Problems with archiving custom data



i am currently developing an own Piwik plugin and have problems with archiving the plug-in data.
On the analyzed web page information of different types may be requested. I save a request in a custom variable for the page:

custom_var_k1: request
custom_var_v1: typeA

custom_var_k1: request
custom_var_v1: typeB

The report itself works and looks as follows:


TypeA 2
TypeB 1

In the Archiver.php i use the queryActionsByDimension with the param $where=‘custom_var_k4 = “request”’ to count the request for each type and save them in the archive:

name 		| value

Request_Type_A | 1
Request_Type_B | 2

How can i get this data in the api-method ? I have tried to save the names (Type_A, Type_B) in a blob and get the values by $archive->getDataTableFromNumeric($names), but this helps me only for a period of one day.
Is there any good tutorial for the archiving process ?

Thank you for your time

(Sorry for my bad english, i am from germany)