We have been struggling to get pr_rewind to work. In desperation we have been
trying to make the use case as simple as possible:)
We have two databases servers running Postgres 10 on two different machine in
the normal Primary/Standby configuration.
Both machines write their WAL archive logs to the same shared drive (called
/ice_dev/wal_archive).
The configuration has the following terms
archive_mode = always
archive_command = 'test ! -f /ice-dev/wal_archive/%f && cp %p
/ice-dev/wal_archive/%f'
full_page_writes = on
wal_log_hints = on
Checksums are enabled
Our procedure that runs on machine A and B is as follows:
1. Build new databases on A and B, and configure A as Primary and B as
Standby databases.
2. Make some changes to the A (the primary) and check that they are
replicated to the B (the standby)
3. Promote B to be the new primary
4. Switch of the A (the original primary)
5. Add the replication slot to B (the new primary) for A (soon to be standby)
6. Add a recovery.conf to A (soon to be standby). File contains
recovery_target_timeline = 'latest' and restore_command = 'cp
/ice-dev/wal_archive/%f "%p"
7. Run pg_rewind on A - this appears to work as it returns the message
'source and target cluster are on the same timeline no rewind required';
8. Start up server A (now a slave)
At this point A is in a read only mode but not replicating. Its logs contain
the following repeating message
2018-08-01 20:30:58 UTC [7257]: [1] user=,db=,app=,client= FATAL: could not
start WAL streaming: ERROR: requested starting point 0/6000000 on timeline 1
is not in this server's history
DETAIL: This server's history forked from timeline 1 at 0/57639D0.
cp: cannot stat '/ice-dev/wal_archive/00000002.history': No such file or
directory
cp: cannot stat '/ice-dev/wal_archive/00000003.history': No such file or
directory
cp: cannot stat '/ice-dev/wal_archive/00000002.history': No such file or
directory
2018-08-01 20:30:58 UTC [6840]: [48] user=,db=,app=,client= LOG: new timeline
2 forked off current database system timeline 1 before current recovery point
0/6000098
cp: cannot stat '/ice-dev/wal_archive/000000010000000000000006': No such file
or directory
We can see the 00000002.history file in B's wal directory.....but it never
appears in the wal_archive directory - not even if we issue a checkout or even
restart the server.
00000003.history does not appear to exist on either of the machines.
Any ideas what we are doing wrong?
Thanks. Richard
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