Would always return "false", but as the value wasn't used anywhere,
the issue was inconsequential.
However while we're at it, actually check the return value in the
two places it's called, to help diagnose any issues in the unlikely
event they occur.
Per issue reported via GitHub PR #671 from user duzhgg.
In PostgreSQL 12 and later we need to append replication configuration
to "postgresql.auto.conf" to guarantee it will be read last, and hence
override any preceding replication configuration which may be haunting
the configuration files.
We've been assuming that "postgresql.auto.conf" will always be present,
but at least one corner case has been observed where that was not the
case on the node being cloned from. Moreover it's perfectly acceptable
that this file does not exist (it will be recreated the next time
ALTER SYSTEM is executed), so we should be prepared to handle that case.
In passing, improve handling of more unlikely errors which might be
encountered when processing "postgresql.auto.conf".
Apparently "ALTER TABLE" (which we were using to convert the
"repl_events" table) does not mark the table as being part of the
extension. Instead, we need to create the new table and copy the
data, as is done with the other tables.
As it seems redirecting stderr to stdin (2>&1) when executing
system commands results in a SIGPIPE (141) return code, making
it impossible to determine the actual return code, redirect
stderr to a temporary file and collate the output from that.
There are possibly better ways of doing this which could
be revisited at a future date.
When cloning from Barman, and --no-upstream-connection was supplied,
the server version number will not be available at this point in the
code. It will however later be extracted from the Barman metadata,
so move the check for the --waldir pg_basebackup option to after
this point.
Also add an explicit check that a server version number has been
obtained (and fall back to extracting it from the cloned data
directory), as subsequent operations depend on knowing this to
be performed correctly.
From PostgreSQL 13, pg_rewind will automatically handle an unclean
shutdown itself, so as long as --force-rewind was provided, so there
is no need to fail with an error.
Note that pg_rewind handles the unclean shutdown by starting PostgreSQL
in single user mode, which it does before performing any checks as
to whether a rewind is actually necessary.
However pg_rewind doesn't take into account the possible presence
of a standby.signal file, so we remove that and recreate it after
pg_rewind was executed.
If two diverged nodes are on the same timeline, currently there's
no way of establishing the divergence point and pg_rewind
is ineffective.
Clarify the log messages to make this clearer.
When executing "repmgr standby clone" in Barman mode, and --waldir
is set in pg_basebackup options, properly report an error if the
target WAL directory could not be created or is not empty.
By setting --waldir in "pg_basebackup_options", standbys cloned using
pg_basebackup would have their WAL directory set to the specified
location and symlinked from the data directory.
This commit causes repmgr to honour that setting even when cloning
from Barman.
Per proposal in GitHub #662, this patch attempts to synchronise each
repmgrd's primary reconnection attempts to prevent potential race
conditions. This relies on each node's clock being correcly
synchronised.
Currently this change is experimental and is not enabled by default.
It can be enabled by setting the repmgr.conf parameter
"reconnect_loop_sync".
In theory the local connection should not be affected by the node's
promotion. However we're handing over control to an external command
which is usually just "repmgr standby promote", but could potentially
be a user-defined script with unknowable side effects. So it's
better to be safe than sorry.
As of PostgreSQL 13, changes to the fundamental replication
configuration can be applied with a simple SIGHUP, no restart
required.
In case the old behaviour is desired, i.e. a full restart to apply
the configuration changes, the new configuration parameter
"standby_follow_restart" can be set. This parameter has no effect
in PostgreSQL 12 and earlier.
In certain corner cases, it's possible repmgrd may end up monitoring
a standby which was a former primary, but the node record has not
yet been updated.
Previously repmgrd would abort the promotion with a cryptic message
about being unable to find a node record for node_id -1 (the
default value for an unknown node id).
This commit addes a new configuration option "always_promote", which
determines whether repmgrd should promote the node in this case.
The default is "false", to effectively maintain the existing behaviour.
Logging output has also been improved to make it clearer what has
happened when this situation occurs.
If the control file couldn't be parsed for whatever reason, return
the default value for the requested parameter.
It'd be better to have the caller pass in a pointer to the parameter
and have the function return bool so the caller doesn't assume the
control file was read successfully. This is important for handling
DBState, where no "value unknown" default is available.
