This PR fixes two issues with block publishing:
* Gossip-valid blocks are published before integrating them into the
chain, giving broadcasting a head start, both for rest block and
* Outright invalid blocks from the API that could lead to the descoring
of the node are no longer broadcast
Bonus:
* remove undocumented and duplicated `post_v1_validator_block` JSON-RPC
call
* Support starting from altair
* hide `finalized-checkpoint-` - they are incomplete and usage may cause
crashes
* remove genesis detection code (broken, obsolete)
* enable starting ChainDAG from altair checkpoints - this is a
prerequisite for checkpoint sync (TODO: backfill)
* tighten checkpoint state conditions
* show error when starting from checkpoint with existing database (not
supported)
* print rest-compatible JSON in ncli/state_sim
* altair/merge support in ncli
* more altair/merge support in ncli_db
* pre-load header to speed up loading
* fix forked block decoding
* Address review comments in #3057
* reorder imports in rest_utils
maybe this will help with the mysterious serialization issues
Co-authored-by: Jacek Sieka <jacek@status.im>
According to the spec, this call should return the positions of
the specified validators within the sync committee. The existing
code was instead returning the indices of the sync sub-committees
where the validator is a member.
* fix stack overflow crash in REST/debug/getStateV2
* introduce `ForkyXxx` for generic type matching of `Xxx` across
branches (SomeHashedBeaconState -> ForkyHashedBeaconState et al) -
`Some` is already used for other types of type classes
* consolidate function naming in BeaconChainDB, use some generics
* import `forks.nim` from other spec modules and move `Forked*` helpers
around to resolve circular imports
* remove `ForkedBeaconState`, use `ForkedHashedBeaconState` throughout
(less data shuffling between the types)
* fix several cases of states being stored on stack in tests, causing
random failures on some platforms
* remove reading json support from ncli - this should be ported to the
rest json reading instead (doesn't currently work because stack sizes)
So far, the REST config response did not include all spec constants.
The spec for `/eth/v1/config/spec` defines that the response should
include constants for all hard forks known by the beacon node. This
patch extends the corresponding response to include more constants.
* Add `child_id` field.
* Fix json-rpc api call and bump chronos.
* Bump chronos master and fix compilation warnings.
* One more bump of `chronos`.
* add random import
* export rest_utils a bit more
Co-authored-by: Jacek Sieka <jacek@status.im>
* auto-bump nim-libp2p
* Remove peer info for other peers
Not definitive, just to test the libp2p's unstable branch
* finish up Remove peer info for other peers
* getKey -> getPublicKey
* bump libp2p
* libp2p bump
Co-authored-by: = <Menduist@users.noreply.github.com>
Co-authored-by: Tanguy <tanguy@status.im>
* `SyncCommitteeIndex` -> `SyncSubcommitteeIndex`
* `syncCommitteePeriod` -> `sync_committee_period` (spec spelling)
* tighten period comparisons
* fix assert when validating committee message with non-altair state in
REST api
* register vc duties with subnet tracker
* fix activation logging during startup
* cache slot signature to avoid duplicate signature work
* schedule aggregation duties one slot at a time to avoid CPU spike at
each epoch
* lower aggregation subnet pre-subscription time to 4 slots (lowers
bandwidth and CPU usage)
* update stability subnets in ENR on startup
* log gossip state
* perform gossip subscriptions just before the next slot starts
* document stuff
* add random include
* don't overwrite subscription state when not subscribed
* log target gossip state
* updating gossip status once is enough
* add test
* remove syncQueueLen - this one is not updated at the end of the sync
and may cause gossip to disconnect itself completely - use a simple head
distance instead
* fix gossip disconnection - if in hysteresis, node.gossipState will be
set to disabled even though we don't disable topic subscriptions
* fix extra duty registration call
* Initial commit.
* Fix path.
* Add validator keys to indices cache mechanism.
Move syncComitteeParticipants to common place.
* Fix sync participants order issue.
* Fix error code when state could not be found.
Refactor `state/validators` to use keysToIndices mechanism.
* Fix RestValidatorIndex to ValidatorIndex conversion TODOs.
* Address review comments.
* Fix REST test rules.
So far, `withState` and `withBlck` templates could only be used to have
convenience access to fork-agnostic BeaconState and BeaconBlock fields.
