after the spamassassin had run fine around 2 days, i found that at bayes directory (set to /etc/mail/spamassassin/bayes/), it had a new plain text file bayes_journal created and at spam.log, at even scanned mail, a bayes value like
2006-04-13 03:07:34 [11243] i: result: Y 17 - BAYES_99,DNS_FROM_RFC_POST,HELO_DYNAMIC_IPADDR,LONG WORDS, RCVD_IN_NJABL_DUL, URIBL_JP_SURBL, URIBL_OB_SURBL scantime=1.2, size=1702, mid=<unknown>, bayes=0.999999999840567, autolearn=no also logged to the spam.log which not exist as before. so, i wonder like to ask that the bayes value mean and the using of file bayes_journal. Coz from maillist, i found that some problem will caused by huge size of bayes_journal file. thx all.