Sets the default value to the previous lookahead limit. My testing on
mainnet suggested that the newly lower value (changed when the
checkpoint frequency was decreased) is low enough to cause stalls, even
when using hedged requests.
Remove the minimum data points from the syncer hedge configuragtion.
When there are no data points, hedge sends the second request
immediately.
Where there are less than 1/(1-latency_percentile) data points (20),
hedge delays the second request by the highest recent download time.
This change should improve genesis and post-restart sync latency.
We should error if we notice that we're attempting to download the same
blocks multiple times, because that indicates that peers reported bad
information to us, or we got confused trying to interpret their
responses.
The original sync algorithm split the sync process into two phases, one
that obtained prospective chain tips, and another that attempted to
extend those chain tips as far as possible until encountering an error
(at which point the prospective state is discarded and the process
restarts).
Because a previous implementation of this algorithm didn't properly
enforce linkage between segments of the chain while extending tips,
sometimes it would get confused and fail to discard responses that did
not extend a tip. To mitigate this, a check against the state was
added. However, this check can cause stalls while checkpointing,
because when a checkpoint is reached we may suddenly need to commit
thousands of blocks to the state. Because the sync algorithm now has a
a `CheckedTip` structure that ensures that a new segment of hashes
actually extends an existing one, we don't need to check against the
state while extending a tip, because we don't get confused while
interpreting responses.
This change results in significantly smoother progress on mainnet.
There's no reason to return a pre-Buffer'd service (there's no need for
internal access to the state service, as in zebra-network), but wrapping
it internally removes control of the buffer size from the caller.
The timeout behavior in zebra-network is an implementation detail, not a
feature of the public API. So it shouldn't be mentioned in the doc
comments -- if we want timeout behavior, we have to layer it ourselves.
Using the cancel_handles, we can deduplicate requests. This is
important to do, because otherwise when we insert the second cancel
handle, we'd drop the first one, cancelling an existing task for no
reason.
The hedge middleware implements hedged requests, as described in _The
Tail At Scale_. The idea is that we auto-tune our retry logic according
to the actual network conditions, pre-emptively retrying requests that
exceed some latency percentile. This would hopefully solve the problem
where our timeouts are too long on mainnet and too slow on testnet.
Try to use the better cancellation logic to revert to previous sync
algorithm. As designed, the sync algorithm is supposed to proceed by
downloading state prospectively and handle errors by flushing the
pipeline and starting over. This hasn't worked well, because we didn't
previously cancel tasks properly. Now that we can, try to use something
in the spirit of the original sync algorithm.
This makes two changes relative to the existing download code:
1. It uses a oneshot to attempt to cancel the download task after it
has started;
2. It encapsulates the download creation and cancellation logic into a
Downloads struct.
* Reverse displayed endianness of transaction and block hashes
* fix zebra-checkpoints utility for new hash order
* Stop using "zebrad revhex" in zebrad-hash-lookup
* Rebuild checkpoint lists in new hash order
This change also adds additional checkpoints to the end of each list.
* Replace TransactionHash with transaction::Hash
This change should have been made in #905, but we missed Debug impls
and some docs.
Co-authored-by: Ramana Venkata <vramana@users.noreply.github.com>
Co-authored-by: teor <teor@riseup.net>
This reduces the API surface to the minimum required for functionality,
and cleans up module documentation. The stub mempool module is deleted
entirely, since it will need to be redone later anyways.
* implement most of the chain functions
* implement fork
* fix outpoint handling in Chain struct
* update expect for work
* split utxo into two sets
* update the Chain definition
* remove allow attribute in zebra-state/lib.rs
* merge ChainSet type into MemoryState
* Add error messages to asserts
* export proptest impls for use in downstream crates
* add testjob for disabled feature in zebra-chain
* try to fix github actions syntax
* add module doc comment
* update RFC for utxos
* add missing header
* working proptest for Chain
* propagate back results over channel
* Start updating RFC to match changes
* implement queued block pruning
* and now it syncs wooo!
* remove empty modules
* setup config for proptests
* re-enable missing_docs lint
* update RFC to match changes in impl
* add documentation
* use more explicit variable names
The Inbound service only needs the network setup for some requests, but
it can service other requests without it. Making it return
Poll::Pending until the network setup finishes means that initial
network connections may view the Inbound service as overloaded and
attempt to load-shed.
The original version of this commit ran into
https://github.com/rust-lang/rust/issues/64552
again. Thanks to @yaahc for suggesting a workaround (using futures combinators
to avoid writing an async block).
Remove the seed command entirely, and make the behavior it provided
(responding to `Request::Peers`) part of the ordinary functioning of the
start command.
The new `Inbound` service should be expanded to handle all request
types.
* increase the EWMA default and decay
* increase the block download retries
* increase the request and block download timeouts
* increase the sync timeout
* Ignore sync errors when the block is already verified
If we get an error for a block that is already in our state, we don't
need to restart the sync. It was probably a duplicate download.
Also:
Process any ready tasks before reset, so the logs and metrics are
up to date. (But ignore the errors, because we're about to reset.)
Improve sync logging and metrics during the download and verify task.
* Remove duplicate hashes in logs
Co-authored-by: Jane Lusby <jlusby42@gmail.com>
* Log the sync hash span at warn level
Co-authored-by: Jane Lusby <jlusby42@gmail.com>
* Remove in-memory state service
* make the config compatible with toml again
* checkpoint commit to see how much I still have to revert
* back to the starting point...
* remove unused dependency
* reorganize error handling a bit
* need to make a new color-eyre release now
* reorder again because I have problems
* remove unnecessary helpers
* revert changes to config loading
* add back missing space
* Switch to released color-eyre version
* add back missing newline again...
* improve error message on unix when terminated by signal
* add context to last few asserts in acceptance tests
* instrument some of the helpers
* remove accidental extra space
* try to make this compile on windows
* reorg platform specific code
* hide on_disk module and fix broken link
Alfredo Garcia
Henry de Valence
teor
Jane Lusby