This patch:
- injects an additional `stateFork` constant that allows to use
`when` expressions to also access Altair and Merge-specific fields.
- introduces a `withStateAndBlck` template to support operating on both
a `BeaconState` and `BeaconBlock` at a time.
- makes sync committee related functions Merge aware.
- changes a couple if-else trees for forks into case statements so that
forgotten future forks are promoted to compile-time errors.
There are still a few cases with manual loops through sync subcommittees
even though an `allSyncCommittees` iterator exists. Adjusted the few
remaining instances to also use the iterator instead.
* Placing callbacks into strategic places.
* Initial events call implementation.
* Post rebase fixes.
* Change addSyncContribution() implementation.
* Add `attestation-sent` event.
Remove gcsafe, raises from callbacks implementations.
Move `attestation-received` fire at the end of attestation processing.
* Address review comments.
* cleanups
* use ForkedTrustedSignedBeaconBlock.ionit where appropriate
* move `is_aggregator` to `spec/`
* use `errReject` in a few more places
* update enr fork id when time is auspicious
* use network broadcast functions
* Return Ignore for aggregate signature validation timeouts
...consistently between aggregates and attestations.
* clean up some more reject/ignore rules
* shorten texts a bit
* errReject->checkedReject, use err helpers throughout
* get rid of quarantine in exitpool as well
* Fix getForkSchedule call.
Create cache of all configuration endpoints at node startup.
Add prepareJsonResponse() call to create cached responses.
Mark all procedures with `raises`.
* Add getForkSchedule to VC.
Fix getForkSchedule return type for API.
More `raises` annotations.
Fix VC fork_service.nim.
* Use `push raises` instead of inline `raises`.
* Improvements for REST API aggregated attestations and attestations processing.
* Rename eth2_network.sendXXX procedures to eth2_network.broadcastXXX.
Add broadcastBeaconBlock() and broadcastAggregateAndProof().
Fix links to specification in REST API declarations.
Add implementation for v2 getStateV2().
Add validator_duties.sendXXX procedures which not only broadcast data, but also validate it.
Fix JSON-RPC/REST to use new validator_duties.sendXXX procedures instead of own implementations.
* Fix validator_client online nodes count incorrect value.
Fix aggregate and proof attestation could be sent too late.
* Adding timeout for block wait in attestations processing.
Fix compilation errors.
* Attempt to debug aggregate and proofs.
* Fix Beacon AIP to use `sendAttestation`.
Add link comment to produceBlockV2.
* Add debug logs before publish operation for blocks, attestations and aggregated attestations.
Fix attestations publishing issue.
* logging fixes
`indexInCommnittee` already logged in attestation
Co-authored-by: Jacek Sieka <jacek@status.im>
* send attestations and exit messages on fork-appropriate topic
* document why use wall clock over attestation slot
* centralize some fork-topic-picking-logic in eth2_network
* pick up new test in summary
* allow specified GetTimeFn for testing purposes
* add GenesisTime and use it in eth2_network
* replace GetTimeFn and GenesisTime with GetBeaconTimeFn
* reorganize ssz dependencies
This PR continues the work in
https://github.com/status-im/nimbus-eth2/pull/2646,
https://github.com/status-im/nimbus-eth2/pull/2779 as well as past
issues with serialization and type, to disentangle SSZ from eth2 and at
the same time simplify imports and exports with a structured approach.
The principal idea here is that when a library wants to introduce SSZ
support, they do so via 3 files:
* `ssz_codecs` which imports and reexports `codecs` - this covers the
basic byte conversions and ensures no overloads get lost
* `xxx_merkleization` imports and exports `merkleization` to specialize
and get access to `hash_tree_root` and friends
* `xxx_ssz_serialization` imports and exports `ssz_serialization` to
specialize ssz for a specific library
Those that need to interact with SSZ always import the `xxx_` versions
of the modules and never `ssz` itself so as to keep imports simple and
safe.
This is similar to how the REST / JSON-RPC serializers are structured in
that someone wanting to serialize spec types to REST-JSON will import
`eth2_rest_serialization` and nothing else.
