We select a peer to ask a block randomly. Peer's send channel has
capacity 10. If we need too many blocks we limit number of blocks to asks as a number of peers
* 10, which means that there is some probability (pretty high) that we
will overflow send buffer capacity.
This fix freezes a peer list (which gives also some performance boost)
and create a cycle iteraror to equally distribute requests among the
peers.
There is a risk that a peer may be disconnected while we are sending a
request to the chanel, but stricltly speaking it was possible in the old
code too, perhaps with a lower probability.
Fixes#1748
* header MMR in use within txhashset itself
works with fast sync
not yet in place for initial header sync
* add the (currently unused) sync_head mmr
* use sync MMR during fast sync
rebuild header MMR after we validate full txhashset after download
* support missing header MMR (rebuild as necessary) for legacy nodes
* rename to HashOnly
* cleanup backend.append()
* simplify vec_backend to match simpler append api
* header MMR in use within txhashset itself
works with fast sync
not yet in place for initial header sync
* add the (currently unused) sync_head mmr
* use sync MMR during fast sync
rebuild header MMR after we validate full txhashset after download
* support missing header MMR (rebuild as necessary) for legacy nodes
* rustfmt
* comments/docs
* rustfmt
* cleanup DBBackend
* cleanup DBBackend
* cleanup
* rename to HashOnly
* rustfmt
* cleanup backend.append()
* simply pmmr append api
no need to pass position when appending
* cleanup
* simplify vec_backend to match simpler append api
* rustfmt
* docs/comments
* rustfmt
* cleanup
* Use secp crate directly without extra use statement (#1738)
(cherry picked from commit 80d28f94ea)
* suppress the test error of test_start_api. Note: this is not a fix.
(cherry picked from commit 6f29685daf)
* First pass at secondary proof of work difficulty adjustments
* Core and chain test fixes
* Next difficulty calc now needs a height. Scaling calculation fixes. Setting scaling on mined block.
* Change factor to u32 instead of u64.
* Cleanup structs used by next_difficulty
* Fix header size calc with u32 scaling
* fix: avoid a confusing log when fastsync start (#1720)
(cherry picked from commit 4f462cdfdc)
* small speed optimization for header sync (#1719)
(cherry picked from commit d3589d1bf5)
