b6c088dc0d
This removes a redundant check for validating that votes and revocations are not in a block before they are allowed from CheckTransactionInputs since it has nothing to do with validation of transaction inputs and it's an impossible condition to hit in the block validation path because the same check is done much earlier in the validation process. It should also be noted that the checks this removes are also more permissive than they need to be because the first vote is not allowed until stake validation height, which is after stake enabled height. There is no effect on consensus because, as previously mentioned, the more restrictive checks earlier in the process prevent these checks from ever being exercised. However, the mempool previously relied on this duplicate check to reject early votes and revocations, so this adds the checks, with the corrected heights, directly to the mempool early in the process where they more naturally belong. It is more efficient to reject the transactions in that scenario earlier before doing more work as well. |
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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.