factor out initPartIndex to not have long write lock
factor out initPartIndex to not have long write lock

MG-RAST/AWE,paczian/AWE,wgerlach/AWE,MG-RAST/AWE,paczian/AWE,teharrison/AWE,MG-RAST/AWE,wgerlach/AWE,wgerlach/AWE,paczian/AWE,teharrison/AWE,MG-RAST/AWE,teharrison/AWE,wgerlach/AWE,paczian/AWE,wgerlach/AWE,teharrison/AWE,MG-RAST/AWE,paczian/AWE,wgerlach/AWE,teharrison/AWE,teharrison/AWE,MG-RAST/AWE,paczian/AWE