67b7fecacd [mempool] clear mapDeltas entry if prioritisetransaction sets delta to 0 (glozow)
c1061acb9d [functional test] prioritisation is not removed during replacement and expiry (glozow)
0e5874f0b0 [functional test] getprioritisedtransactions RPC (glozow)
99f8046829 [rpc] add getprioritisedtransactions (glozow)
9e9ca36c80 [mempool] add GetPrioritisedTransactions (glozow)
Pull request description:
Add an RPC to get prioritised transactions (also tells you whether the tx is in mempool or not), helping users clean up `mapDeltas` manually. When `CTxMemPool::PrioritiseTransaction` sets a delta to 0, remove the entry from `mapDeltas`.
Motivation / Background
- `mapDeltas` entries are never removed from mapDeltas except when the tx is mined in a block or conflicted.
- Mostly it is a feature to allow `prioritisetransaction` for a tx that isn't in the mempool {yet, anymore}. A user can may resbumit a tx and it retains its priority, or mark a tx as "definitely accept" before it is seen.
- Since #8448, `mapDeltas` is persisted to mempool.dat and loaded on restart. This is also good, otherwise we lose prioritisation on restart.
- Note the removal due to block/conflict is only done when `removeForBlock` is called, i.e. when the block is received. If you load a mempool.dat containing `mapDeltas` with transactions that were mined already (e.g. the file was saved prior to the last few blocks), you don't delete them.
- Related: #4818 and #6464.
- There is no way to query the node for not-in-mempool `mapDeltas`. If you add a priority and forget what the value was, the only way to get that information is to inspect mempool.dat.
- Calling `prioritisetransaction` with an inverse value does not remove it from `mapDeltas`, it just sets the value to 0. It disappears on a restart (`LoadMempool` checks if delta is 0), but that might not happen for a while.
Added together, if a user calls `prioritisetransaction` very regularly and not all those transactions get mined/conflicted, `mapDeltas` might keep lots of entries of delta=0 around. A user should clean up the not-in-mempool prioritisations, but that's currently difficult without keeping track of what those txids/amounts are.
ACKs for top commit:
achow101:
ACK 67b7fecacd
theStack:
Code-review ACK 67b7fecacd
instagibbs:
code review ACK 67b7fecacd
ajtowns:
ACK 67b7fecacd code review only, some nits
Tree-SHA512: 9df48b622ef27f33db1a2748f682bb3f16abe8172fcb7ac3c1a3e1654121ffb9b31aeaad5570c4162261f7e2ff5b5912ddc61a1b8beac0e9f346a86f5952260a
1af72e728d