System action on table

Hello,

My query is regarding how system read the table data.

For example we created three reports named R55ABC, R55PQR and R55XYZ. The table used by them is as follows.

The Report R55ABC --  F0901, F0911.

The Report R55PQR -- F0911.

The Report R55XYZ -- F0005,F0901, F0902.

Note : These UBE used to take more than 30 min. to give the output since PO value ie From and To value is one year.

My query starts from there.

Query 1 - If the above three reports run in there different JOBQ simultaneously.Then how system will behave i.e course of action.How the three of the report will fetch the data.