* all: seperate consensus error and evm internal error
There are actually two types of error will be returned when
a tranaction/message call is executed: (a) consensus error
(b) evm internal error. The former should be converted to
a consensus issue, e.g. The sender doesn't enough asset to
purchase the gas it specifies. The latter is allowed since
evm itself is a blackbox and internal error is allowed to happen.
This PR emphasizes the difference by introducing a executionResult
structure. The evm error is embedded inside. So if any error
returned, it indicates consensus issue happens.
And also this PR improve the `EstimateGas` API to return the concrete
revert reason if the transaction always fails
* all: polish
* accounts/abi/bind/backends: add tests
* accounts/abi/bind/backends, internal: cleanup error message
* all: address comments
* core: fix lint
* accounts, core, eth, internal: address comments
* accounts, internal: resolve revert reason if possible
* accounts, internal: address comments
This new API allows reading accounts and their content by address range.
Co-authored-by: Martin Holst Swende <martin@swende.se>
Co-authored-by: Felix Lange <fjl@twurst.com>
* eth: improve shutdown synchronization
Most goroutines started by eth.Ethereum didn't have any shutdown sync at
all, which lead to weird error messages when quitting the client.
This change improves the clean shutdown path by stopping all internal
components in dependency order and waiting for them to actually be
stopped before shutdown is considered done. In particular, we now stop
everything related to peers before stopping 'resident' parts such as
core.BlockChain.
* eth: rewrite sync controller
* eth: remove sync start debug message
* eth: notify chainSyncer about new peers after handshake
* eth: move downloader.Cancel call into chainSyncer
* eth: make post-sync block broadcast synchronous
* eth: add comments
* core: change blockchain stop message
* eth: change closeBloomHandler channel type
Prior to this change, eth_call changed the balance of the sender account in the
EVM environment to 2^256 wei to cover the gas cost of the call execution.
We've had this behavior for a long time even though it's super confusing.
This commit sets the default call gasprice to zero instead of updating the balance,
which is better because it makes eth_call semantics less surprising. Removing
the built-in balance assignment also makes balance overrides work as expected.
* node: expose config in service context
* eth: integrate p2p/dnsdisc
* cmd/geth: add some DNS flags
* eth: remove DNS URLs
* cmd/utils: configure DNS names for testnets
* params: update DNS URLs
* cmd/geth: configure mainnet DNS
* cmd/utils: rename DNS flag and fix flag processing
* cmd/utils: remove debug print
* node: fix test
* travis: Enable ARM support
* Include fixes from 20039
* Add a trace to debug the invalid lookup issue
* Try increasing the timeout to see if the arm test passes
* Investigate the resolver issue
* Increase arm64 timeout for clique test
* increase timeout in tests for arm64
* Only test the failing tests
* Review feedback: don't export epsilon
* Remove investigation tricks+include fjl's feeback
* Revert the retry ahead of using the mock resolver
* Fix rebase errors
* core/evm, contracts: avoid copying memory for input in calls + make ecrecover not modify input buffer
* core/vm: optimize mstore a bit
* core/vm: change Get -> GetCopy in vm memory access
When we flush a batch of trie nodes into database during the state
sync, we should guarantee that all children should be flushed before
parent.
Actually the trie nodes commit order is strict by: children -> parent.
But when we flush all ready nodes into db, we don't need the order
anymore since
(1) they are all ready nodes (no more dependency)
(2) underlying database provides write atomicity
The precompile at 0x09 wraps the BLAKE2b F compression function:
https://tools.ietf.org/html/rfc7693#section-3.2
The precompile requires 6 inputs tightly encoded, taking exactly 213
bytes, as explained below.
- `rounds` - the number of rounds - 32-bit unsigned big-endian word
- `h` - the state vector - 8 unsigned 64-bit little-endian words
- `m` - the message block vector - 16 unsigned 64-bit little-endian words
- `t_0, t_1` - offset counters - 2 unsigned 64-bit little-endian words
- `f` - the final block indicator flag - 8-bit word
[4 bytes for rounds][64 bytes for h][128 bytes for m][8 bytes for t_0]
[8 bytes for t_1][1 byte for f]
The boolean `f` parameter is considered as `true` if set to `1`.
The boolean `f` parameter is considered as `false` if set to `0`.
All other values yield an invalid encoding of `f` error.
