This option forks the process and generates a new session. This
effectively detaches it from the shell. Don't forget to redirect stderr
or use syslog for logging!
We have to remove our own node before we check for a new master if force
is set; else master register would fail on the second time since there
already is a master (ourselves), even if we specify -F
This could leave the database in a locked state (pg_start_backup()).
And since all calls to create_pgdir() handle the return value correctly
we simply replace the exit() by a return false
Make this by waiting for all nodes to finish a step, before starting
a new one. So everyone starts promoting or following in a coordinated
fashion.
Also make a few fixes.
Specially, make this a more coordinated process by making all
nodes waiting for the others before going to the next step.
This is one step further in following Andres Freund advices
but there is still a lot to do in order to complete that,
specially it could be needed to add more fields to repl_nodes
and to the shm area.
When deciding which node will be the new master, we should get the
nodes in a well defined order otherwise two standbys could process
nodes with the same priority in different order and end up with
a two master situation.
Because PQcancel() establish a new synchronous connection to the
database, if it fails it means something wrong has happenned with
master. So instead of just ignore the failure, CancelQuery() now
reports a failure condition so we can detect master's death in
that situation.
This is very important specially when only postmaster crashes but
other children/backend connections are still there. Because the
children connection won't fail and CancelQuery() failure is our
only indication of something wrong happenning.
Currently we just ignore the PQcancel() failure which leads us to
a situation in which we just loop forever
trying to cancel the async query.
Reported by: Martin Euser <martin.euser@nl.abnamro.com>
Problem analyzed and bug spotted by: Andres Freund <andres@2ndquadrant.com>
Patch by: Jaime Casanova <jaime@2ndquadrant.com>
voting procedure.
This is because of a race condition inside CheckPrimaryConnection().
This has independently reported by Alex Railean and Dumitru, and Frank Jördens.
Analyzed and fixed by Cédric Villemain.
The fix have been verified to work by Frank
xlog records from master, so it standby should use pg_last_xlog_receive_location()
to report their positions. This solves a possible situation in which
a standby that is considered as new master when promoted is no longer
the best option.
This is important for autofailover to do the right thing when
standbys detected master death at different times.
While this is a new option, seems important for the autofailover
to work properly so i will consider the lack of it a bug and
will backpatch to 2.0 where autofailover was introduced.
For gripe from Alex Railean, about a standby not finding the new
master because the new master hasn't finish promoting.
two nodes with different prorities are equally good to be promoted
the second one (with a lower priority, considering them
in descending order) will win.
Per report from Brailean Dumitru
get a warning for an uninitialized variable.
Also, define InvalidXLogRecPtr. We don't really need it but using
it make the initialization future proof (considering that in 9.3
XLogRecPtr will change its structure).
We need to add an #include and make it use a different path for the
"true" binary.
Maybe we need to make this changes for all BSD systems but having no
evidence of that i prefer to make this only for systems with __FreeBSD__
