This is used for determining a timeout when reconnecting to the standby
after executing the "follow_command". This will normally not need to be
set explicitly, but maybe useful in cases where the standby's startup
phase can last longer than usual.
- emit explicit startup NOTICE
- emit NOTICE when falling back to degraded monitoring on a primary node
- improve log message and event notification details when monitoring
a former primary which has been reconnected as a standby
If repmgrd is running in degraded mode on a primary which has been stopped,
then manually been brought back online as a standby (e.g. by creating
recovery.conf and starting the server), ensure it not only detects the
change but automatically updates the node record so it can resume
monitoring the node as a standby.
Previously, repmgrd was looping waiting for the record to be updated
(as is done transparently when executing "repmgr node rejoin") but
if the record was not updated within the timeout period (e.g. by
"repmgr standby register) it would fail to resume monitoring as a
standby.
It seems reasonable to have repmgrd automatically update the node record,
as this will restore failover capability as quickly as possible. If this
is not desired, then the onus is on the user to shut down repmgrd while
making the desired changes.
This was required for a specific use case during pre-release
development and is no longer needed now the physical streaming
replication handling is implemented.
The warning emitted gives the impression that monitoring data shouldn't
be written if there's no streaming replication, but we can and should
do this as long as we have a primary connection.
Explictly document this in the code.
Also remove an unused variable warning.
If repmgrd is monitoring a primary which is taken off-line, then later
restored as a standby, detect this change and resume monitoring
in standby node.
Addresses GitHub #338.
All disconnected nodes will be in a static, known state, so as long as
each node has the same meta-information (repmgr.nodes) and is able
to retrieve the last receive LSN of the other nodes, it is possible
for each node to independently determine the best promotion candidate,
thereby reaching consensus without an explicit "voting" process.
get_new_primary() returns NULL if no notification for the new primary has
been received, but the code was expecting it to return UNKNOWN_NODE_ID,
which was causing repmgrd to prematurely drop out of the new primary
detection loop if no notification had been received by the time the loop
started.
Also store the electoral term as a single row, single column table,
to ensure that all repmgrds see the same turn. It is then bumped
by the winning node after it gets promoted.
Various logging improvements.
In previous versions of repmgr, some options had ambiguous meanings,
and/or were used for slightly different purposes. This way we end
up with a couple more options (most of which probably won't need
adjusting) but greater clarity and flexibility.
Removed:
master_reponse_timeout:
renamed to "async_query_timeout", as this was its main usage
retry_promote_interval_secs:
replaced by "primary_notification_timeout"
Added:
async_query_timeout:
timeout (in seconds) when executing asynchronous queries
primary_notification_timeout:
number of seconds to wait for notification from the new primary
after a failover
primary_follow_timeout:
number of seconds to wait for the new primary to become available
when executing "repmgr standby follow"