The precompile should compute the F function as specified in the RFC
(https://tools.ietf.org/html/rfc7693#section-3.2) and return the updated
state vector `h` with unchanged encoding (little-endian).
See EIP-152 for details.
* eth: chain config (genesis + fork) ENR entry
* core/forkid, eth: protocol independent fork ID, update to CRC32 spec
* core/forkid, eth: make forkid a struct, next uint64, enr struct, RLP
* core/forkid: change forkhash rlp encoding from int to [4]byte
* eth: fixup eth entry a bit and update it every block
* eth: fix lint
* eth: fix crash in ethclient tests
This PR adds some hardening in the lower levels of the protocol stack, to bail early on invalid data. Primarily, attacks that this PR protects against are on the "annoyance"-level, which would otherwise write a couple of megabytes of data into the log output, which is a bit resource intensive.
* core/state, cmd/geth: streaming json output dump cmd + optional code+storage
* dump: add option to continue even if preimages are missing
* core, evm: lint nits
* cmd: use local flags for dump, omit empty code/storage
* core/state: fix state dump test
* core, eth: some fixes for freezer
* vendor, core/rawdb, cmd/geth: add db inspector
* core, cmd/utils: check ancient store path forceily
* cmd/geth, common, core/rawdb: a few fixes
* cmd/geth: support windows file rename and fix rename error
* core: support ancient plugin
* core, cmd: streaming file copy
* cmd, consensus, core, tests: keep genesis in leveldb
* core: write txlookup during ancient init
* core: bump database version
* all: freezer style syncing
core, eth, les, light: clean up freezer relative APIs
core, eth, les, trie, ethdb, light: clean a bit
core, eth, les, light: add unit tests
core, light: rewrite setHead function
core, eth: fix downloader unit tests
core: add receipt chain insertion test
core: use constant instead of hardcoding table name
core: fix rollback
core: fix setHead
core/rawdb: remove canonical block first and then iterate side chain
core/rawdb, ethdb: add hasAncient interface
eth/downloader: calculate ancient limit via cht first
core, eth, ethdb: lots of fixes
* eth/downloader: print ancient disable log only for fast sync
* core, eth, trie: bloom filter for trie node dedup during fast sync
* eth/downloader, trie: address review comments
* core, ethdb, trie: restart fast-sync bloom construction now and again
* eth/downloader: initialize fast sync bloom on startup
* eth: reenable eth/62 until we properly remove it
This change makes getBalance, getCode, getStorageAt, getProof,
call, getTransactionCount return an error if the block number in
the request doesn't exist. getHeaderByNumber still returns null
for missing headers.
* cmd, eth, miner: disable advance sealing if user require
* cmd, console, miner, les, eth: wrap the miner config
* eth: remove todo
* cmd, miner: revert noadvance flag
The reason for this is: if the transaction execution is even longer
than block time, then this kind of transactions is DoS attack.
* core/vm: remove function call for stack validation from evm runloop
* core/vm: separate gas calc into static + dynamic
* core/vm: optimize push1
* core/vm: reuse pooled bigints for ADDRESS, ORIGIN and CALLER
* core/vm: use generic error message for jump/jumpi, to avoid string interpolation
* testdata: fix tests for new error message
* core/vm: use 64-bit memory calculations
* core/vm: fix error in memory calculation
* core/vm: address review concerns
* core/vm: avoid unnecessary use of big.Int:BitLen()
This change
- implements concurrent LES request serving even for a single peer.
- replaces the request cost estimation method with a cost table based on
benchmarks which gives much more consistent results. Until now the
allowed number of light peers was just a guess which probably contributed
a lot to the fluctuating quality of available service. Everything related
to request cost is implemented in a single object, the 'cost tracker'. It
uses a fixed cost table with a global 'correction factor'. Benchmark code
is included and can be run at any time to adapt costs to low-level
implementation changes.
- reimplements flowcontrol.ClientManager in a cleaner and more efficient
way, with added capabilities: There is now control over bandwidth, which
allows using the flow control parameters for client prioritization.
Target utilization over 100 percent is now supported to model concurrent
request processing. Total serving bandwidth is reduced during block
processing to prevent database contention.
- implements an RPC API for the LES servers allowing server operators to
assign priority bandwidth to certain clients and change prioritized
status even while the client is connected. The new API is meant for
cases where server operators charge for LES using an off-protocol mechanism.
- adds a unit test for the new client manager.
