Fix Parallel verification issues (v1) #1417

shargon · 2020-01-15T14:04:02Z

Note: The issue doesn't happen without parallel verification.

src/neo/Ledger/SendersFeeMonitor.cs

shargon · 2020-01-15T14:15:39Z

I will fix the UT when we decide if this is the right fix. Maybe we should move this check to Blockchain.OnParallelVerified

Tommo-L · 2020-01-16T01:39:03Z

src/neo/Ledger/MemoryPool.cs

+                {
+                    _unsortedTransactions.Remove(hash);
+                    return false;
+                }


I think this isn't the best way. And it's not enough when balance < SendersFeeMonitor.AddSenderFee(tx), more txs will be removed from memory pool.

Since we already have UpdatePoolForBlockPersisted, and this TryAdd is called from a single thread (the Blockchain actor). We need to find the cause of this phenomenon.

neo/src/neo/Ledger/MemoryPool.cs

Lines 351 to 361 in fc1a64b

internal void UpdatePoolForBlockPersisted(Block block, StoreView snapshot)

{

bool policyChanged = LoadPolicy(snapshot);

_txRwLock.EnterWriteLock();

try

{

// First remove the transactions verified in the block.

foreach (Transaction tx in block.Transactions)

{

if (TryRemoveVerified(tx.Hash, out _)) continue;

This happend because it's not a single thread, Blockchain actor, but was send by RPC

https://github.com/neo-project/neo-modules/blob/ef91c522f13ef30bc6308a2e343a4c3466bb3885/src/RpcServer/RpcServer.Wallet.cs#L288

So we can add a lock in OnNewTransaction and check if it's solved

So we can add a lock in OnNewTransaction and check if it's solved

It doesn't work in my tests..

cloud8little

I can still get the error with one single CN, and the sender wallet with only one address.

[15:19:21.903] relay block: height=23 hash=0x35e977d9d7eeabc3e0e568cb9cc6590ebc378929d34fd283c32f19abb20e45c2 tx=0
[15:19:21.913] persist block: height=23 hash=0x35e977d9d7eeabc3e0e568cb9cc6590ebc378929d34fd283c32f19abb20e45c2 tx=0
[15:19:21.923] initialize: height=24 view=0 index=0 role=Primary
[15:19:36.922] timeout: height=24 view=0
[15:19:36.930] send prepare request: height=24 view=0
[15:19:36.954] send commit
[15:19:36.965] relay block: height=24 hash=0x85d722eecef7f7b1f8d0ac761e13f999ed27584f0abb1fc7336f9bc404cdd2ef tx=512
[ERROR][2020/1/16 7:19:37][Thread 0021][akka://NeoSystem/user/$a] Operation is not valid due to the current state of the object.
Cause: System.InvalidOperationException: Operation is not valid due to the current state of the object.
   at Neo.Ledger.Blockchain.Persist(Block block) in D:\NEO\Github\neo\src\neo\Ledger\Blockchain.cs:line 501
   at Neo.Ledger.Blockchain.OnNewBlock(Block block) in D:\NEO\Github\neo\src\neo\Ledger\Blockchain.cs:line 328
   at Neo.Ledger.Blockchain.OnReceive(Object message) in D:\NEO\Github\neo\src\neo\Ledger\Blockchain.cs:line 465
   at Akka.Actor.UntypedActor.Receive(Object message)
   at Akka.Actor.ActorBase.AroundReceive(Receive receive, Object message)
   at Akka.Actor.ActorCell.ReceiveMessage(Object message)
   at Akka.Actor.ActorCell.Invoke(Envelope envelope)
[ERROR][2020/1/16 7:19:37][Thread 0021][akka://NeoSystem/user/$a] Error while creating actor instance of type Neo.Ledger.Blockchain with 2 args: (Neo.NeoSystem,Neo.Plugins.Storage.Store)
Cause: [akka://NeoSystem/user/$a#1090028194]: Akka.Actor.PostRestartException: Exception post restart (System.InvalidOperationException)
 ---> System.TypeLoadException: Error while creating actor instance of type Neo.Ledger.Blockchain with 2 args: (Neo.NeoSystem,Neo.Plugins.Storage.Store)
 ---> System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation.
 ---> System.InvalidOperationException: Operation is not valid due to the current state of the object.
   at Neo.Ledger.Blockchain..ctor(NeoSystem system, IStore store) in D:\NEO\Github\neo\src\neo\Ledger\Blockchain.cs:line 111
   --- End of inner exception stack trace ---
   at System.RuntimeMethodHandle.InvokeMethod(Object target, Object[] arguments, Signature sig, Boolean constructor, Boolean wrapExceptions)
   at System.Reflection.RuntimeConstructorInfo.Invoke(BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture)
   at System.RuntimeType.CreateInstanceImpl(BindingFlags bindingAttr, Binder binder, Object[] args, CultureInfo culture)
   at System.Activator.CreateInstance(Type type, BindingFlags bindingAttr, Binder binder, Object[] args, CultureInfo culture, Object[] activationAttributes)
   at System.Activator.CreateInstance(Type type, Object[] args)
   at Akka.Actor.Props.ActivatorProducer.Produce()
   at Akka.Actor.Props.NewActor()
   --- End of inner exception stack trace ---
   at Akka.Actor.Props.NewActor()
   at Akka.Actor.ActorCell.CreateNewActorInstance()
   at Akka.Actor.ActorCell.<>c__DisplayClass109_0.<NewActor>b__0()
   at Akka.Actor.ActorCell.UseThreadContext(Action action)
   at Akka.Actor.ActorCell.NewActor()
   at Akka.Actor.ActorCell.FinishRecreate(Exception cause, ActorBase failedActor)
   --- End of inner exception stack trace ---

sender wallet with initial balance 100000 gas.
request:

