AX 2009 - QueryRun.next() taking too long to be completed.

Hello,

Yesterday , i build batch that export data to excel using query with x++(the query is based on TaxTrans and TaxTrans_In  tables).It worked fine i can export 60000 line on 10minute.

Today, i run the export and ax client freeze and take a long time. when i debug the system blo on the ling QueryRun.next() 

I do not why QueryRun.next()  take too long to be completed.

Any regard in this point.

Thank you in advance