Thanks Melissa. I was wrong, I guess. For this is what I found on Metalink.
1. Because SMON acquires the Space Transaction (ST) enqueue in exclusive mode, other processes requiring the enqueue will be blocked. This is typically manifested by multiple <oerr:ORA-1575> errors. 2. SMON sits in a very tight loop while coalescing, and consumes close to 100% CPU. If the system is CPU-bound, the run queue will increase as other processes try to get onto CPU. Regards Raj "Godlewski, Melissa" <[EMAIL PROTECTED]>@fatcity.com on 01/25/2002 05:20:20 PM Please respond to [EMAIL PROTECTED] Sent by: [EMAIL PROTECTED] To: Multiple recipients of list ORACLE-L <[EMAIL PROTECTED]> cc: Check out meta link note:61997.1 SMON - Temporary Segment Cleanup and Free Space Coalescing. For one explanation. -----Original Message----- Sent: Friday, January 25, 2002 4:50 PM To: Multiple recipients of list ORACLE-L Hey Fellas, I have an application DBA who insists that the pctincrease at the data tablespace should be set to 0 so that SMON does not coalesce the tablespace. He says coalesce will be performed by using a scheduled batch job written for that purpose. He states that having SMON to perform an coalesce of the tablespace could cause an performance degrade??? I have never heard of such a thing, but then I dont wanna argue with him. He's got wrinkles on his face, and grey hair ;-) My argument would be, go back to the drawing board, get your tables sized properly, if you anticipate fragmentation. And SMON does not cause a performance degrade? It wakes up every 5 minutes, does hold ST enqueue locks if a tablespace needs coalescing, but it does not cause a performance degrade? Or does it??? Now, can I have a definitive word on this? Any sites, white papers, to refer to that says so, or to the contrary. I need to convince the higher ups. Raj -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: INET: [EMAIL PROTECTED] Fat City Network Services -- (858) 538-5051 FAX: (858) 538-5051 San Diego, California -- Public Internet access / Mailing Lists -------------------------------------------------------------------- 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). -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: INET: [EMAIL PROTECTED] Fat City Network Services -- (858) 538-5051 FAX: (858) 538-5051 San Diego, California -- Public Internet access / Mailing Lists -------------------------------------------------------------------- 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).
