storage: release quota on failed Raft proposals

[nvanbenschoten]

Fixes #34180.
Fixes #35493.
Fixes #36983.
Fixes #37108.
Fixes #37371.
Fixes #37384.
Fixes #37551.
Fixes #37879.
Fixes #38095.
Fixes #38131.
Fixes #38136.
Fixes #38549.
Fixes #38552.
Fixes #38555.
Fixes #38560.
Fixes #38562.
Fixes #38563.
Fixes #38569.
Fixes #38578.
Fixes #38600.

A lot of the early issues fixed by this had previous failures, but nothing very recent or actionable. I think it's worth closing them now that they should be fixed in the short term.

This fixes a bug introduced in 1ff3556 where Raft proposal quota is no longer released when Replica.propose fails. This used to happen here, but that code was accidentally lost in the rewrite.

I tracked this down by running a series of import/tpch/nodes=4 and scrub/all-checks/tpcc/w=100 roachtests. About half the time, the import would stall after a few hours and the roachtest health reports would start logging lines like: n1/s1 2.00 metrics requests.slow.latch. I tracked the stalled latch acquisition to a stalled proposal quota acquisition by a conflicting command. The range debug page showed the following:

We see that the Leaseholder of the Range has no pending commands but also no available proposal quota. This indicates a proposal quota leak, which led to me finding the lost release in this error case.

The (now confirmed) theory for what went wrong in these roachtests is that they are performing imports, which generate a large number of AddSSTRequests. These requests are typically larger than the available proposal quota for a range, meaning that they request all of its available quota. The effect of this is that if even a single byte of quota is leaked, the entire range will seize up and stall when an AddSSTRequests is issued. Instrumentation revealed that a ChangeReplicas request with a quota size equal to the leaked amount was failing due to the error:

received invalid ChangeReplicasTrigger REMOVE_REPLICA((n3,s3):3): updated=[(n1,s1):1 (n4,s4):2 (n2,s2):4] next=5 to remove self (leaseholder)

Because of the missing error handling, this quota was not being released back into the pool, causing future requests to get stuck indefinitely waiting for leaked quota, stalling the entire import.

[cockroach-teamcity]

This change is 

[tbg]

thanks for tracking this down, my only substantial comment is about where to defer cleanupFailedProposal. Looking forward to a flurry of close notifications in my inbox.

A for of the early issues

Something's off there.

Reviewed 2 of 2 files at r1, 1 of 1 files at r2, 1 of 1 files at r3, 3 of 3 files at r4, 4 of 4 files at r5.
Reviewable status: complete! 1 of 0 LGTMs obtained (waiting on @nvanbenschoten)

---

pkg/storage/replica_proposal_buf.go, line 417 at r4 (raw file):

proposals,

---

pkg/storage/replica_raft.go, line 239 at r5 (raw file):

This ensures

---

pkg/storage/replica_raft.go, line 241 at r5 (raw file):

	// proposal buffer successfully. This ensure that we always release any
	// quota that we acquire.
	defer func() {

Is this in the right place? I'd have thought this would pair more naturally somewhere around

cockroach/pkg/storage/replica_raft.go

Lines 190 to 192 in f39dd66

	if err := r.maybeAcquireProposalQuota(ctx, proposal.quotaSize); err != nil {
	return nil, nil, 0, roachpb.NewError(err)
	}

i.e. just after acquiring the quota. As written, we have to worry about any early returns between acquiring the quota and calling into propose. For example, and this doesn't matter in production but demonstrates the point, a TestingProposalFilter right now will leak any acquired quota:

cockroach/pkg/storage/replica_raft.go

Lines 201 to 206 in f39dd66

	if pErr := filter(filterArgs); pErr != nil {
	return nil, nil, 0, pErr
	}
	}
	maxLeaseIndex, pErr := r.propose(ctx, proposal)

[nvanbenschoten]

Something's off there.

Done.

bors r=tbg

Reviewable status: complete! 0 of 0 LGTMs obtained (and 1 stale) (waiting on @tbg)

---

pkg/storage/replica_proposal_buf.go, line 417 at r4 (raw file):

Previously, tbg (Tobias Grieger) wrote…

proposals,

Done.

---

pkg/storage/replica_raft.go, line 239 at r5 (raw file):

Previously, tbg (Tobias Grieger) wrote…

This ensures

Done.

---

pkg/storage/replica_raft.go, line 241 at r5 (raw file):

Previously, tbg (Tobias Grieger) wrote…

Is this in the right place? I'd have thought this would pair more naturally somewhere around

cockroach/pkg/storage/replica_raft.go

Lines 190 to 192 in f39dd66

	if err := r.maybeAcquireProposalQuota(ctx, proposal.quotaSize); err != nil {
	return nil, nil, 0, roachpb.NewError(err)
	}

i.e. just after acquiring the quota. As written, we have to worry about any early returns between acquiring the quota and calling into propose. For example, and this doesn't matter in production but demonstrates the point, a TestingProposalFilter right now will leak any acquired quota:

cockroach/pkg/storage/replica_raft.go

Lines 201 to 206 in f39dd66

	if pErr := filter(filterArgs); pErr != nil {
	return nil, nil, 0, pErr
	}
	}
	maxLeaseIndex, pErr := r.propose(ctx, proposal)

Done.

[craig]

Build succeeded

• GitHub CI (Cockroach)