- adds an end-to-end test using the network simulator that tests bandwidth
control functions through the new API.
Simplifies the transaction presense check to use a function to
determine if the transaction is present in the block provided
to trace, which originally had a redundant parenthesis and used
a `exist` flag to dictate control flow.
This changes default location of the data directory to use the LOCALAPPDATA
environment variable, resolving issues with remote home directories an improving
compatibility with Cygwin.
Fixes#2239Fixes#2237Fixes#16437
* cmd, eth: Added in the flag to step geth once sync based on input
* cmd, eth: 16400 Add an option to stop geth once in sync.
* cmd: 16400 Add an option to stop geth once in sync. WIP
* cmd/geth/main, les/fletcher: added in light mode support
* cmd/geth/main, les/fletcher: Cleaned Comments and code for light mode
* cmd: 16400 Fixed formatting issue and cleaned code
* cmd, eth, les: 16400 Fixed formatting issues
* cmd, eth, les: Performed gofmt to update formatting
* cmd, eth, les: Fixed bugs resulting formatting
* cmd/geth, eth/, les: switched to downloader event
* eth: Fixed styling and gen_config
* eth/: Fix nil error in config file
* cmd/geth: Updated countdown log
* les/fetcher.go: Removed depcreated channel
* eth/downloader.go: Removed deprecated select
* cmd/geth, cmd/utils: Fixed minor issues
* eth: Reverted config files to proper format
* eth: Fixed typo in config file
* cmd/geth, eth/down: Updated code to use header time stamp
* eth/downloader: Changed the time threshold to 10 minutes
* cmd/geth, eth/downloader: Updated downloading event to pass latest header
* cmd/geth: Updated main to use right timer object
* cmd/geth: Removed unused failed event
* cmd/geth: added in correct time field with type assertion
* cmd/geth, cmd/utils: Updated flag to use boolean
* cmd/geth, cmd/utils, eth/downloader: Cleaned up code based on recommendations
* cmd/geth: Removed unneeded import
* cmd/geth, eth/downloader: fixed event field and suggested changes
* cmd/geth, cmd/utils: Updated flag and linting issue
* geth/core/eth: implement constantinople override flag
* les: implemnent constantinople override flag for les clients
* cmd/geth, eth, les: fix typo, move flag to experimentals
* Rejects peers that respond with a different hash for any of the passed in block numbers.
* Meant for emergency situations when the network forks unexpectedly.
Until this commit, when sending an RPC request that called `NewEVM`, a blank `vm.Config`
would be taken so as to set some options, based on the default configuration. If some extra
configuration switches were passed to the blockchain, those would be ignored.
This PR adds a function to get the config from the blockchain, and this is what is now used
for RPC calls.
Some subsequent changes need to be made, see https://github.com/ethereum/go-ethereum/pull/17955#pullrequestreview-182237244
for the details of the discussion.
* core: speed up GenerateChain
Use a mock implementation of ChainReader instead of creating
and destroying a BlockChain object for each generated block.
* eth/downloader: speed up tests by generating chain only once
This change reworks the downloader tests so they share a common test
blockchain instead of generating a chain in every test. The tests are
roughly twice as fast now.
This adds the global accumulated refund counter to the standard
json output as a numeric json value. Previously this was not very
interesting since it was not used much, but with the new sstore
gas changes the value is a lot more interesting from a consensus
investigation perspective.
Package p2p/enode provides a generalized representation of p2p nodes
which can contain arbitrary information in key/value pairs. It is also
the new home for the node database. The "v4" identity scheme is also
moved here from p2p/enr to remove the dependency on Ethereum crypto from
that package.
Record signature handling is changed significantly. The identity scheme
registry is removed and acceptable schemes must be passed to any method
that needs identity. This means records must now be validated explicitly
after decoding.
The enode API is designed to make signature handling easy and safe: most
APIs around the codebase work with enode.Node, which is a wrapper around
a valid record. Going from enr.Record to enode.Node requires a valid
signature.
* p2p/discover: port to p2p/enode
This ports the discovery code to the new node representation in
p2p/enode. The wire protocol is unchanged, this can be considered a
refactoring change. The Kademlia table can now deal with nodes using an
arbitrary identity scheme. This requires a few incompatible API changes:
- Table.Lookup is not available anymore. It used to take a public key
as argument because v4 protocol requires one. Its replacement is
LookupRandom.
