avoiding race condition between master and worker thread in merge
avoiding race condition between master and worker thread in merge

SRCH2/srch2-ngn,SRCH2/srch2-ngn,SRCH2/srch2-ngn,SRCH2/srch2-ngn,SRCH2/srch2-ngn,SRCH2/srch2-ngn,SRCH2/srch2-ngn