More issues: the pg_basebackup -x stream on the cascading replica won't
complete until the xlog rotates on the master. (again, this is
Tuesday's snapshot).
Servers:
.226 == master-master, the writeable master
.227 == master-replica, a direct replica of master-master
.228 == replica-replica, a cascading replica of master-replica
1. recreated master-master, loaded it with some dummy databases.
2. created master-replica
3. took pg_basebackup -x stream of master-master on master-replica
4. edited recovery.conf and started master-replica. started normally.
5. created a table on master-master. change replicated to master-replica.
6. created replica-replica. started a pg_basebackup -x stream from
master-replica
7. pg_basebackup hung forever. output of -v:
xlog start point: 0/A000020
pg_basebackup: starting background WAL receiver
xlog end point: 0/A01C188
pg_basebackup: waiting for background process to finish streaming...
8. tried creating a table on master-master to create a write. this had
no effect (although the table did replicate to master-replica).
Here's pg_stat_replication on master-master while the basebackup is hung:
1385 | 16393 | replicator | walreceiver | ###.###.61.227 | | 45396 | 2012-
05-13 19:05:11.972471+00 | streaming | 0/A024F50 | 0/A024F50 |
0/A024F50 | 0/A024F50
| 0 | async
Here's pg_stat_replication on master-replica while basebackup is hung:
1243 | 16393 | replicator | pg_basebackup | ###.###.61.228 | | 49218 | 2012-
05-13 19:06:07.606378+00 | startup | 0/0 | | |
| 0 | async1244 | 16393 | replicator | pg_basebackup | ###.###.61.228 | | 49219 |
2012-
05-13 19:06:07.611996+00 | streaming | 0/A024F50 | | |
| 0 | async
9. Ran pg_xlog_switch() on the master.
10. basebackup completed on replica-replica.
11. edited recovery.conf on replica-replica and started it. works fine.
12. created a new table on master-master, changed replicated to
replica-replica.
--
Josh Berkus
PostgreSQL Experts Inc.
http://pgexperts.com