f81e19783c
This implements the agenda for voting on the sequence lock fixes as
defined in DCP0004 along with consensus tests and mempool acceptance
tests to ensure its correctness.
It also modifies the mempool to conditionally treat all transactions
with enabled sequence locks as non standard until the vote passes at
which point the will become standard with the modified semantics
enforced.
The following is an overview of the changes:
- Generate new version blocks and reject old version blocks after a
super majority has been reached
- New block version on mainnet is version 6
- New block version on testnet is version 7
- Introduce a convenience function for determining if the vote passed
and is now active
- Enforce modified sequence lock semantics in accordance with the state
of the vote
- Modify the more strict standardness checks (acceptance to the mempool
and relay) to enforce DCP0004 in accordance with the state of the vote
- Make all transactions with enabled sequence locks non standard until
the agenda vote passes
- Add tests to ensure acceptance and relay behave according to the
aforementioned description
- Add tests for determining if the agenda is active for both mainnet and
testnet
- Add tests to ensure the corrected sequence locks are handled properly
depending on the result of the vote
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|---|---|---|
| .. | ||
| doc.go | ||
| error.go | ||
| go.mod | ||
| go.sum | ||
| log.go | ||
| mempool_test.go | ||
| mempool.go | ||
| policy_test.go | ||
| policy.go | ||
| README.md | ||
mempool
Package mempool provides a policy-enforced pool of unmined Decred transactions.
A key responsibility of the Decred network is mining transactions – regular transactions and stake transactions – into blocks. In order to facilitate this, the mining process relies on having a readily-available source of transactions to include in a block that is being solved.
At a high level, this package satisfies that requirement by providing an in-memory pool of fully validated transactions that can also optionally be further filtered based upon a configurable policy.
The Policy configuration options has flags that control whether or not "standard" transactions and old votes are accepted into the mempool. In essence, a "standard" transaction is one that satisfies a fairly strict set of requirements that are largely intended to help provide fair use of the system to all users. It is important to note that what is considered to be a "standard" transaction changes over time as policy and consensus rules evolve. For some insight, at the time of this writing, an example of some of the criteria that are required for a transaction to be considered standard are that it is of the most-recently supported version, finalized, does not exceed a specific size, and only consists of specific script forms.
Since this package does not deal with other Decred specifics such as network communication and transaction relay, it returns a list of transactions that were accepted which gives the caller a high level of flexibility in how they want to proceed. Typically, this will involve things such as relaying the transactions to other peers on the network and notifying the mining process that new transactions are available.
This package has intentionally been designed so it can be used as a standalone package for any projects needing the ability create an in-memory pool of Decred transactions that are not only valid by consensus rules, but also adhere to a configurable policy
Feature Overview
The following is a quick overview of the major features. It is not intended to be an exhaustive list.
- Maintain a pool of fully validated transactions
- Reject non-fully-spent duplicate transactions
- Reject coinbase transactions
- Reject double spends (both from the chain and other transactions in pool)
- Reject invalid transactions according to the network consensus rules
- Full script execution and validation with signature cache support
- Individual transaction query support
- Stake transaction support (ticket purchases, votes and revocations)
- Option to accept or reject old votes
- Orphan transaction support (transactions that spend from unknown outputs)
- Configurable limits (see transaction acceptance policy)
- Automatic addition of orphan transactions that are no longer orphans as new transactions are added to the pool
- Individual orphan transaction query support
- Configurable transaction acceptance policy
- Option to accept or reject standard transactions
- Option to accept or reject transactions based on priority calculations
- Rate limiting of low-fee and free transactions
- Non-zero fee threshold
- Max signature operations per transaction
- Max orphan transaction size
- Max number of orphan transactions allowed
- Additional metadata tracking for each transaction
- Timestamp when the transaction was added to the pool
- Most recent block height when the transaction was added to the pool
- The fee the transaction pays
- The starting priority for the transaction
- Manual control of transaction removal
- Recursive removal of all dependent transactions
Installation and Updating
$ go get -u github.com/decred/dcrd/mempool
License
Package mempool is licensed under the copyfree ISC License.