- Table.Resolve takes *enode.Node instead of NodeID. This is also for
v4 protocol compatibility because nodes cannot be looked up by ID
alone.
- Types Node and NodeID are gone. Further commits in the series will be
fixes all over the the codebase to deal with those removals.
* p2p: port to p2p/enode and discovery changes
This adapts package p2p to the changes in p2p/discover. All uses of
discover.Node and discover.NodeID are replaced by their equivalents from
p2p/enode.
New API is added to retrieve the enode.Node instance of a peer. The
behavior of Server.Self with discovery disabled is improved. It now
tries much harder to report a working IP address, falling back to
127.0.0.1 if no suitable address can be determined through other means.
These changes were needed for tests of other packages later in the
series.
* p2p/simulations, p2p/testing: port to p2p/enode
No surprises here, mostly replacements of discover.Node, discover.NodeID
with their new equivalents. The 'interesting' API changes are:
- testing.ProtocolSession tracks complete nodes, not just their IDs.
- adapters.NodeConfig has a new method to create a complete node.
These changes were needed to make swarm tests work.
Note that the NodeID change makes the code incompatible with old
simulation snapshots.
* whisper/whisperv5, whisper/whisperv6: port to p2p/enode
This port was easy because whisper uses []byte for node IDs and
URL strings in the API.
* eth: port to p2p/enode
Again, easy to port because eth uses strings for node IDs and doesn't
care about node information in any way.
* les: port to p2p/enode
Apart from replacing discover.NodeID with enode.ID, most changes are in
the server pool code. It now deals with complete nodes instead
of (Pubkey, IP, Port) triples. The database format is unchanged for now,
but we should probably change it to use the node database later.
* node: port to p2p/enode
This change simply replaces discover.Node and discover.NodeID with their
new equivalents.
* swarm/network: port to p2p/enode
Swarm has its own node address representation, BzzAddr, containing both
an overlay address (the hash of a secp256k1 public key) and an underlay
address (enode:// URL).
There are no changes to the BzzAddr format in this commit, but certain
operations such as creating a BzzAddr from a node ID are now impossible
because node IDs aren't public keys anymore.
Most swarm-related changes in the series remove uses of
NewAddrFromNodeID, replacing it with NewAddr which takes a complete node
as argument. ToOverlayAddr is removed because we can just use the node
ID directly.
Interpreter initialization is left to the PRs implementing them.
Options for external interpreters are passed after a colon in the
`--vm.ewasm` and `--vm.evm` switches.
Makes Interface interface a bit more stateless and abstract.
Obviously this change is dictated by EVMC design. The EVMC tries to keep the responsibility for EVM features totally inside the VMs, if feasible. This makes VM "stateless" because VM does not need to pass any information between executions, all information is included in parameters of the execute function.
This PR enables the indexers to work in light client mode by
downloading a part of these tries (the Merkle proofs of the last
values of the last known section) in order to be able to add new
values and recalculate subsequent hashes. It also adds CHT data to
NodeInfo.
* consensus/ethash: start remote ggoroutine to handle remote mining
* consensus/ethash: expose remote miner api
* consensus/ethash: expose submitHashrate api
* miner, ethash: push empty block to sealer without waiting execution
* consensus, internal: add getHashrate API for ethash
* consensus: add three method for consensus interface
* miner: expose consensus engine running status to miner
* eth, miner: specify etherbase when miner created
* miner: commit new work when consensus engine is started
* consensus, miner: fix some logics
* all: delete useless interfaces
* consensus: polish a bit
The current trie memory database/cache that we do pruning on stores
trie nodes as binary rlp encoded blobs, and also stores the node
relationships/references for GC purposes. However, most of the trie
nodes (everything apart from a value node) is in essence just a
collection of references.
This PR switches out the RLP encoded trie blobs with the
collapsed-but-not-serialized trie nodes. This permits most of the
references to be recovered from within the node data structure,
avoiding the need to track them a second time (expensive memory wise).
This removes a golint warning: type name will be used as trie.TrieSync by
other packages, and that stutters; consider calling this Sync.
In hexToKeybytes len(hex) is even and (even+1)/2 == even/2, remove the +1.
* common: delete StringToAddress, StringToHash
These functions are confusing because they don't parse hex, but use the
bytes of the string. This change removes them, replacing all uses of
StringToAddress(s) by BytesToAddress([]byte(s)).
