Support -checkmempool=N, which runs checks once every N transactions #6776

1. 
   sipa commented at 9:40 pm on October 7, 2015: member
2. in src/init.cpp: in 55ca7f1ac0 outdated

   836@@ -837,7 +837,10 @@ bool AppInit2(boost::thread_group& threadGroup, CScheduler& scheduler)
   837         InitWarning(_("Warning: Unsupported argument -benchmark ignored, use -debug=bench."));
   838 
   839     // Checkmempool and checkblockindex default to true in regtest mode
   840-    mempool.setSanityCheck(GetBoolArg("-checkmempool", chainparams.DefaultConsistencyChecks()));
   841+    int ratio = std::min<int>(std::max<int>(GetArg("-checkmempool", chainparams.DefaultConsistencyChecks() ? 1 : 0), 0), 1000000);
   

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   dcousens commented at 1:03 am on October 8, 2015:

   I feel like this would be clearer as two (or at least one) if conditionals.
3. 
   dcousens commented at 1:04 am on October 8, 2015: contributor

   What is the behaviour currently? How often does a sanity check run right now?
4. 
   sipa commented at 1:07 am on October 8, 2015: member

   Right now runs for every transaction if -checkmempool is specified, otherwise never.

   So the behaviour for =0 and =1 remains the same, but higher number can be used for lower test frequency.

5. in src/txmempool.cpp: in 55ca7f1ac0 outdated

   552@@ -553,7 +553,10 @@ void CTxMemPool::clear()
   553 
   554 void CTxMemPool::check(const CCoinsViewCache *pcoins) const
   555 {
   556-    if (!fSanityCheck)
   557+    if (nCheckFrequency == 0)
   558+        return;
   559+
   560+    if (insecure_rand() >= nCheckFrequency)
   

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   dcousens commented at 1:44 am on October 8, 2015:

   What is the range of insecure_rand?

   edit:2^32?

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   sipa commented at 5:01 pm on October 20, 2015:

   Yes.
6. 
   dcousens commented at 1:45 am on October 8, 2015: contributor

   utACK
7. in src/txmempool.h: in 55ca7f1ac0 outdated

   337@@ -338,7 +338,7 @@ class CTxMemPool
   338      * check does nothing.
   339      */
   340     void check(const CCoinsViewCache *pcoins) const;
   341-    void setSanityCheck(bool _fSanityCheck) { fSanityCheck = _fSanityCheck; }
   342+    void setSanityCheck(double dFrequency = 1.0) { nCheckFrequency = dFrequency * 4294967296.0; }
   

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   jonasschnelli commented at 7:04 am on October 8, 2015:

   Not sure: but would’t it be more clean to use ULONG_MAX here? Also not sure: if using 4294967296 instead of 4294967295(= ULONG_MAX) wouldn’t this result in autocast to uint64_t?

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   sipa commented at 7:06 am on October 8, 2015:

   Note the .0, making it a double constant rather than an int.

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   sipa commented at 7:07 am on October 8, 2015:

   Also, ULONG_MAX gives the maximum value of an unsigned long. Here we need the number of possible values in a uint32_t. That is by definition 2^32.

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   Diapolo commented at 9:00 am on October 31, 2015:

   IMHO this value should’ve taken a small comment :).
8. 
   jonasschnelli commented at 7:09 am on October 8, 2015: contributor

   Nice. utACK (code review).

   Travis issue is unrelated.

9. laanwj added the label Mempool on Oct 8, 2015
10. 
    sdaftuar commented at 4:56 pm on October 20, 2015: member

    ACK. Looks like travis needs to be bumped?
11. Support -checkmempool=N, which runs checks on average once every N transactions ab1f56072a
12. sipa force-pushed on Oct 20, 2015
13. 
    morcos commented at 5:02 pm on October 20, 2015: member

    utACK
14. sipa merged this on Oct 28, 2015
15. sipa closed this on Oct 28, 2015

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16. sipa referenced this in commit e06c14fb59 on Oct 28, 2015
17. 
    gmaxwell commented at 2:12 am on October 28, 2015: contributor

    This has a bug: -checkmempool=1 never checks due to integer overflow in the nCheckFrequency= dFrequency*4294967296 and nCheckFrequency is uint32_t, so the result ends up 0.
18. zkbot referenced this in commit 6d6b780969 on Feb 20, 2018
19. zkbot referenced this in commit 49274558c6 on Feb 20, 2018
20. furszy referenced this in commit eb00d0f62f on Jun 14, 2020
21. DrahtBot locked this on Sep 8, 2021

Contributors
sipa dcousens jonasschnelli Diapolo sdaftuar morcos gmaxwell

Labels
Mempool