that the table is fall back protected and I insert a row in it, then the row will go to appropriate AMP and get stored(say in AMP-0). but since the table is Fall Back protected, copy of primary row will be maintained in Fall back AMP. If i consider that there is 4 AMP cluster then where the Fall back row will be stored i.e. whether in AMP-1, AMP-2 or AMP-3 ?  How the Fall Back Amp will be decided, whether any Hashing mechanism is used in it??

5 REPLIES
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Re: Disctribution of rows in Fall back AMPs

Hi Mahesh,

it's using the same hashing algorithm, but a different hashmap, the Fallback Hashmap.

Check the Database Design manual:

Chapter 8: Teradata Database Indexes and Partitioning

Hash Maps

 

Dieter

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Re: Disctribution of rows in Fall back AMPs

Thank you Dieter. I will refer the manual suggested by you.

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Re: Disctribution of rows in Fall back AMPs

Hi,

I searched this Manual in "http://www.teradatamagazine.com/" after registering to it  but I cannot find such manual to refer. Where actually i can get such Teradata manuals? Please help me out.

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Re: Disctribution of rows in Fall back AMPs

Hi Mahesh,

you'll find all Teradata manuals at http://www.info.teradata.com

Database Design

Or better get the full set:

Teradata 14.10 User Documentation CD-ROM

No need to register ;-)

Dieter

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Re: Disctribution of rows in Fall back AMPs

I got them Dieter. thanks a lot.