Disctribution of rows in Fall back AMPs

Database
Enthusiast

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
Senior Apprentice

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

Enthusiast

Re: Disctribution of rows in Fall back AMPs

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

Enthusiast

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.

Senior Apprentice

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

Enthusiast

Re: Disctribution of rows in Fall back AMPs

I got them Dieter. thanks a lot.