Working on Oracle GoldenGate can be an interesting adventure. In such a case, I have been doing some migration work for a client. Half way though the migration, the target system ran out of resources need to create the tablespaces and store files export and trail files (i.e. disk space and a story for another time). The impact to the migration was that everything had to stop until resources were allocated.
Part of the allocation of resources was to change the mount point name. If you know anything about Oracle GoldenGate Replicats, using a static mount point is not the best approach (slipped my mind at the time); however, I made this mistake. When the mount point name changed, all the replicats broke because they couldn’t locate the trail files where specified.
When I initially setup the replicat I used a static mount point. Let’s take a look at the create replicat statement I used initially:
--Add Replicat Process ADD REPLICAT REPM01, EXTTRAIL /orabackup/ggate/trail/ars/ra, DESC "Replicat process for a schema” START REPLICAT REPM01, ATCSN
As you can see the replicat is looking for the “ra” trail files on the “/orabackup” mount point.
During the allocation of space the mount point “/orabackup” was changed to “/orabkup”. How does this affect the replicat? Simple, the replicat will through an OGG-01091 error stating that it coudn’t find the trail file.
ERROR OGG-01091 Unable to open file “/orabackup/ggate/trail/ars/ra000000” (error 2, No such file or directory).
The solution to fixing this problem is to capture the last CSN number from the Checkpoint table.
SQL> select group_name, rba, seqno, log_cmplt_csn from checkpoint where group_name = 'REPM01'; GROUP_NA RBA SEQNO LOG_CMPLT_CSN -------- ---------- ---------- ----------------------------------- REPM01 544013 1 11108080706671
Once the last completed CSN has been identified, then the replicat can be dropped, recreated with the new path to the trail file.
GGSCI> dblogin userid ggate password GGSCI> delete replicat REPM01 GGSCI> add replicat REPM01, EXTTRAIL /orabkup/ggate/trail/ars/ra, DESC "Replicat process for a schema” GGSCI> start replicat REPM01, atcsn 11108080706671 GGSCI> info all Program Status Group Lag at Chkpt Time Since Chkpt MANAGER RUNNING REPLICAT RUNNING REPM01 00:00:00 00:00:06
When setting up locations for your trail files make sure they are not static locations. Realitve locations should be used. In most Oracle GoldenGate architectures the “dirdat” directory under $OGG_HOME is used for trails files; however, if you need more space for trail files the “dirdat” directory can be linked to a directory on a larger mount point. This will keep the replicat consistant for trail file purposes and make it easier to manage the names of the mount point if the static name changes.