Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

(6/6) [BUGFIX] Fix duplicate sequence number use case (Non-persistent ProtectedStoragePayloads) #3665

Merged
merged 18 commits into from Nov 26, 2019

Conversation

julianknutsen
Copy link
Contributor

@julianknutsen julianknutsen commented Nov 22, 2019

Fixes: #3679

3d571c4

Fix a bug introduced in d484617 that
did not properly handle a valid use case for duplicate sequence numbers.

For in-memory-only ProtectedStoragePayloads, the client nodes need a way
to reconstruct the Payloads after startup from peer and seed nodes. This
involves sending a ProtectedStorageEntry with a sequence number that
is equal to the last one the client had already seen.

This patch adds tests to confirm the bug and fix as well as the changes
necessary to allow adding of Payloads that were previously seen, but
removed during a restart.

Instead of using a subclass that overwrites a value, utilize Guice
to inject the real value of 10000 in the app and let the tests overwrite
it with their own.
Remove unused imports and clean up some access modifiers now that
the final test structure is complete
Previously, this interface was called each time an item was changed. This
required listeners to understand performance implications of multiple
adds or removes in a short time span.

Instead, give each listener the ability to process a list of added or
removed entrys which can help them avoid performance issues.

This patch is just a refactor. Each listener is called once for each
ProtectedStorageEntry. Future patches will change this.
Minor performance overhead for constructing MapEntry and Collections
of one element, but keeps the code cleaner and all removes can still
use the same logic to remove from map, delete from data store, signal
listeners, etc.

The MapEntry type is used instead of Pair since it will require less
operations when this is eventually used in the removeExpiredEntries path.
…batch

All current users still call this one-at-a-time. But, it gives the ability
for the expire code path to remove in a batch.
This will cause HashMapChangedListeners to receive just one onRemoved()
call for the expire work instead of multiple onRemoved() calls for each
item.

This required a bit of updating for the remove validation in tests so
that it correctly compares onRemoved with multiple items.
…ch removes

bisq-network#3143 identified an issue that tempProposals listeners were being
signaled once for each item that was removed during the P2PDataStore
operation that expired old TempProposal objects. Some of the listeners
are very expensive (ProposalListPresentation::updateLists()) which results
in large UI performance issues.

Now that the infrastructure is in place to receive updates from the
P2PDataStore in a batch, the ProposalService can apply all of the removes
received from the P2PDataStore at once. This results in only 1 onChanged()
callback for each listener.

The end result is that updateLists() is only called once and the performance
problems are reduced.

This removes the need for bisq-network#3148 and those interfaces will be removed in
the next patch.
Now that the only user of this interface has been removed, go ahead
and delete it. This is a partial revert of
f5d75c4 that includes the code that was
added into ProposalService that subscribed to the P2PDataStore.
Write a test that shows the incorrect behavior for bisq-network#3629, the hashmap
is rebuilt from disk using the 20-byte key instead of the 32-byte key.
Addresses the first half of bisq-network#3629 by ensuring that the reconstructed
HashMap always has the 32-byte key for each payload.

It turns out, the TempProposalStore persists the ProtectedStorageEntrys
on-disk as a List and doesn't persist the key at all. Then, on
reconstruction, it creates the 20-byte key for its internal map.

The fix is to update the TempProposalStore to use the 32-byte key instead.
This means that all writes, reads, and reconstrution of the TempProposalStore
uses the 32-byte key which matches perfectly with the in-memory map
of the P2PDataStorage that expects 32-byte keys.

Important to note that until all seednodes receive this update, nodes
will continue to have both the 20-byte and 32-byte keys in their HashMap.
Addresses the second half of bisq-network#3629 by using the HashMap, not the
protectedDataStore to generate the known keys in the requestData path.

This won't have any bandwidth reduction until all seednodes have the
update and only have the 32-byte key in their HashMap.

fixes bisq-network#3629
The only user has been migrated to getMap(). Delete it so future
development doesn't have the same 20-byte vs 32-byte key issue.
In order to implement remove-before-add behavior, we need a way to
verify that the SequenceNumberMap was the only item updated.
It is possible to receive a RemoveData or RemoveMailboxData message
before the relevant AddData, but the current code does not handle
it.

This results in internal state updates and signal handler's being called
when an Add is received with a lower sequence number than a previously
seen Remove.

Minor test validation changes to allow tests to specify that only the
SequenceNumberMap should be written during an operation.
Now that we have introduced remove-before-add, we need a way
to validate that the SequenceNumberMap was written, but nothing
else. Add this feature to the validation path.
In order to aid in propagation of remove() messages, broadcast them
in the event the remove is seen before the add.
Now that there are cases where the SequenceNumberMap and Broadcast
are called, but no other internal state is updated, the existing helper
functions conflate too many decisions. Remove them in favor of explicitly
defining each state change expected.
@@ -188,15 +188,5 @@ public void removeExpiredEntries_PurgeSeqNrMap() throws CryptoException, NoSuchA
SavedTestState beforeState = this.testState.saveTestState(purgedProtectedStorageEntry);
this.testState.mockedStorage.removeExpiredEntries();
this.testState.verifyProtectedStorageRemove(beforeState, expectedRemoves, true, true, false, false, false);

Copy link
Contributor Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

This test was testing too much when just calling verifyProtectedStorageRemove() gives us what we want.

But, the failure did point out that we add expirable ProtectedStorageEntrys and then immediately expire them in the next expire cycle. I'll put this on my backlog to fix it. Not super urgent.

Fix a bug introduced in d484617 that
did not properly handle a valid use case for duplicate sequence numbers.

For in-memory-only ProtectedStoragePayloads, the client nodes need a way
to reconstruct the Payloads after startup from peer and seed nodes. This
involves sending a ProtectedStorageEntry with a sequence number that
is equal to the last one the client had already seen.

This patch adds tests to confirm the bug and fix as well as the changes
necessary to allow adding of Payloads that were previously seen, but
removed during a restart.
@julianknutsen julianknutsen changed the title (7/7) [BUGFIX] Fix duplicate sequence number use case (Non-persistent ProtectedStoragePayloads) (6/7) [BUGFIX] Fix duplicate sequence number use case (Non-persistent ProtectedStoragePayloads) Nov 25, 2019
@julianknutsen julianknutsen changed the title (6/7) [BUGFIX] Fix duplicate sequence number use case (Non-persistent ProtectedStoragePayloads) (6/6) [BUGFIX] Fix duplicate sequence number use case (Non-persistent ProtectedStoragePayloads) Nov 25, 2019
Copy link
Member

@freimair freimair left a comment

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Ack

Copy link
Member

@ripcurlx ripcurlx left a comment

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

utACK

@ripcurlx ripcurlx merged commit 3d571c4 into bisq-network:master Nov 26, 2019
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
Labels
None yet
Projects
None yet
Development

Successfully merging this pull request may close these issues.

Attempting to create offer encounters error "There are no arbitrators available"
3 participants