Generic Delta extractor problem

Hello all,

We are trying to pull data from a custom table (ZABC) that has timestamp as one of the field.

We are using a function module instead of a direct table pull because of the volume of the data that is coming in.

In RSO2 we have selected timestamp as delta field.

After initialization. when we do the delta extraction it pulls all the records from the table. For some reason delta is not being pulled out.

here is the select statement:

SELECT (S_S_IF-T_FIELDS) FROM ZABC

WHERE GL_SIRID IN L_R_GL_SIRID AND

RYEAR IN L_R_RYEAR AND

POPER IN L_R_POPER AND

RBUKRS IN L_R_RBUKRS.

Appreciate your response.