* split up ssz into a core library that is independendent of eth2 types
* rename `bytes_reader` to `codec` to highlight that it contains coding
and decoding of bytes and native ssz types
* remove tricky List init overload that causes compile issues
* get rid of top-level ssz import
* reenable merkleization tests
* move some "standard" json serializers to spec
* remove `ValidatorIndex` serialization for now
* remove test_ssz_merkleization
* add tests for over/underlong byte sequences
* fix broken seq[byte] test - seq[byte] is not an SSZ type
There are a few things this PR doesn't solve:
* like #2646 this PR is weak on how to handle root and other
dontSerialize fields that "sometimes" should be computed - the same
problem appears in REST / JSON-RPC etc
* Fix a build problem on macOS
* Another way to fix the macOS builds
Co-authored-by: Zahary Karadjov <zahary@gmail.com>
The spec imports are a mess to work with, so this branch cleans them up
a bit to ensure that we avoid generic sandwitches and that importing
stuff generally becomes easier.
* reexport crypto/digest/presets because these are part of the public
symbol set of the rest of the spec types
* don't export `merge` types from `base` - this causes circular deps
* fix circular deps in `ssz/spec_types` - this is the first step in
disentangling ssz from spec
* be explicit about phase0 vs altair - longer term, `altair` will become
the "natural" type set, then merge and so on, so no point in giving
`phase0` special preferential treatment
Simpler module name for stuff that covers forks
* check that runtime config matches database state
* also include some assorted altair cleanups
* use "standard" genesis fork in local testnet to work around missing
runtime config support
This refactoring puts the JSON-RPC and REST APIs on more equal footing
by renaming and moving things around, creating a separation between
client and server, and documenting what they are - the aim is to have a
simple-to-use base to start from when developing API clients, as well as
make it easier to navigate the code when looking for the legacy JSON-RPC
interface vs the new REST API.
* move REST client, serialization and supporting types to spec/eth2_apis
* REST stuff now starts with `rest_`, JSON-RPC stuff starts with `rpc_`,
more or less
* simplify imports such that there's a simple module to import for both
server and client
* map REST type and proc names to yaml spec more closely - in
particular, reuse operation and type names in `rest_types` to make
comparisons against spec more easy
* cleaner separation between client and server modules - modules common
between server and client such as `rest_types` and serialization move to
the spec folder - this allows the client to be built with less knowledge
about server internals
* some whole-file copies from altair branch
* rpc/node_api and rpc/node_rest_api also need to be copied
* remove new sync committee-related functionality
* bump libp2p
* altair sync v2
Use V2 sync requests after the altair fork has happened, according to
the wall clock
* Fix the behavior of the v1 req/resp calls after Altair
Co-authored-by: Zahary Karadjov <zahary@gmail.com>
* Initial commit.
* Exporting getConfig().
* Add beacon node checking procedures.
* Post rebase fixes.
* Use runSlotLoop() from nimbus_beacon_node.
Fallback implementation.
Fixes for ETH2 REST serialization.
* Add beacon_clock.durationToNextSlot().
Move type declarations from beacon_rest_api to json_rest_serialization.
Fix seq[ValidatorIndex] serialization.
Refactor ValidatorPool and add some utility procedures.
Create separate version of validator_client.
* Post-rebase fixes.
Remove CookedPubKey from validator_pool.nim.
* Now we should be able to produce attestations and aggregate and proofs.
But its not working yet.
* Debugging attestation sending.
* Add durationToNextAttestation.
Optimize some debug logs.
Fix aggregation_bits encoding.
Bump chronos/presto.
* Its alive.
* Fixes for launch_local_testnet script.
Bump chronos.
* Switch client API to not use `/api` prefix.
* Post-rebase adjustments.
* Fix endpoint for publishBlock().
* Add CONFIG_NAME.
Add more checks to ensure that beacon_node is compatible.
* Add beacon committee subscription support to validator_client.
* Fix stacktrace should be an array of strings.
Fix committee subscriptions should not be `data` keyed.
* Log duration to next block proposal.
* Fix beacon_node_status import.
* Use jsonMsgResponse() instead of jsonError().
* Fix graffityBytes usage.
Remove unnecessary `await`.
Adjust creation of SignedBlock instance.
Remove legacy files.
* Rework durationToNextSlot() and durationToNextEpoch() to use `fromNow`.
* Fix race condition for block proposal and attestations for same slot.
Fix local_testnet script to properly kill tasks on Windows.
Bump chronos and nim-http-tools, to allow connections to infura.io (basic auth).
