SMON internals for 10g or 11g?

From: Peter Teoh <>
Date: Wed, 25 Jun 2008 12:30:33 +0800
Message-ID: <>

I found a document on smon internal at:

But it was a little outdated. Just looking at the smon trace file generated:

really amazed me on its internal complexity. Wish there could be some document some where to briefly these at the high level :-).

These smon tracing are also really not necessary for the end-users - how do we disable or turned them off?

For example, question from me:

  1. What are those interesting name=internal SQL... statements?
  2. I saw quite a number of:

ORA-00376: file 1 cannot be read at this time ORA-01110: data file 1:

Is that the norm for SMON processing? The timing seemed to indicate that SMON is retrying to read every one second or so, and finally got through on the fifth try....

c. How do u enumerate all the "LIBRARY OBJECT"? And specifically for this one:

LIBRARY OBJECT: object=2377171c
type=TABL flags=EXS/LOC[0005] pflags=[0000] status=VALD load=0

What are its identity? (ie, object type?)

d. Decipher the following - which pertained to the above object:

        DATA BLOCKS:
        data#     heap  pointer    status pins change whr
        ----- -------- -------- --------- ---- ------ ---
            0 23778100 237717d8 I/P/A/-/-    0 NONE   00
            8 2377193c 237711a0 I/P/A/-/-    0 NONE   00
            9 23771a18        0 I/-/-/-/-    0 NONE   0c

e. What lwt, pwt, ltm, ptm, and ref/ind?

      lwt=0x23774438[0x23774438,0x23774438] ltm=0x23774440[0x23774440,0x23774440]

      pwt=0x2377441c[0x2377441c,0x2377441c] ptm=0x23774424[0x23774424,0x23774424]

      ref=0x23774458[0x23774458,0x23774458] lnd=0x23774464[0x23771e08,0x237787c0]

f. What is FOB?

(FOB) flags=2 fib=0x2571345c incno=0 pending i/o cnt=0

     fno=4 lblksz=4 fsiz=201667104

(FOB) flags=2 fib=0x2571311c incno=0 pending i/o cnt=0
fname=/u01/app/oracle/oradata/BABYDB/datafile/o1_mf_sysaux_45xrzfkp_.dbf fno=3 lblksz=4 fsiz=201667104
(FOB) flags=2 fib=0x25712dcc incno=0 pending i/o cnt=0
fname=/u01/app/oracle/oradata/BABYDB/datafile/o1_mf_undotbs1_45xrzdob_.dbf fno=2 lblksz=4 fsiz=201667104
(FOB) flags=2 fib=0x25712a8c incno=0 pending i/o cnt=0
fname=/u01/app/oracle/oradata/BABYDB/datafile/o1_mf_system_45xrz1n7_.dbf fno=1 lblksz=4 fsiz=201667104
Peter Teoh
Received on Tue Jun 24 2008 - 23:30:33 CDT

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