Add CChain object for headers-only chain #10894

1. 
   jonasschnelli commented at 1:57 pm on July 21, 2017: contributor

   This PR introduces a CChain object for the headers chain. It allows to better inspect the headers chain (things like reorg detection). It would simplify a lot of things for a possible light client (SPV) mode.

   Slightly improves the headers-chain fork reporting in getchaintips.

2. Add CChain object for headers-only chain 890c935d18
3. jonasschnelli added the label Block storage on Jul 21, 2017
4. jonasschnelli added this to the "In progress" column in a project

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5. in src/validation.cpp:2617 in 890c935d18

   2613@@ -2613,7 +2614,10 @@ static CBlockIndex* AddToBlockIndex(const CBlockHeader& block)
   2614     pindexNew->nChainWork = (pindexNew->pprev ? pindexNew->pprev->nChainWork : 0) + GetBlockProof(*pindexNew);
   2615     pindexNew->RaiseValidity(BLOCK_VALID_TREE);
   2616     if (pindexBestHeader == NULL || pindexBestHeader->nChainWork < pindexNew->nChainWork)
   2617+    {
   

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   meshcollider commented at 7:52 pm on July 21, 2017:

   Nit, brace on new line
6. in src/validation.cpp:3490 in 890c935d18

   3486@@ -3483,7 +3487,10 @@ bool static LoadBlockIndexDB(const CChainParams& chainparams)
   3487         if (pindex->pprev)
   3488             pindex->BuildSkip();
   3489         if (pindex->IsValid(BLOCK_VALID_TREE) && (pindexBestHeader == NULL || CBlockIndexWorkComparator()(pindexBestHeader, pindex)))
   3490+        {
   

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   meshcollider commented at 7:52 pm on July 21, 2017:

   Same here
7. 
   meshcollider commented at 7:53 pm on July 21, 2017: contributor

   utACK https://github.com/bitcoin/bitcoin/commit/890c935d187401dc9e95f2a2c992a5aec4f438ad Couple of nits
8. 
   sipa commented at 8:00 pm on July 21, 2017: member

   It is unnecessary to add a new CChain object (3.5 MiB of RAM) for this. You can test whether pindex is an ancestor of pindexBestHeader using ‘pindexBestHeader->GetAncestor(pindex->nHeight) == pindex`.
9. 
   jonasschnelli commented at 7:16 am on July 24, 2017: contributor

   @sipa: For the light client headers based fork detection the FindFork() method would be very handy. Maybe have a look at the “sketch” SPV code for the wallet: https://github.com/bitcoin/bitcoin/pull/9483/files#diff-b2bb174788c7409b671c46ccc86034bdR1182
10. 
    jonasschnelli commented at 7:17 am on July 24, 2017: contributor

    If one runs in full non validation mode (light client mode), the memory consumption would be ~the same, because only the headers chain will require memory (the chainActive will be empty).
11. 
    sipa commented at 7:47 am on July 24, 2017: member

    @jonasschnelli You can use FindCommonAncestor between two CBlockIndex objects if you don’t have a CChain, instead of FindFork.
12. 
    jonasschnelli commented at 8:41 am on July 24, 2017: contributor

    Thanks @sipa. Makes sense. Closing for now.
13. jonasschnelli closed this on Jul 24, 2017

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14. 
    danra commented at 3:25 pm on September 30, 2017: contributor

    @jonasschnelli @sipa If this is no longer relevant I suggest removing it from the “Client-Mode (SPV)” project to reduce noise (especially since there are already two other, somewhat overlapping, PRs in the project)
15. jonasschnelli removed this from the "In progress" column in a project

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16. DrahtBot locked this on Sep 8, 2021

Contributors
jonasschnelli meshcollider sipa danra

Labels
Block storage