Block Change Tracking File Invalid (RMAN-08606)

Dears,

Today while I was performing a FULL db backup of my production database to disk, I received a weird RMAN-08606 error.

RMAN-08606: WARNING: The Change Tracking File Is Invalid

On reading oracle note, I learnt it is risk to our incremental level 1s. Since the change tracker is missing changed block information.

Oracle says to ignore any backup taken since last incremental level 0, if you have this error. Since those backups potentially are incomplete due to missing changed block info.

So oracle proposes few options like

1. placing this bct file on a relatively less hot filesystem
2. increasing large_pool_size
3. increasing _bct_public_dba_buffer_size to a larger value (use x$krcstat view for getting this value).

This should reduce the wait events related to bct and avoid the situation highlighted.

What I did is as a first measure disabled the bct, since a risk to backup is huge for me. My DB is small around 2TB. So I am not bothered reading 2TB in place of 200GB.

Thanks