The state service API says explicitly that AwaitUTXO requests should be coupled
with a timeout layer. I didn't add this when I was testing and fixing the UTXO
lookup code (#1348, #1358) because causing zebrad to hang on a failed
dependency was useful for identifying cases where the code wasn't useful (and
then inspecting execution traces).
As a side effect, this ticket resolves most of the hangs in #1389, because
far-future gossiped blocks will have their UTXO lookups time out, though we
may wish to do other work as part of debugging the combined sync+gossip logic.
* Difficulty Contextual RFC: Introduction
Add a header, summary, and motivation
* Difficulty RFC: Add draft definitions
And update the state RFC definitions to match.
* Difficulty RFC: Add relevant chain
* Difficulty RFC: draft guide-level explanation
Outline the core calculations and checks.
* Difficulty RFC: Revised based on spec fixes
Update the design based on the spec bugs in #1276, #1277, and
zcash/zips#416.
These changes make the difficulty filter into a context-free check,
so we remove it from this contextual validation RFC.
* Difficulty RFC: Explain how Zebra's calculations can match the spec
* Difficulty RFC: write most of the reference section
Includes most of the implementation, modules for each function, and
draft notes for some of the remaining parts of the RFC.
* Difficulty RFC: Add an AdjustedDifficulty struct
* Difficulty RFC: Summarise module structure in the one place
* Difficulty RFC: Create implementation notes subsections
* Difficulty RFC: add consensus critical order of operations
* Difficulty RFC: Use the ValidateContextError type
* Difficulty RFC: make the median_time arg mut owned
We have to clone the data to pass a fixed-length array to a function,
so we might as well sort that array to find the median, and avoid a
copy.
Temporary fix so that Zebra's default logs support a typical workflow:
1. Developer or user runs Zebra with the default config
2. They send the logs to a terminal
3. When they see a bug, they copy-paste the last few log lines into a
bug report
This is the same change that was merged in #1373 and reverted in #1375.
We'll create a consistent logging design for Zebra in ticket #1381.
* Make debug_stop_at_height and ephemeral work together
* if `debug_stop_at_height` and `ephemeral` are set, delete the database
files after reaching the stop height
* drop or flush the database before `debug_stop_at_height` exits Zebra
Closes#1183.
The peer set maintains a preselected ready service that it can use to
perform power-of-two-choices (p2c) routing of requests. Ready services
are stored by key (socket address) in an `IndexMap`, and the preselected
service is represented by an `Option<usize>` indexing that map. This
means that whenever the set of ready services changes (e.g., a service
is removed from the peer set, or a service is taken to be used to
process a request), the preselected index is invalidated. The original
P2C-only implementation maintained this invariant but did not document
it.
The change to inventory-based routing introduced a bug by failing to
maintain this invariant and appropriately invalidate the preselected
index. However, this was only noticeable approximately 1/N of the time
on the next request after an inventory-directed request, so the bug
occurred infrequently. Luckily, the use of `.expect` caused the bug to
be an immediate panic, making it possible to identify by inspecting all
uses of the ready service map.