I cannot seem to figure out why LSAN is reporting this, but if it is a
real leak than it's only a few bytes. Better to have the ASAN tests
actually passing IMO.
* Revert "Revert "Refactor: ClusterController driving cluster-recovery state machine""
Major changes includes:
1. Re-revert Sequencer refactor commits listed below (in listed order):
1.a. This reverts commit bb17e194d9c9888e203421290959bd7f2c075d7f.
1.b. This reverts commit d174bb2e06bff01157d16c652073536c54d17f7f.
1.c. This reverts commit 30b05b469c87d9b526b427751c211fb5cf7ff9cd.
2. Update Status.actor to track ClusterController interface to track
recovery status.
3. Introduce a ServerKnob to define "cluster recovery trace event"
prefix; for now keeping it as "Master", however, it should allow
smooth transition to "Cluster" prefix as it seems more appropriate.
diff-1: Address Jingyu's review comments
diff-2: Introduce ClusterRecovery actor to seperate out
cluster recovery code
At present, cluster recovery process consists of following steps:
1. ClusterController clusterWatchDatabase actor recruits
master/sequencer process.
2. Sequencer process implements the cluster recovery state machine,
responsible to recruit all other processes as well restore the
cluster state.
Patch proposes a scheme where the cluster recovery state machine
is implemented and driven by the ClusterController process instead
of the Sequencer process.
Advantages of the scheme could be:
1. Simplified design where ClusterController recruits "sequencer"
process like other worker processes compared to current scheme
where "sequencer" process gets special treatment. In newer scheme
sequencer is responsible for maintaining/providing
"committed version" (as expected).
2. ClusterController is responsible for worker processes recruitment,
the sequencer though orchestrating the recovery state machine, it
need to reachout to the ClusterController for recruiting worker
processes etc.
NOTE:
Patch has moved the recovery state machine code from
'sequencer' -> 'cluster-controller' process, however, necessary
updates were done for both functionality as well as performance
improvement reasons.
Next Steps:
Cluster recovery documentation will be updated in near future.
diff-1: Address Jingyu's review comments
At present, cluster recovery process consists of following steps:
1. ClusterController clusterWatchDatabase actor recruits
master/sequencer process.
2. Sequencer process implements the cluster recovery state machine,
responsible to recruit all other processes as well restore the
cluster state.
Patch proposes a scheme where the cluster recovery state machine
is implemented and driven by the ClusterController process instead
of the Sequencer process.
Advantages of the scheme could be:
1. Simplified design where ClusterController recruits "sequencer"
process like other worker processes compared to current scheme
where "sequencer" process gets special treatment. In newer scheme
sequencer is responsible for maintaining/providing
"committed version" (as expected).
2. ClusterController is responsible for worker processes recruitment,
the sequencer though orchestrating the recovery state machine, it
need to reachout to the ClusterController for recruiting worker
processes etc.
NOTE:
Patch has moved the recovery state machine code from
'sequencer' -> 'cluster-controller' process, however, necessary
updates were done for both functionality as well as performance
improvement reasons.
Next Steps:
Cluster recovery documentation will be updated in near future.
At present, cluster recovery process consists of following steps:
1. ClusterController clusterWatchDatabase actor recruits
master/sequencer process.
2. Sequencer process implements the cluster recovery state machine,
responsible to recruit all other processes as well restore the
cluster state.
Patch proposes a scheme where the cluster recovery state machine
is implemented and driven by the ClusterController process instead
of the Sequencer process.
Advantages of the scheme could be:
1. Simplified design where ClusterController recruits "sequencer"
process like other worker processes compared to current scheme
where "sequencer" process gets special treatment. In newer scheme
sequencer is responsible for maintaining/providing
"committed version" (as expected).
2. ClusterController is responsible for worker processes recruitment,
the sequencer though orchestrating the recovery state machine, it
need to reachout to the ClusterController for recruiting worker
processes etc.
NOTE:
Patch has moved the recovery state machine code from
'sequencer' -> 'cluster-controller' process, however, necessary
updates were done for both functionality as well as performance
improvement reasons.
Next Steps:
Cluster recovery documentation will be updated in near future.
We had been disabling -Wdelete-non-virtual-dtor, because this seems to be done intentionally in the generated code of the actor compiler. I spent some time trying to rewrite it in a way that doesn't literally delete/destroy through a pointer to a base class without a virtual destructor, but I was unable to come up with something that passes correctness. My best guess is that we do this so that we can destroy actor state classes, call callbacks registered on the actor SAV, and then destroy the SAV.
Anyway now we'll detect new usages of deleting through a pointer to a base class without a virtual destructor.
fetch commit_sha from source_code_directory (don't assume we're in the source tree anymore),
allow custom tag (if a parameter is passed in as $1)
update README.md
