How to find out amount of undo generated in 10g and 9i? for a given session

Question

Hi All,
I am on v10.2 on Linux. How can I find out amount of undo generated in my session ?
I tried this
SQL> select a.STATISTIC#, a.VALUE, b.NAME from v$mystat a , v$statname b
2 where a.statistic# = b.statistic# and (b.name like '%undo%' or b.name like '%rollback%') ;
STATISTIC# VALUE NAME
5 0 user rollbacks
75 0 DBWR undo block writes
176 132 undo change vector size
177 0 transaction tables consistent reads - undo records applied
178 0 transaction tables consistent read rollbacks
179 0 data blocks consistent reads - undo records applied
182 0 rollbacks only - consistent read gets
183 0 cleanouts and rollbacks - consistent read gets
188 0 rollback changes - undo records applied
189 0 transaction rollbacks
200 0 auto extends on undo tablespace
202 0 total number of undo segments dropped
220 0 global undo segment hints helped
221 0 global undo segment hints were stale
222 0 local undo segment hints helped
223 0 local undo segment hints were stale
224 0 undo segment header was pinned
226 0 SMON posted for undo segment recovery
229 0 SMON posted for undo segment shrink
236 0 IMU undo retention flush
241 0 IMU CR rollbacks
242 488 IMU undo allocation size
22 rows selected.
SQL>
SQL> create table temp1 as select * from dba_objects where 1=2 ;
Table created.
SQL> select a.STATISTIC#, a.VALUE, b.NAME from v$mystat a , v$statname b
2 where a.statistic# = b.statistic# and (b.name like '%undo%' or b.name like '%rollback%') ;
STATISTIC# VALUE NAME
5 0 user rollbacks
75 0 DBWR undo block writes
176 30280 undo change vector size
177 0 transaction tables consistent reads - undo records applied
178 0 transaction tables consistent read rollbacks
179 8 data blocks consistent reads - undo records applied
182 8 rollbacks only - consistent read gets
183 0 cleanouts and rollbacks - consistent read gets
188 0 rollback changes - undo records applied
189 0 transaction rollbacks
200 0 auto extends on undo tablespace
202 0 total number of undo segments dropped
220 0 global undo segment hints helped
221 0 global undo segment hints were stale
222 0 local undo segment hints helped
223 0 local undo segment hints were stale
224 0 undo segment header was pinned
226 0 SMON posted for undo segment recovery
229 0 SMON posted for undo segment shrink
236 0 IMU undo retention flush
241 0 IMU CR rollbacks
242 560 IMU undo allocation size
22 rows selected.
SQL> insert /*+ APPEND */ into temp1 select * from dba_objects ;
91057 rows created.
SQL> commit ;
Commit complete.
SQL> select a.STATISTIC#, a.VALUE, b.NAME from v$mystat a , v$statname b
2 where a.statistic# = b.statistic# and (b.name like '%undo%' or b.name like '%rollback%') ;
STATISTIC# VALUE NAME
5 0 user rollbacks
75 0 DBWR undo block writes
176 171356 undo change vector size
177 0 transaction tables consistent reads - undo records applied
178 0 transaction tables consistent read rollbacks
179 166 data blocks consistent reads - undo records applied
182 91 rollbacks only - consistent read gets
183 0 cleanouts and rollbacks - consistent read gets
188 0 rollback changes - undo records applied
189 10 transaction rollbacks
200 0 auto extends on undo tablespace
202 0 total number of undo segments dropped
220 0 global undo segment hints helped
221 0 global undo segment hints were stale
222 0 local undo segment hints helped
223 0 local undo segment hints were stale
224 0 undo segment header was pinned
226 0 SMON posted for undo segment recovery
229 0 SMON posted for undo segment shrink
236 0 IMU undo retention flush
241 0 IMU CR rollbacks
242 1352 IMU undo allocation size
22 rows selected.
What exactly is "undo change vector size" ?
Also, if I am on v 9.2, this ( undo change vector size ) stat name is not there. What can be used in v9.2 ?
Thanks in advance.

Answer 1

Hi..
>
SET LINESIZE 200
COLUMN username FORMAT A15
SELECT s.username,
s.sid,
s.serial#,
t.used_ublk,
t.used_urec,
rs.segment_name,
r.rssize,
r.status
FROM v$transaction t,
v$session s,
v$rollstat r,
dba_rollback_segs rs
WHERE s.saddr = t.ses_addr
AND t.xidusn = r.usn
AND rs.segment_id = t.xidusn
ORDER BY t.used_ublk DESC;
>
HTH
Anand