* Catch services errors.
Improve performance of local_testnet.sh script on Windows.
Fix race condition when attestation producing.
* Post-rebase fixes.
* Bump chronos and presto.
* Calculate block publishing delay.
Fix pkill in one more place.
* Add error handling and timeouts to firstSuccess() template.
Add onceToAll() template.
Add checkNodes() procedure.
Refactor firstSuccess() template.
Add error checking to api.nim calls.
* Deprecated usage onceToAll() for better stability.
Address comment and send attestations asap.
* Avoid unnecessary loop when calculating minimal duration.
* Implement split preset/config support
This is the initial bulk refactor to introduce runtime config values in
a number of places, somewhat replacing the existing mechanism of loading
network metadata.
It still needs more work, this is the initial refactor that introduces
runtime configuration in some of the places that need it.
The PR changes the way presets and constants work, to match the spec. In
particular, a "preset" now refers to the compile-time configuration
while a "cfg" or "RuntimeConfig" is the dynamic part.
A single binary can support either mainnet or minimal, but not both.
Support for other presets has been removed completely (can be readded,
in case there's need).
There's a number of outstanding tasks:
* `SECONDS_PER_SLOT` still needs fixing
* loading custom runtime configs needs redoing
* checking constants against YAML file
* yeerongpilly support
`build/nimbus_beacon_node --network=yeerongpilly --discv5:no --log-level=DEBUG`
* load fork epoch from config
* fix fork digest sent in status
* nicer error string for request failures
* fix tools
* one more
* fixup
* fixup
* fixup
* use "standard" network definition folder in local testnet
Files are loaded from their standard locations, including genesis etc,
to conform to the format used in the `eth2-networks` repo.
* fix launch scripts, allow unknown config values
* fix base config of rest test
* cleanups
* bundle mainnet config using common loader
* fix spec links and names
* only include supported preset in binary
* drop yeerongpilly, add altair-devnet-0, support boot_enr.yaml
* Implement the new Altair req/resp protocols
Also fixes the altair message-id computation by providing the correct
forkdigest prefix in `isAltairTopic`.
Co-authored-by: Tanguy Cizain <tanguycizain@gmail.com>
* add blockchain_dag altair database reading; add rollback tests; fix some unnecessary type conversions
* remove debugging scaffolding
* proposeSignedBlock() will need to be async for merge; introduce altair types to VC
* add Altair support to the block quarantine
* switch some spec/datatypes imports to spec/datatypes/base
* add Altair support to block_clearance
* allow runtime configuration of Altair transition slot
* enable Altair in block_sim, including in CI
* use ForkedHashedBeaconState in StateData
* fix FAR_FUTURE_EPOCH -> slot overflow; almost always use assign()
* avoid stack allocation in maybeUpgradeStateToAltair()
* create and use dispatch functions for check_attester_slashing(), check_proposer_slashing(), and check_voluntary_exit()
* use getStateRoot() instead of various state.data.hbsPhase0.root
* remove withStateVars.hashedState(), which doesn't work as a design anymore
* introduce spec/datatypes/altair into beacon_chain_db
* fix inefficient codegen for getStateField(largeStateField)
* state_transition_slots() doesn't either need/use blocks or runtime presets
* combine process_slots(HBS)/state_transition_slots(HBS) which differ only in last-slot htr optimization
* getStateField(StateData, ...) was replaced by getStateField(ForkedHashedBeaconState, ...)
* fix rollback
* switch some state_transition(), process_slots, makeTestBlocks(), etc to use ForkedHashedBeaconState
* remove state_transition(phase0.HashedBeaconState)
* remove process_slots(phase0.HashedBeaconState)
* remove state_transition_block(phase0.HashedBeaconState)
* remove unused callWithBS(); separate case expression from if statement
* switch back from nested-ref-object construction to (ref Foo)(Bar())
* write uncompressed validator keys to database
Loading 150k+ validator keys on startup in compressed format takes a lot
of time - better store them in uncompressed format which makes behaviour
just after startup faster / more predictable.
* refactor cached validator key access
* fix isomorphic cast to work with non-var instances
* remove cooked pubkey cache - directly use database cache in chaindag
as well (one less cache to keep in sync)
* bump blscurve, introduce loadValid for known-to-be-valid keys
Instead of keeping a validator key list per EpochRef, this PR introduces
a single shared validator key list in ChainDAG, and cleans up some other
ChainDAG and key-related issues.
