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

pull sipa wants to merge 1 commits into bitcoin:master from sipa:fraccheck changing 3 files +12 −6

sipa commented at 9:40 PM on October 7, 2015: member

No description provided.

in src/init.cpp:None in 55ca7f1ac0 outdated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);

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.

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?
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.

in src/txmempool.cpp:None in 55ca7f1ac0 outdated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)

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

What is the range of insecure_rand?

edit:2^32?

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

Yes.

dcousens commented at 1:45 AM on October 8, 2015: contributor

utACK
in src/txmempool.h:None in 55ca7f1ac0 outdated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; }
```
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?

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

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

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.

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

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

Nice. utACK (code review).

Travis issue is unrelated.
laanwj added the label Mempool on Oct 8, 2015
sdaftuar commented at 4:56 PM on October 20, 2015: member

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

utACK
sipa merged this on Oct 28, 2015
sipa closed this on Oct 28, 2015
sipa referenced this in commit e06c14fb59 on Oct 28, 2015
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.
zkbot referenced this in commit 6d6b780969 on Feb 20, 2018
zkbot referenced this in commit 49274558c6 on Feb 20, 2018
furszy referenced this in commit eb00d0f62f on Jun 14, 2020
DrahtBot locked this on Sep 8, 2021

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#6896 Make -checkmempool=1 not fail through int32 overflow