HeadersSync tracking issue #33547

1. 
   hodlinator commented at 9:37 am on October 6, 2025: contributor

   End Goal: Make the headers sync phase quicker and less prone to fail, while improving implementation and test code.

   The Bitcoin Optech Podcast episode for Newsletter 322 (https://bitcoinops.org/en/podcast/2024/10/01/) among other things prompted the (re)discovery of the possible improvement of caching headers so they only needed to be downloaded once. To avoid adding unnecessary resource demands on nodes, the number of HeaderSyncState instances created over time should ideally be made more predictable first (see old comments at #25720 (review) & #25720 (comment)).

   Issues

   Not required, but getting these in first helps make later changes clearer:

   • #32740
   • #32579

   Critical path (not yet ready for general review):

   • Heavily WIP: More predictable HeaderSyncState creation - https://github.com/hodlinator/bitcoin/tree/2025/08/headerssync_predictability
   • WIP: https://github.com/l0rinc/bitcoin/pull/3

   Adjacent:

   • #33553 (ameliorates intermittent issue #26391)
2. 
   mzumsande commented at 9:50 pm on October 6, 2025: contributor

   I opened #33553 to address the problem from #26391 .
3. glozow added the label Tracking Issue on Oct 9, 2025

Contributors
hodlinator mzumsande

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Tracking Issue