* eth/filters: remove incorrect use of common.BytesToAddress
The first should address a long term issue where we recommend a gas
price that is greater than that required for 50% of transactions in
recent blocks, which can lead to gas price inflation as people take
this figure and add a margin to it, resulting in a positive feedback
loop.
* core/types, core/vm, eth, tests: regenerate gencodec files
* Makefile: update devtools target
Install protoc-gen-go and print reminders about npm, solc and protoc.
Also switch to github.com/kevinburke/go-bindata because it's more
maintained.
* contracts/ens: update contracts and regenerate with solidity v0.4.19
The newer upstream version of the FIFSRegistrar contract doesn't set the
resolver anymore. The resolver is now deployed separately.
* contracts/release: regenerate with solidity v0.4.19
* contracts/chequebook: fix fallback and regenerate with solidity v0.4.19
The contract didn't have a fallback function, payments would be rejected
when compiled with newer solidity. References to 'mortal' and 'owned'
use the local file system so we can compile without network access.
* p2p/discv5: regenerate with recent stringer
* cmd/faucet: regenerate
* dashboard: regenerate
* eth/tracers: regenerate
* internal/jsre/deps: regenerate
* dashboard: avoid sed -i because it's not portable
* accounts/usbwallet/internal/trezor: fix go generate warnings
Updated use of Parallel and added some subtests to help isolate
them. Increased timeout in RequestHeadersByNumber so it
doesn't time out and causes other tests to break.
* cmd, consensus, eth: split ethash related config to it own
* eth, consensus: minor polish
* eth, consenus, console: compress pow testing config field to single one
* consensus, eth: document pow mode
* eth, internal: Implement using trie diffs
* eth, internal: Changes in response to review
* eth: More fixes to getModifiedAccountsBy*
* eth: minor polishes on error capitalization
This PR implements the new LES protocol version extensions:
* new and more efficient Merkle proofs reply format (when replying to
a multiple Merkle proofs request, we just send a single set of trie
nodes containing all necessary nodes)
* BBT (BloomBitsTrie) works similarly to the existing CHT and contains
the bloombits search data to speed up log searches
* GetTxStatusMsg returns the inclusion position or the
pending/queued/unknown state of a transaction referenced by hash
* an optional signature of new block data (number/hash/td) can be
included in AnnounceMsg to provide an option for "very light
clients" (mobile/embedded devices) to skip expensive Ethash check
and accept multiple signatures of somewhat trusted servers (still a
lot better than trusting a single server completely and retrieving
everything through RPC). The new client mode is not implemented in
this PR, just the protocol extension.
When implementing the new bloombits based filter, I've accidentally broke null
topics by removing the special casing of common.Hash{} filter rules, which
acted as the wildcard topic until now.
This PR fixes the regression, but instead of using the magic hash
common.Hash{} as the null wildcard, the PR reworks the code to handle nil
topics during parsing, converting a JSON null into nil []common.Hash topic.
* ethdb: add Putter interface and Has method
* ethdb: improve docs and add IdealBatchSize
* ethdb: remove memory batch lock
Batches are not safe for concurrent use.
* core: use ethdb.Putter for Write* functions
This covers the easy cases.
* core/state: simplify StateSync
* trie: optimize local node check
* ethdb: add ValueSize to Batch
* core: optimize HasHeader check
This avoids one random database read get the block number. For many uses
of HasHeader, the expectation is that it's actually there. Using Has
avoids a load + decode of the value.
* core: write fast sync block data in batches
Collect writes into batches up to the ideal size instead of issuing many
small, concurrent writes.
* eth/downloader: commit larger state batches
Collect nodes into a batch up to the ideal size instead of committing
whenever a node is received.
* core: optimize HasBlock check
This avoids a random database read to get the number.
* core: use numberCache in HasHeader
numberCache has higher capacity, increasing the odds of finding the
header without a database lookup.
* core: write imported block data using a batch
Restore batch writes of state and add blocks, tx entries, receipts to
the same batch. The change also simplifies the miner.
This commit also removes posting of logs when a forked block is imported.
