* Simplify accounts healing threshold management
why:
Was over-engineered.
details:
Previously, healing was based on recursive hexary trie perusal.
Due to "cheap" envelope decomposition of a range complement for the
hexary trie, the cost of running extra laps have become time-affordable
again and a simple trigger mechanism for healing will do.
* Control number of dangling result nodes in `hexaryInspectTrie()`
also:
+ Returns number of visited nodes available for logging so the maximum
number of nodes can be tuned accordingly.
+ Some code and docu update
* Update names of constants
why:
Declutter, more systematic naming
* Re-implemented `worker_desc.merge()` for storage slots
why:
Provided as proper queue management in `storage_queue_helper`.
details:
+ Several append modes (replaces `merge()`)
+ Added third queue to record entries currently fetched by a worker. So
another parallel running worker can safe the complete set of storage
slots in as checkpoint. This was previously lost.
* Refactor healing
why:
Simplify and remove deep hexary trie perusal for finding completeness.
Due to "cheap" envelope decomposition of a range complement for the
hexary trie, the cost of running extra laps have become time-affordable
again and a simple trigger mechanism for healing will do.
* Docu update
* Run a storage job only once in download loop
why:
Download failure or rejection (i.e. missing data) lead to repeated
fetch requests until peer disconnects, otherwise.
* Update docu and logging
* Extracted and updated constants from `worker_desc` into separate file
* Update and re-calibrate communication error handling
* Allow simplified pivot negotiation
why:
This feature allows to turn off pivot negotiation so that peers agree
on a a pivot header.
For snap sync with fast changing pivots this only throttles the sync
process. The finally downloaded DB snapshot is typically a merged
version of different pivot states augmented by a healing process.
* Re-model worker queues for accounts download & healing
why:
Currently there is only one data fetch per download or healing task.
This task is then repeated by the scheduler after a short time. In
many cases, this short time seems enough for some peers to decide to
terminate connection.
* Update main task batch `runMulti()`
details:
The function `runMulti()` is activated in quasi-parallel mode by the
scheduler. This function calls the download, healing and fast-sync
functions.
While in debug mode, after each set of jobs run by this function the
database is analysed (by the `snapdb_check` module) and the result
printed.
* Re-arrange fetching storage slots in batch module
why;
Previously, fetching partial slot ranges first has a chance of
terminating the worker peer 9due to network error) while there were
many inheritable storage slots on the queue.
Now, inheritance is checked first, then full slot ranges and finally
partial ranges.
* Update logging
* Bundled node information for healing into single object `NodeSpecs`
why:
Previously, partial paths and node keys were kept in separate variables.
This approach was error prone due to copying/reassembling function
argument objects.
As all partial paths, keys, and node data types are more or less handled
as `Blob`s over the network (using Eth/6x, or Snap/1) it makes sense to
hold these `Blob`s as named field in a single object (even if not all
fields are active for the current purpose.)
* For good housekeeping, using `NodeKey` type only for account keys
why:
previously, a mixture of `NodeKey` and `Hash256` was used. Now, only
state or storage root keys use the `Hash256` type.
* Always accept latest pivot (and not a slightly older one)
why;
For testing it was tried to use a slightly older pivot state root than
available. Some anecdotal tests seemed to suggest an advantage so that
more peers are willing to serve on that older pivot. But this could not
be confirmed in subsequent tests (still anecdotal, though.)
As a side note, the distance of the latest pivot to its predecessor is
at least 128 (or whatever the constant `minPivotBlockDistance` is
assigned to.)
* Reshuffle name components for some file and function names
why:
Clarifies purpose:
"storages" becomes: "storage slots"
"store" becomes: "range fetch"
* Stash away currently unused modules in sub-folder named "notused"
* Re-model persistent database access
why:
Storage slots healing just run on the wrong sub-trie (i.e. the wrong
key mapping). So get/put and bulk functions now use the definitions
in `snapdb_desc` (earlier there were some shortcuts for `get()`.)
* Fixes: missing return code, typo, redundant imports etc.
* Remove obsolete debugging directives from `worker_desc` module
* Correct failing unit tests for storage slots trie inspection
why:
Some pathological cases for the extended tests do not produce any
hexary trie data. This is rightly detected by the trie inspection
and the result checks needed to adjusted.
* Split fetch accounts into sub-modules
details:
There will be separated modules for accounts snapshot, storage snapshot,
and healing for either.
* Allow to rebase pivot before negotiated header
why:
Peers seem to have not too many snapshots available. By setting back the
pivot block header slightly, the chances might be higher to find more
peers to serve this pivot. Experiment on mainnet showed that setting back
too much (tested with 1024), the chances to find matching snapshot peers
seem to decrease.
* Add accounts healing
* Update variable/field naming in `worker_desc` for readability
* Handle leaf nodes in accounts healing
why:
There is no need to fetch accounts when they had been added by the
healing process. On the flip side, these accounts must be checked for
storage data and the batch queue updated, accordingly.
* Reorganising accounts hash ranges batch queue
why:
The aim is to formally cover as many accounts as possible for different
pivot state root environments. Formerly, this was tried by starting the
accounts batch queue at a random value for each pivot (and wrapping
around.)
Now, each pivot environment starts with an interval set mutually
disjunct from any interval set retrieved with other pivot state roots.
also:
Stop fishing for more pivots in `worker` if 100% download is reached
* Reorganise/update accounts healing
why:
Error handling was wrong and the (math. complexity of) whole process
could be better managed.
details:
Much of the algorithm is now documented at the top of the file
`heal_accounts.nim`
* Added inspect module
why:
Find dangling references for trie healing support.
details:
+ This patch set provides only the inspect module and some unit tests.
+ There are also extensive unit tests which need bulk data from the
`nimbus-eth1-blob` module.
* Alternative pivot finder
why:
Attempt to be faster on start up. Also tying to decouple pivot finder
somehow by providing different mechanisms (this one runs in `single`
mode.)
* Use inspect module for healing
details:
+ After some progress with account and storage data, the inspect facility
is used to find dangling links in the database to be filled nose-wise.
+ This is a crude attempt to cobble together functional elements. The
set up needs to be honed.
* fix scheduler to avoid starting dead peers
why:
Some peers drop out while in `sleepAsync()`. So extra `if` clauses
make sure that this event is detected early.
* Bug fixes causing crashes
details:
+ prettify.toPC():
int/intToStr() numeric range over/underflow
+ hexary_inspect.hexaryInspectPath():
take care of half initialised step with branch but missing index into
branch array
* improve handling of dropped peers in alternaive pivot finder
why:
Strange things may happen while querying data from the network.
Additional checks make sure that the state of other peers is updated
immediately.
* Update trace messages
* reorganise snap fetch & store schedule
Jordan Hrycaj