The PR does not introduce the validator key list in the state transition
- this is because we batch-check all signatures before entering the spec
code, thus the spec code never hits the cache.
A future refactor should _probably_ remove the threadvar altogether.
There's a few other small fixes in here that make the flow easier to
read:
* fix `var ChainDAGRef` -> `ChainDAGRef`
* fix `var QuarantineRef` -> `QuarantineRef`
* consistent `dag` variable name
* avoid using threadvar pubkey cache in most cases
* better error messages in batch signature checking
* use StateData in place of BeaconState outside state transition code
* propagate more StateData usage
* remove withStateVars().state
* wrap get_beacon_committee(BeaconState, ...) as gbc(StateData, ...)
* switch makeAttestation() to use StateData
* use StateData wrapper/dispatcher for get_committee_count_per_slot()
* convert AttestationCache.init(), weak subjectivity functions, and updateValidatorMetrics()
* add get_shuffled_active_validator_indices(StateData) and get_block_root_at_slot(StateData)
* switch makeAttestationData() to StateData
* sync AllTests-mainnet.md after rebase
This PR decreases the lead subscription time which should help
decrease bandwidth usage and CPU making the subscription for future
aggregation happen a bit later. There's room for more tuning here,
probably.
* fix missing negation from in #2550
* fix silly bitarray issues
* decrease subnet lead subscription time
* log all subnet switching source data
* rename subnet trackers to refer to stability and aggregate subnets
* more tests
Currently, we have a bit of a convoluted flow where when sending
attestations, we start broadcasting them over gossip then pass them to
the attestation validation to include them in the local attestation pool
- it should be the other way around: we should be checking attestations
_before_ gossipping them - this serves as an additional safety net to
ensure that we don't publish junk - this becomes more important when
publishing attestations from the API.
Also, the REST API was performing its own validation meaning
attestations coming from REST would be validated twice - finally, the
JSON RPC wasn't pre-validating and would happily broadcast invalid
attestations.
* Unified attestation production pipeline with the same flow for gossip,
locally and API-produced attestations: all are now validated and entered
into the pool, then broadcast/republished
* Refactor subnet handling with specific SubnetId alias, streamlining
where subnets are computed, avoiding the need to pass around the number
of active validators
* Move some of the subnet handling code to eth2_network
* Use BitArray throughout for subnet handling
* REST API test framework and tests.
* Fix ValidatorIndex tests to properly handle int32, but not uint32 values.
* Fix tests to follow latest REST fixes.
* refactor restapi.sh
and add it to the test suite
* Fix issues.
Add delay timeout which is required.
* Fix restapi.sh script for Windows.
Co-authored-by: Ștefan Talpalaru <stefantalpalaru@yahoo.com>
* set upper bound on EpochRef cache
* max 32 EpochRef instances
* less memory waste in BlockRef by removing EpochRef seq that is mostly
unused (~20mb)
* less memory waste in dag block lookup by not keeping an extra copy of
digest (~70mb)
* fix `==` and `$` for Eth2Digest
* remove `ChainDAG.tmpState` (~50mb?)
all in all, this branch cuts mainnet memory usage by ~160-180mb and puts
limits on EpochRef cache usage - where normally it hovered around 950mb
before, it's now sitting at 600-700mb on my machine.
* docs
* database state storage benchmarking via ncli_db
* more cleanups from immutable validator state branch
* unexport some eth2_network constants and remove unused variables/templates
* make two PeerScore constants public
* expose node signatures
* format bitseqs as hex strings
* format trusted sigs as hex strings (same as untrusted)
* reuse rpc client sigs
* include validator index in duties
* move SyncInfo to spec
* use IntSet rather than HashSet[ValidatorIndex]
* add bounds check before uint64 -> int conversion
* use intsets in block transitions
* remove superfluous Nim issue explanation/reference
* performance fixes
* don't mark tree cache as dirty on read-only List accesses
* store only blob in memory for keys and signatures, parse blob lazily
* compare public keys by blob instead of parsing / converting to raw
* compare Eth2Digest using non-constant-time comparison
* avoid some unnecessary validator copying
This branch will in particular speed up deposit processing which has
been slowing down block replay.