{
  "jsonrpc": "2.0",
  "method": "sendtoaddress",
  "params": ["0x8c23f196d8a1bfd103a9dcb1f9ccf0c611377d3b", "NcnELA9BMsxDCzatGmTT5Tbq5dFTEXMarN",0.00000001],
  "id": 1
}

use jmeter to send 600 requests at one time.

Tommo-L · 2020-01-16T07:50:37Z

I'll help investigate this problem

shargon · 2020-01-16T07:55:02Z

@cloud8little thanks for your test, i spent half hour without issues and before the fix the issue was thrown in the first 4 blocks... I will review it more!

shargon · 2020-01-16T12:41:18Z

@cloud8little if you try to replicate your issue with multiple threads, you will get another error produced by parallel verification

src/neo/Ledger/MemoryPool.cs

eryeer

Good job, In this case the gas calculation error can be prevented.

vncoelho · 2020-01-17T10:17:21Z

src/neo/Ledger/MemoryPool.cs

            try
            {
+                // Check balance
+                BigInteger balance = NativeContract.GAS.BalanceOf(snapshot, tx.Sender);


In this sense, the key error was to not consider the current Balance of the sender, which is updated in parallel during OnPersist event?

I think so.

I think we should move the "balance check" to BlockChain.OnParallelVerified, which is right place to verify the transaction.

cloud8little · 2020-01-17T10:28:46Z

Test cases:

start a single CN
start a normal node connect to the CN.
withdraw the initial neo and gas.
send 100000 neo and 500 gas to a wallet a.json
send rpc requests, such as below; the goal is to send 400 requests at a time, and after 30 secs, send another 400 requests.

{
  "jsonrpc": "2.0",
  "method": "sendtoaddress",
  "params": ["0x9bde8f209c88dd0e7ca3bf0af0f476cdd8207789", "NcnELA9BMsxDCzatGmTT5Tbq5dFTEXMarN",1],
  "id": 1
}

Test result: [PASS]

CN is able to handle gas insufficient situation.
after requests are all dealt with, checked the account balance is correct.

erikzhang · 2020-01-17T15:11:38Z

I have told you that it is very dangerous to use multithreading in actors.

erikzhang · 2020-01-17T15:19:32Z

I think we can call tx.VerifyForEachBlock() in OnParallelVerified().

shargon · 2020-01-17T16:23:05Z

We need to check if after this changes, parallel will be faster

shargon · 2020-01-17T16:34:30Z

I think we can call tx.VerifyForEachBlock() in OnParallelVerified().

#1423 we can choose wich is the best one.

Fix

6779b51

shargon requested review from cloud8little, eryeer, erikzhang, belane and vncoelho January 15, 2020 14:04

Fix ut

0db1633

vncoelho reviewed Jan 15, 2020

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Tommo-L reviewed Jan 16, 2020

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cloud8little reviewed Jan 16, 2020

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shargon closed this Jan 16, 2020

shargon reopened this Jan 16, 2020

shargon mentioned this pull request Jan 16, 2020

Parallel verification issues #1420

Closed

Merge branch 'master' into fix-1410

c4de3ea

Tommo-L reviewed Jan 17, 2020

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src/neo/Ledger/MemoryPool.cs Outdated Show resolved Hide resolved

shargon added 2 commits January 17, 2020 09:19

Optimize

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Fix UT

780e1b6

eryeer reviewed Jan 17, 2020

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vncoelho reviewed Jan 17, 2020

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cloud8little approved these changes Jan 17, 2020

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shargon mentioned this pull request Jan 17, 2020

Fix Parallel verification issues (v2) #1423

Closed

shargon mentioned this pull request Jan 21, 2020

Remove parallel verification #1429

Merged

Merge branch 'master' into fix-1410

c898379

shargon changed the title ~~Fix Parallel verification issues~~ Fix Parallel verification issues (v1) Jan 21, 2020

erikzhang closed this Mar 3, 2020

shargon deleted the fix-1410 branch March 3, 2020 07:14

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Fix Parallel verification issues (v1) #1417

Fix Parallel verification issues (v1) #1417

shargon commented Jan 15, 2020 •

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shargon commented Jan 17, 2020

shargon commented Jan 17, 2020

	internal void UpdatePoolForBlockPersisted(Block block, StoreView snapshot)
	{
	bool policyChanged = LoadPolicy(snapshot);

	_txRwLock.EnterWriteLock();
	try
	{
	// First remove the transactions verified in the block.
	foreach (Transaction tx in block.Transactions)
	{
	if (TryRemoveVerified(tx.Hash, out _)) continue;

Fix Parallel verification issues (v1) #1417

Fix Parallel verification issues (v1) #1417

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