Enabling snapshot generation when loading from ledger tool

[roryharr]

Problem

#9496

When creating a snapshot with ledger-tool, snapshot generation is disabled, and the last full snapshot slot isn't set. This allows zero lamport single reference accounts can be removed improperly

Summary of Changes

• Create a snapshot constructor: new_generate_snapshots_externally
• Use the the new snapshot constructor if load_and_process_ledger is called with snapshot_slot populated.
• Assert that latest_full_snapshot_slot is set if building an incremental snapshot in ledger tool

Fixes #9496

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 82.6%. Comparing base (a79a700) to head (3e8a12e).
⚠️ Report is 24 commits behind head on master.

Additional details and impacted files

@@             Coverage Diff             @@
##           master   #10064       +/-   ##
===========================================
+ Coverage    70.9%    82.6%    +11.6%     
===========================================
  Files         711      844      +133     
  Lines      211507   316672   +105165     
===========================================
+ Hits       150014   261611   +111597     
+ Misses      61493    55061     -6432     

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[roryharr]

I'm not sure who should be on the review. Add anyone else if required.

[brooksprumo]

I like this solution.

[brooksprumo]

I think we should backport to v3.1.

We could do v3.0 as well, but not sure if it is needed. The workaround is to only create full snapshots with ledger-tool, and not incremental snapshots.

[brooksprumo]

Nice work!

[mergify]

Backports to the beta branch are to be avoided unless absolutely necessary for fixing bugs, security issues, and perf regressions. Changes intended for backport should be structured such that a minimum effective diff can be committed separately from any refactoring, plumbing, cleanup, etc that are not strictly necessary to achieve the goal. Any of the latter should go only into master and ride the normal stabilization schedule. Exceptions include CI/metrics changes, CLI improvements and documentation updates on a case by case basis.

[roryharr]

Nice work!

Need a review from steve on this one?

[brooksprumo]

Need a review from steve on this one?

Yeah, I think that'd be good. Also for the backport-ness.

[steviez]

I see Brooks already approved so LGTM.

One question - was there something in AccountsDb that changed that "broke" making incrementals with ledger-tool ? Or, has this always been broken with ledger-tool ? Thinking about if/how this could have been avoided

I think we should backport to v3.1.

Agreed - the change is focused/minimal and create-snapshot is "critical tooling" by virtue of being a part of the cluster restart workflow.

We could do v3.0 as well, but not sure if it is needed. The workaround is to only create full snapshots with ledger-tool, and not incremental snapshots.

Yeah, I think we hold on v3.0 for now. We'll get some runtime for this change in v3.1 with a planned testnet halt+restart. Assuming no issues, we'll be looking to take v3.1 to MNB very soon after so we hopefully won't need the v3.0 BP

[t-nelson]

Thinking about if/how this could have been avoided

SnapshotConfig is too convenient. Default impl, SnapshotUsage enum, convenience constructors. Config structs should force review of call sites whenever changed