I usually get events like this when a wrong index is being used. Single block reads are index reads and you're reading a key from index. And repeating the opearation many times. Many, many times. Mladen Gogala Sr. Oracle DBA 1500 Broadway, 6th floor New York, NY 10036 (212) 329-5201 www.vmsinfo.com The Leader in Integrated Media Intelligence Solutions > -----Original Message----- > From: oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l- > bounce@xxxxxxxxxxxxx] On Behalf Of MVR > Sent: Thursday, December 28, 2006 3:14 PM > To: oracle-l > Subject: 10g Performance: its crawling > > Hello, > > After 10g upgrade, one job started performing very bad, real slow. > It > used to complete in an hour and its taking around 4 hours now. I > have > checked wait history from DBA_HIST_ACTIVE_SESS_HISTORY for last > night's run. Here is a top one event, ordered by TIME_WAITED Column. > > ~~~~~~~~~~~~~~~~~~~~~~~~~ > Wait Event: db file sequential read, > Wait Class: User I/O > > p1text : file# , p1: 328 > p2text : block #, p2: 421640 > p3text : blocks , p3: 1 > > TIME_WAITED: 1327817 > ~~~~~~~~~~~~~~~~~~~~~~~~~ > > Apparently it looks like its trying to read a single index block > from > file 328(afaik). But this time_waited column is driving me crazy. I > thought If I assume that this is an I/O issue, it makes sense, but > we > never had these issues in 9206... so this assumption may not be > right. > How can we figure out Segment name with block# ? I know vetarans use > x$ tables to get this. Anyone any ideas please ? > > Thanks > -- > //www.freelists.org/webpage/oracle-l -- //www.freelists.org/webpage/oracle-l