Our SAN group was complaining that one of our db's was saturating the SAN network with a ton of read's. We tracked it down the the time when the backup's occur. It's version 11.2.0.3 using RAC. We run level 0 backups twice a week on Wednesday and Saturday morning and the rest of the week we do level 1 incremental backups. I noticed block change tracking was disabled so I enabled it. Next day I checked and it still wasn't using BCT. So then I saw a post that says that BCT needs a level 0 or full backup to run before it can start tracking the changed blocks. So I waited until Monday to check and see if it's working as we ran a level 0 on Saturday. Still not working. I've checked all settings and everything seems ok, any ideas what could cause BCTnot to work?
select file# fno, used_change_tracking BCT,
2 incremental_level INCR, datafile_blocks BLKS,
3 block_size blksz, blocks_read READ,
4 round((blocks_read/datafile_blocks) * 100,2) "%READ",
5 blocks WRTN, round((blocks/datafile_blocks)*100,2) "%WRTN"
6 from v$backup_datafile
7 where completion_time between
8 to_date('24-AUG-15 00:00:00', 'dd-mon-rr hh24:mi:ss') and
9 to_date('24-AUG-15 23:59:00', 'dd-mon-rr hh24:mi:ss')
10 order by file#;
FNO BCT INCR BLKS BLKSZ READ %READ WRTN %WRTN
---------- --- ---------- ---------- ---------- ---------- ---------- ---------- ----------
0 NO 5414 16384 5414 100 5414 100
0 NO 5414 16384 5414 100 5414 100
0 NO 5414 16384 5414 100 5414 100
0 NO 5414 16384 5414 100 5414 100
0 NO 5414 16384 5414 100 5414 100
0 NO 5414 16384 5414 100 5414 100
0 NO 5414 16384 5414 100 5414 100
0 NO 5414 16384 5414 100 5414 100
0 NO 5414 16384 5414 100 5414 100
0 NO 5414 16384 5414 100 5414 100
0 NO 5414 16384 5414 100 5414 100
FNO BCT INCR BLKS BLKSZ READ %READ WRTN %WRTN
---------- --- ---------- ---------- ---------- ---------- ---------- ---------- ----------
0 NO 5414 16384 5414 100 5414 100
0 NO 5414 16384 5414 100 5414 100
0 NO 5414 16384 5414 100 5414 100
1 NO 1 262144 8192 262144 100 59 .02
1 NO 1 262144 8192 262144 100 254 .1
2 NO 1 1723264 8192 1723264 100 24888 1.44
2 NO 1 1728256 8192 1728256 100 13461 .78
3 NO 1 4063232 8192 4063232 100 1574 .04
3 NO 1 4063232 8192 4063232 100 1425 .04
4 NO 1 12800 8192 12800 100 15 .12
4 NO 1 12800 8192 12800 100 13 .1
....
But I can see it's enabled:
>COL STATUS FORMAT A8
COL FILENAME FORMAT A60
SELECT STATUS, FILENAME
FROM V$BLOCK_CHANGE_TRACKING;
SYS:PCD01694>SYS:PCD01694>SYS:PCD01694> 2
STATUS FILENAME
-------- ------------------------------------------------------------
ENABLED +DATA/pcd0169/changetracking/ctf.544.888175053