Pre (mainnet, 1600 blocks):
```
All time are ms
Average, StdDev, Min, Max, Samples, Test
Validation is turned off meaning that no BLS operations are performed
3450.269, 0.000, 3450.269, 3450.269, 1, Initialize DB
0.417, 0.822, 0.036, 21.098, 1400, Load block from database
16.521, 0.000, 16.521, 16.521, 1, Load state from database
27.906, 50.846, 8.104, 1507.633, 1350, Apply block
52.617, 37.029, 20.640, 135.938, 50, Apply epoch block
```
Post:
```
3502.715, 0.000, 3502.715, 3502.715, 1, Initialize DB
0.080, 0.560, 0.035, 21.015, 1400, Load block from database
17.595, 0.000, 17.595, 17.595, 1, Load state from database
15.706, 11.028, 8.300, 107.537, 1350, Apply block
33.217, 12.622, 17.331, 60.580, 50, Apply epoch block
```
* more perf fixes
* load EpochRef cache into StateCache more aggressively
* point out security concern with public key cache
* reuse proposer index from state when processing block
* avoid genericAssign in a few more places
* don't parse key when signature is unparseable
* fix `==` overload for Eth2Digest
* preallocate validator list when getting active validators
* speed up proposer index calculation a little bit
* reuse cache when replaying blocks in ncli_db
* avoid a few more copying loops
```
Average, StdDev, Min, Max, Samples, Test
Validation is turned off meaning that no BLS operations are performed
3279.158, 0.000, 3279.158, 3279.158, 1, Initialize DB
0.072, 0.357, 0.035, 13.400, 1400, Load block from database
17.295, 0.000, 17.295, 17.295, 1, Load state from database
5.918, 9.896, 0.198, 98.028, 1350, Apply block
15.888, 10.951, 7.902, 39.535, 50, Apply epoch block
0.000, 0.000, 0.000, 0.000, 0, Database block store
```
* clear full balance cache before processing rewards and penalties
```
All time are ms
Average, StdDev, Min, Max, Samples, Test
Validation is turned off meaning that no BLS operations are performed
3947.901, 0.000, 3947.901, 3947.901, 1, Initialize DB
0.124, 0.506, 0.026, 202.370, 363345, Load block from database
97.614, 0.000, 97.614, 97.614, 1, Load state from database
0.186, 0.188, 0.012, 99.561, 357262, Advance slot, non-epoch
14.161, 5.966, 1.099, 395.511, 11524, Advance slot, epoch
1.372, 4.170, 0.017, 276.401, 363345, Apply block, no slot processing
0.000, 0.000, 0.000, 0.000, 0, Database block store
```
* remove await/async from sub/unsub
* fix unsubscribe wrong key (missed _snappy)
* use the right libp2p commit hash
* remove unused async
* fix inspector
* fix subnet calculation in RPC and insert broadcast attestations into node's pool
* unify codepaths to ensure only mostly-checked-to-be-valid attestations enter the pool, even from node's own broadcasts
* update attestation pool tests for new validateAttestation param
Co-authored-by: Dustin Brody <tersec@users.noreply.github.com>
* fix subnet calculation in RPC and insert broadcast attestations into node's pool
* unify codepaths to ensure only mostly-checked-to-be-valid attestations enter the pool, even from node's own broadcasts
* update attestation pool tests for new validateAttestation param
* make subnet cycling more robust; use one stability subnet/validator; explicitly represent gossip enabled/disabled
* fix asymmetry in _snappy being used for subscriptions but not unsubscriptions
* remove redundant comment
* minimal RPC and VC support for infoming BN of subnets
* create and verify slot signatures in RPC interface and VC
* loosen old slot check
* because Slot + uint64 works but uint64 + Slot doesn't
* document assumptions for head state use; don't clear stability subnets; guard against VC not having checked an epoch ahead, fixing a crash; clarify unsigned comparison
* revert unsub fix
* Revert "Revert "Full "node" RPC calls implementation and fixes to peer lifetime states. (#2065)" (#2082)"
This reverts commit 7cc3dc8027.
* fix nil disconnectedFut crash
* fixes
don't resetPeer, it causes peer miscounts
* disconnect disconnecting peers
...when there's a race.
* avoid connection spamming
* never decrease SeenTable timeout
* only recover ENR for known peers
* seen only when really disconnected