70db324663
This modifies the way orphan removal and processing is done to more
aggressively remove orphans that can no longer be valid due to other
transactions being added or removed from the primary transaction pool.
The net effect of these changes is that orphan pool will typically be
much smaller which greatly improves its effectiveness. Previously, it
would typically quickly reach the max allowed worst-case usage and
effectively stay there forever.
The following is a summary of the changes:
- Modify the map that tracks which orphans redeem a given transaction to
instead track by the specific outpoints that are redeemed
- Modify the various orphan removal and processing functions to accept
the full transaction rather than just its hash
- Introduce a new flag on removeOrphans which specifies whether or not
to remove the transactions that redeem the orphan being removed as
well which is necessary since only some paths require it
- Add a new function named removeOrphanDoubleSpends that is invoked
whenever a transaction is added to the main pool and thus the outputs
they spent become concrete spends
- Introduce a new flag on maybeAcceptTransaction which specifies whether
or not duplicate orphans should be rejected since only some paths
require it
- Modify processOrphans as follows:
- Make use of the modified map
- Use newly available flags and logic work more strictly work with tx
chains
- Recursively remove any orphans that also redeem any outputs redeemed
by the accepted transactions
- Several new tests to ensure proper functionality
- Removing an orphan that doesn't exist is removed both when there is
another orphan that redeems it and when there is not
- Removing orphans works properly with orphan chains per the new
remove redeemers flag
- Removal of multi-input orphans that double spend an output when a
concrete redeemer enters the transaction pool
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||
|---|---|---|
| .. | ||
| doc.go | ||
| error.go | ||
| log.go | ||
| mempool.go | ||
| mempool_test.go | ||
| policy.go | ||
| policy_test.go | ||
| README.md | ||
mempool
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(https://travis-ci.org/btcsuite/btcd) ![ISC License]
(http://img.shields.io/badge/license-ISC-blue.svg)
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(http://godoc.org/github.com/btcsuite/btcd/mempool)
Package mempool provides a policy-enforced pool of unmined bitcoin transactions.
A key responsbility of the bitcoin network is mining user-generated 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.
One of the policy configuration options controls whether or not "standard" transactions are accepted. In essence, a "standard" transaction is one that satisfies a fairly strict set of requirements that are largley intended to help provide fair use of the system to all users. It is important to note that what is considered a "standard" transaction changes over time. 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 bitcoin 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 bitcoin 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
- 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/btcsuite/btcd/mempool
License
Package mempool is licensed under the copyfree ISC License.