Unless the PQExpBuffer is required for the duration of the function,
ensure it's always a variable local to the relevant code block. This
mitigates the risk of accidentally accessing a generically named
PQExpBuffer which hasn't been initialised or was previously terminated.
Previously, repmgrd assumed that during a failover, there would not
already be another primary node. However it's possible a node was
promoted manually. While this is not a desirable situation, it's
conceivable this could happen in the wild, so we should check for
it and react accordingly.
Also sanity-check that the follow target can actually be followed.
Addresses issue raised in GitHub #420.
In some corner cases (e.g. immediately after a switchover) where
the current primary has not yet been determined, the provided connection
might not be writeable. This prevents error messages such as
"cannot execute INSERT in a read-only transaction" generating unnecessary
noise in the logs.
Log the output of PQerrorStatus() in a couple of places where it was missing.
Additionally, always log the output of PQerrorStatus() starting with a blank
line, otherwise the first line looks like it was emitted by repmgr, and
it's harder to scan the error message.
Before:
[2019-03-20 11:24:15] [DETAIL] could not connect to server: Connection refused
Is the server running on host "localhost" (::1) and accepting
TCP/IP connections on port 5501?
could not connect to server: Connection refused
Is the server running on host "localhost" (127.0.0.1) and accepting
TCP/IP connections on port 5501?
After:
[2019-03-20 11:27:21] [DETAIL]
could not connect to server: Connection refused
Is the server running on host "localhost" (::1) and accepting
TCP/IP connections on port 5501?
could not connect to server: Connection refused
Is the server running on host "localhost" (127.0.0.1) and accepting
TCP/IP connections on port 5501?
1. The target additional-maintainer-clean was misspelled as
maintainer-additional-clean.
2. Add add missing clean targets, in particular sysutils.o, config.h,
repmgr_version.h, and Makefile.global. While at it, use a wildcard
for obj files.
3. Don't delete configure.
4. Remove generated file doc/version.sgml from the repo.
5. Have maintainer-clean recurse to the doc directory.
If "failover_validation_command" is set, and the command returns an error,
rerun the election.
There is a pause between reruns to avoid "churn"; the length of this pause
is controlled by the configuration parameter "election_rerun_interval".
