Provide the master connection if available, and if not enable
create_event_record() to skip trying to write to the database,
but execute the notification program if defined.
Command to be executed each time an event is logged.
Following formatting sequences will be interpolated:
%e - event type
%d - description
%s - success (1 or 0)
%t - timestamp
No need to prefix each line with the program name; this was pretty
inconsistent anyway. The only place where log output needs to identify
the outputting program is when syslog is being used, which is done
anyway.
This makes keeping track of events such as failovers
much easier. Note that this is for convenience and is
not a foolproof auditing log.
Sample output:
repmgr_db=# SELECT * from repmgr_test.repl_events ;
node_id | event | successful | event_timestamp | details
---------+--------------------------+------------+-------------------------------+----------------------------------------------------------
1 | master_register | t | 2015-03-06 14:14:08.196636+09 |
2 | standby_clone | t | 2015-03-06 14:14:17.660768+09 | Backup method: pg_basebackup; --force: N
2 | standby_register | t | 2015-03-06 14:14:18.762222+09 |
4 | witness_create | t | 2015-03-06 14:14:22.072815+09 |
3 | standby_clone | t | 2015-03-06 14:14:23.524673+09 | Backup method: pg_basebackup; --force: N
3 | standby_register | t | 2015-03-06 14:14:24.620161+09 |
2 | repmgrd_start | t | 2015-03-06 14:14:29.639096+09 |
3 | repmgrd_start | t | 2015-03-06 14:14:29.641489+09 |
4 | repmgrd_start | t | 2015-03-06 14:14:29.648002+09 |
2 | standby_promote | t | 2015-03-06 14:15:01.956737+09 | Node 2 was successfully be promoted to master
2 | repmgrd_failover_promote | t | 2015-03-06 14:15:01.964771+09 | Node 2 promoted to master; old master 1 marked as failed
3 | repmgrd_failover_follow | t | 2015-03-06 14:15:07.228493+09 | Node 3 now following new upstream node 2
(12 rows)
This involves mainly abstracting the functions which copy
and create records from repmgr.c to dbutils.c, as they need
to be shared between repmgr and repmgrd.
Per issue noted here:
https://groups.google.com/forum/#!topic/repmgr/v5nu1Xwf6X0
Sometimes it's desirable to re-sync a "stale" data directory
on a standby, rather than start from scratch with pg_basebackup().
This re-adds the rsync code from the 2.x series, with some
modifications.
TODO: tablespace support.
Attempt to attach to the next available upstream node, otherwise
quit monitoring. We'll need to add further options for failover
scenarios, including attempting to attach to another node,
shutting down the server completely etc.
To handle cascaded replication we're going to have to keep track
of each node's upstream node. Also enumerate the node type
("primary", "standby" or "witness") and mark if active.
Use the reported `server_version_num` integer for version number
detection and comparison. This makes it easier to set an arbitrary
minimum supported version (rather than "9.0 or later") as well
as future-proofing for 10.x and later.
wait_connection_availability() did take at least 2 seconds per call in
the old incarnation. Now we may finish a call without any sleep at all
when the result is already ready at the time called
