Hello Raj. BBW with a p3=0 are a consecuence of the I/O subsystem not being able to provide enough throughput to the database, as Mladen has said. But there are also many others causes for BBW. Check p3.
Also if the session A is waiting for a buffer in the buffer cache (that's a BBW), the buffer is already in the BC so this session has no need (won't) to do a physical I/O for that block. Another thing I think (I'm sorry to disagree with Mladen on this) is that when DBWR hasn't finished writing a buffer to the disk, and a session wants that buffer in exclusive mode, there's a wait and that wait is computed as a write complete wait and not as BBW. please correct me if I'm wrong. thanks HTH Greetings Diego Cutrone >Folks, > >Say a session issues a read request, and finds >another session already >reading the block into the buffer cache. If this >session waits N ms on a >"buffer busy waits" event, does this N ms of wait get >added to the read >times in v$filestat? Or is the readtim in v$filestat >purely physical I/O? > >Thanks >Raj > > -- Please see the official ORACLE-L FAQ: http://www.orafaq.net -- Author: INET: [EMAIL PROTECTED] Fat City Network Services -- 858-538-5051 http://www.fatcity.com San Diego, California -- Mailing list and web hosting services --------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing). ------------ Internet GRATIS es Yahoo! Conexión 4004-1010 desde Buenos Aires. Usuario: yahoo; contraseña: yahoo Más ciudades: http://conexion.yahoo.com.ar -- Please see the official ORACLE-L FAQ: http://www.orafaq.net -- Author: =?iso-8859-1?q?Diego=20Cutrone?= INET: [EMAIL PROTECTED] Fat City Network Services -- 858-538-5051 http://www.fatcity.com San Diego, California -- Mailing list and web hosting services --------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing).
