New RPC methods: return an estimate of the fee (or priority) a
transaction needs to be likely to confirm in a given number of
blocks.
Mike Hearn created the first version of this method for estimating fees.
It works as follows:
For transactions that took 1 to N (I picked N=25) blocks to confirm,
keep N buckets with at most 100 entries in each recording the
fees-per-kilobyte paid by those transactions.
(separate buckets are kept for transactions that confirmed because
they are high-priority)
The buckets are filled as blocks are found, and are saved/restored
in a new fee_estiamtes.dat file in the data directory.
A few variations on Mike's initial scheme:
To estimate the fee needed for a transaction to confirm in X buckets,
all of the samples in all of the buckets are used and a median of
all of the data is used to make the estimate. For example, imagine
25 buckets each containing the full 100 entries. Those 2,500 samples
are sorted, and the estimate of the fee needed to confirm in the very
next block is the 50'th-highest-fee-entry in that sorted list; the
estimate of the fee needed to confirm in the next two blocks is the
150'th-highest-fee-entry, etc.
That algorithm has the nice property that estimates of how much fee
you need to pay to get confirmed in block N will always be greater
than or equal to the estimate for block N+1. It would clearly be wrong
to say "pay 11 uBTC and you'll get confirmed in 3 blocks, but pay
12 uBTC and it will take LONGER".
A single block will not contribute more than 10 entries to any one
bucket, so a single miner and a large block cannot overwhelm
the estimates.
Generally useless information. Only updates on connect time, not after
that. Peers can easily lie and the median filter is not effective in
preventing that.
In the past it was used for progress display in the GUI but
`CheckPoints::guessVerificationProgress` provides a better way that is now used.
It was too easy to mislead it. Peers do lie about it in practice, see issue #4065.
From the RPC, `getpeerinfo` gives the peer raw values, which are more
useful.
- introduce DEFAULT_SCRIPTCHECK_THREADS in main.h
- only show values from -"MAX_HW_THREADS" up to 16 for -par, as it
makes no sense to try to leave more "cores free" than the system
supports anyway
- use the new constant in optionsdialog and remove defaults from
.ui file
This resolves a case in which a mismatch could be used to bloat up the
mempool by sending transactions that pay enough fee to relay, but not
to be mined, with the default policies.
Extend CMerkleTx::GetDepthInMainChain with the concept of
a "conflicted" transaction-- a transaction generated by the wallet
that is not in the main chain or in the mempool, and, therefore,
will likely never be confirmed.
GetDepthInMainChain() now returns -1 for conflicted transactions
(0 for unconfirmed-but-in-the-mempool, and >1 for confirmed).
This makes getbalance, getbalance '*', and listunspent all agree when there are
mutated transactions in the wallet.
Before:
listunspent: one 49BTC output
getbalance: 96 BTC (change counted twice)
getbalance '*': 46 BTC (spends counted twice)
After: all agree, 49 BTC available to spend.
contrib/devtools/fix-copyright-headers.py script to be able to perform this maintenance task with ease during the rest of the year, every year. Modifications to contrib/devtools/README.md to document what fix-copyright-headers.py does.
Keep track of which block is being requested (and to be requested) from
each peer, and limit the number of blocks in-flight per peer. In addition,
detect stalled downloads, and disconnect if they persist for too long.
This means blocks are never requested twice, and should eliminate duplicate
downloads during synchronization.
In case the total number of orphan blocks in memory exceeds a limit
(currently set to 750), a random orphan block (which is not
depended on by another orphan block) is dropped. This means it will
need to be downloaded again, but it won't consume memory until then.
This changes the block processing logic from "try to atomically switch
to a new block" to a continuous "(dis)connect a block, aiming for the
assumed best chain".
This means the smallest atomic operations on the chainstate become
individual block connections or disconnections, instead of entire
reorganizations. It may mean that we try to reorganize to one block,
fail, and rereorganize again to the old block. This is slower, but
doesn't require unbounded RAM.
It also means that a ConnectBlock which fails may be no longer called
from the ProcessBlock which knows which node sent it. To deal with that,
a mapBlockSource is kept, and invalid blocks cause asynchronous "reject"
messages and banning (if necessary).
After discussing with BlueMatt, this appears to be harmless in its
current state since it's always set before it's used. Initialize it
anyway for readability and future safety.
Use misc methods of avoiding unnecesary header includes.
Replace int typedefs with int##_t from stdint.h.
Replace PRI64[xdu] with PRI[xdu]64 from inttypes.h.
Normalize QT_VERSION ifs where possible.
Resolve some indirect dependencies as direct ones.
Remove extern declarations from .cpp files.
As block index entries have a flag for marking invalid blocks, the
'best invalid work' information can be derived from there. In addition,
remove the global from main.h
This removes a few unused CBlockLocator methods, and moves the
construction and fork-finding logic to CChain (which can do these
more efficiently, as it has a height-indexable chain available).
It also makes CBlockLocator independent from the validation code.
Pieter Wuille