* core: fix DB write error handling
* ethdb: use RLock for Has
* core: fix HasBlock comment
* core: reduce txpool event loop goroutines and sync structs
* cmd, core, eth: journal local transactions to disk
* core: journal replacement pending transactions too
* core: separate transaction journal from pool
* core: remove redundant storage of transactions and receipts
* core, eth, internal: new transaction schema usage polishes
* eth: implement upgrade mechanism for db deduplication
* core, eth: drop old sequential key db upgrader
* eth: close last iterator on successful db upgrage
* core: prefix the lookup entries to make their purpose clearer
With this commit, core/state's access to the underlying key/value database is
mediated through an interface. Database errors are tracked in StateDB and
returned by CommitTo or the new Error method.
Motivation for this change: We can remove the light client's duplicated copy of
core/state. The light client now supports node iteration, so tracing and storage
enumeration can work with the light client (not implemented in this commit).
* eth/downloader: separate state sync from queue
Scheduling of state node downloads hogged the downloader queue lock when
new requests were scheduled. This caused timeouts for other requests.
With this change, state sync is fully independent of all other downloads
and doesn't involve the queue at all.
State sync is started and checked on in processContent. This is slightly
awkward because processContent doesn't have a select loop. Instead, the
queue is closed by an auxiliary goroutine when state sync fails. We
tried several alternatives to this but settled on the current approach
because it's the least amount of change overall.
Handling of the pivot block has changed slightly: the queue previously
prevented import of pivot block receipts before the state of the pivot
block was available. In this commit, the receipt will be imported before
the state. This causes an annoyance where the pivot block is committed
as fast block head even when state downloads fail. Stay tuned for more
updates in this area ;)
* eth/downloader: remove cancelTimeout channel
* eth/downloader: retry state requests on timeout
* eth/downloader: improve comment
* eth/downloader: mark peers idle when state sync is done
* eth/downloader: move pivot block splitting to processContent
This change also ensures that pivot block receipts aren't imported
before the pivot block itself.
* eth/downloader: limit state node retries
* eth/downloader: improve state node error handling and retry check
* eth/downloader: remove maxStateNodeRetries
It fails the sync too much.
* eth/downloader: remove last use of cancelCh in statesync.go
Fixes TestDeliverHeadersHang*Fast and (hopefully)
the weird cancellation behaviour at the end of fast sync.
* eth/downloader: fix leak in runStateSync
* eth/downloader: don't run processFullSyncContent in LightSync mode
* eth/downloader: improve comments
* eth/downloader: fix vet, megacheck
* eth/downloader: remove unrequested tasks anyway
* eth/downloader, trie: various polishes around duplicate items
This commit explicitly tracks duplicate and unexpected state
delieveries done against a trie Sync structure, also adding
there to import info logs.
The commit moves the db batch used to commit trie changes one
level deeper so its flushed after every node insertion. This
is needed to avoid a lot of duplicate retrievals caused by
inconsistencies between Sync internals and database. A better
approach is to track not-yet-written states in trie.Sync and
flush on commit, but I'm focuing on correctness first now.
The commit fixes a regression around pivot block fail count.
The counter previously was reset to 1 if and only if a sync
cycle progressed (inserted at least 1 entry to the database).
The current code reset it already if a node was delivered,
which is not stong enough, because unless it ends up written
to disk, an attacker can just loop and attack ad infinitum.
The commit also fixes a regression around state deliveries
and timeouts. The old downloader tracked if a delivery is
stale (none of the deliveries were requestedt), in which
case it didn't mark the node idle and did not send further
requests, since it signals a past timeout. The current code
did mark it idle even on stale deliveries, which eventually
caused two requests to be in flight at the same time, making
the deliveries always stale and mass duplicating retrievals
between multiple peers.
* eth/downloader: fix state request leak
This commit fixes the hang seen sometimes while doing the state
sync. The cause of the hang was a rare combination of events:
request state data from peer, peer drops and reconnects almost
immediately. This caused a new download task to be assigned to
the peer, overwriting the old one still waiting for a timeout,
which in turned leaked the requests out, never to be retried.
The fix is to ensure that a task assignment moves any pending
one back into the retry queue.
The commit also fixes a regression with peer dropping due to
stalls. The current code considered a peer stalling if they
timed out delivering 1 item. However, the downloader never
requests only one, the minimum is 2 (attempt to fine tune
estimated latency/bandwidth). The fix is simply to drop if
a timeout is detected at 2 items.
Apart from the above bugfixes, the commit contains some code
polishes I made while debugging the hang.
* core, eth, trie: support batched trie sync db writes
* trie: rename SyncMemCache to syncMemBatch
