Previously we would sanity check the -maxmempool configuration based on a
multiple of the descendant size limit, but with cluster mempool the maximum
evicted size is now the cluster size limit, so use that instead.
Also allow -maxmempool=0 in general (and not just if
-limitdescendantsize/-limitclustersize is set to 0).
We use CompareMiningScoreWithTopology() for sorting transaction announcements
during tx relay, and we use GetSortedScoreWithTopology() in
CTxMemPool::check().
Calculating mempool ancestors for a new transaction should not be done until
after cluster size limits have been enforced, to limit CPU DoS potential.
Achieve this by reworking TRUC and RBF validation logic:
- TRUC policy enforcement is now done using only mempool parents of
new transactions, not all mempool ancestors (note that it's fine to calculate
ancestors of in-mempool transactions, if the number of such calls is
reasonably bounded).
- RBF replacement checks are performed earlier (which allows for checking
cluster size limits earlier, because cluster size checks cannot happen until
after all conflicts are staged for removal).
- Verifying that a new transaction doesn't conflict with an ancestor now
happens later, in AcceptSingleTransaction() rather than in PreChecks(). This
means that the test is not performed at all in AcceptMultipleTransactions(),
but in package acceptance we already disallow RBF in situations where a
package transaction has in-mempool parents.
Also to ensure that all RBF validation logic is applied in both the single
transaction and multiple transaction cases, remove the optimization that skips
the PackageMempoolChecks() in the case of a single transaction being validated
in AcceptMultipleTransactions().
Now that ancestor calculation never fails (due to ancestor/descendant limits
being eliminated), we can eliminate the error handling from
CalculateMemPoolAncestors.
With the descendant size limits removed, replace the concept of "max number of
descendants of any ancestor of a given tx" with the cluster count of the cluster
that the transaction belongs to.
The mempool clusters and linearization permit sorting the mempool topologically
without making use of ancestor counts (as long as the graph is not oversized).
Co-authored-by: Pieter Wuille <pieter@wuille.net>
Previously, transaction batches were first sorted by ancestor count and then
feerate, to ensure transactions are announced in a topologically valid order,
while prioritizing higher feerate transactions. Ancestor count is a crude
topological sort criteria, so replace this with linearization order so that the
highest feerate transactions (as would be observed by the mining algorithm) are
relayed before lower feerate ones, in a topologically valid way.
This also fixes a test that only worked due to the ancestor-count-based sort
order.
With a total ordering on mempool transactions, we are now able to calculate a
transaction's mining score at all times. Use this to improve the RBF logic:
- we no longer enforce a "no new unconfirmed parents" rule
- we now require that the mempool's feerate diagram must improve in order
to accept a replacement
- the topology restrictions for conflicts in the package rbf setting have been
eliminated
Revert the temporary change to mempool_ephemeral_dust.py that were previously
made due to RBF validation checks being reordered.
Co-authored-by: Gregory Sanders <gsanders87@gmail.com>, glozow <gloriajzhao@gmail.com>
Rather than evicting the transactions with the lowest descendant feerate,
instead evict transactions that have the lowest chunk feerate.
Once mining is implemented based on choosing transactions with highest chunk
feerate (see next commit), mining and eviction will be opposites, so that we
will evict the transactions that would be mined last.
Include an adjustment to mempool_tests.cpp due to the additional memory used by
txgraph.
Includes a temporary change to the mempool_ephemeral_dust.py functional test,
due to validation checks being reordered. This change will revert once the RBF
rules are changed in a later commit.
Simplifies `m_tx_inventory_to_send` a bit by making it a set of Wtxids.
Wtxid relay is prevalent throughout the network, so the complexity of
dealing with a GenTxid in this data structure isn't necessary.
For peers that aren't wtxid relay, the txid is now retrieved from our
mempool entry when the inv is constructed.
During Initial Block Download, the mempool is usually empty, but `CTxMemPool::removeForBlock` is still called for every connected block where we:
* iterate over every transaction in the block even though none will be found in the empty `mapTx`, always leaving `txs_removed_for_block` empty...
* which is pre-allocated regardless with 40 bytes * vtx.size(), even though it will always remain empty.
This change introduces a minor performance optimization by only executing the loop if any of the core mempool maps have any contents.
The call to `MempoolTransactionsRemovedForBlock` and the updates to the rolling fee logic remain unchanged.
The `removeForBlock` was also updated stylistically to match the surrounding methods and a clarification was added to clarify that it affects fee estimation as well.
a60f863d3e276534444571282f432b913d3967db scripted-diff: Replace GenTxidVariant with GenTxid (marcofleon)
c8ba1995986323cd9e76097acc1f15eed7c60943 Remove old GenTxid class (marcofleon)
072a198ea4bc9f1e8449cd31e55d397b75ce4ad5 Convert remaining instances of GenTxid to GenTxidVariant (marcofleon)
1b528391c79497ae19f7e481439e350533c7cd1a Convert `txrequest` to GenTxidVariant (marcofleon)
bde4579b0780aa3754af35beffbcfeb31f28045b Convert `txdownloadman_impl` to GenTxidVariant (marcofleon)
c876a892ec0b04851bea0a688d7681b6aaca4cb7 Replace GenTxid with Txid/Wtxid overloads in `txmempool` (marcofleon)
de858ce2bea83c53635dee9a49c8c273a12440dd move-only: make GetInfo a private CTxMemPool member (stickies-v)
eee473d9f3019a0ea4ebbc9c41781813ad574a86 Convert `CompareInvMempoolOrder` to GenTxidVariant (marcofleon)
243553d59071f3e43a42f3809706790495b17ffc refactor: replace get_iter_from_wtxid with GetIter(const Wtxid&) (stickies-v)
fcf92fd640eae60d1f601136a4e1c9de8ccb68b5 refactor: make CTxMemPool::GetIter strongly typed (marcofleon)
11d28f21bb8f0c3094934b3fef45871f73bb216a Implement GenTxid as a variant (marcofleon)
Pull request description:
Part of the [type safety refactor](https://github.com/bitcoin/bitcoin/pull/32189).
This PR changes the GenTxid class to a variant, which holds both Txids and Wtxids. This provides compile-time type safety and eliminates the manual type check (bool m_is_wtxid). Variables that can be either a Txid or a Wtxid are now using the new GenTxid variant, instead of uint256.
ACKs for top commit:
w0xlt:
ACK a60f863d3e
dergoegge:
Code review ACK a60f863d3e276534444571282f432b913d3967db
maflcko:
review ACK a60f863d3e276534444571282f432b913d3967db 🎽
theStack:
Code-review ACK a60f863d3e276534444571282f432b913d3967db
Tree-SHA512: da9b73b7bdffee2eb9281a409205519ac330d3336094d17681896703fbca8099608782c9c85801e388e4d90af5af8abf1f34931f57bbbe6e9674d802d6066047
Now that we are storing `CTxMemPool::CompareDepthAndScore` parameters using
`std::variant` we have no portable zero-overhead way of accessing them,
so use `std::visit` and drop `bool wtxid` in-parameter.
Co-authored-by: stickies-v <stickies-v@protonmail.com>
