validation: do not wipe utxo cache for stats/scans/snapshots #33680

1. 
   l0rinc commented at 2:46 pm on October 22, 2025: contributor

   Revival of #30610 (comment) with the remaining comments applied on top

   Since #28280, the cost of a non-wiping sync of the UTXO cache is only proportional to the number of dirty entries, rather than proportional to the size of the entire cache. Because of that, there is no reason to perform a wiping flush in case the contents of the cache is still useful.

   Split the FlushStateMode::ALWAYS mode into a FORCE_SYNC (non-wiping) and a FORCE_FLUSH (wiping), and then use the former in scantxoutset, gettxoutsetinfo, and in the currently-unused CreateUTXOSnapshot.

2. DrahtBot added the label Validation on Oct 22, 2025
3. 
   DrahtBot commented at 2:46 pm on October 22, 2025: contributor

   The following sections might be updated with supplementary metadata relevant to reviewers and maintainers.

   Code Coverage & Benchmarks

   For details see: https://corecheck.dev/bitcoin/bitcoin/pulls/33680.

   Reviews

   See the guideline for information on the review process. A summary of reviews will appear here.

   Conflicts

   Reviewers, this pull request conflicts with the following ones:

   • #33669 (Add libbitcoinkernel example files by w0xlt)
   • #33602 ([IBD] coins: reduce lookups in dbcache layer propagation by l0rinc)
   • #31382 (kernel: Flush in ChainstateManager destructor by TheCharlatan)
   • #30595 (kernel: Introduce C header API by TheCharlatan)
   • #30342 (kernel, logging: Pass Logger instances to kernel objects by ryanofsky)
   • #29700 (kernel, refactor: return error status on all fatal errors by ryanofsky)
   • #29641 (scripted-diff: Use LogInfo over LogPrintf [WIP, NOMERGE, DRAFT] by maflcko)

   If you consider this pull request important, please also help to review the conflicting pull requests. Ideally, start with the one that should be merged first.

4. l0rinc force-pushed on Oct 22, 2025
5. l0rinc force-pushed on Oct 22, 2025
6. validation: do not wipe utxo cache for stats/scans/snapshots

   Co-authored-by: l0rinc <pap.lorinc@gmail.com>

   b92ee75510
7. l0rinc force-pushed on Oct 22, 2025

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