crds table retains up to 32 node-instance values per each pubkey. This
is so because if there are multiple running instances of the same node,
then we want gossip to propagate node-instance values associated with
both instances, therefore the corresponding label/key includes the
randomly generated token in addition to the pubkey:
https://github.com/solana-labs/solana/blob/9c42a89a4/core/src/crds_value.rs#L448https://github.com/solana-labs/solana/pull/14037
As a result, the number of such values per pubkey are effectively
unbounded, requiring custom mitigations implemented in:
https://github.com/solana-labs/solana/pull/14467
but still taking redundant extra memory and bandwidth.
This commit instead retains only one node-instance per pubkey by
extending crds values override logic. If a crds value is of type
node-instance, it will always override an existing one with the same key
if it has more recent starting timestamp (not wallclock). As a result,
gossip will always propagate the node-instance with more recent
timestamp. Since the check_duplicate logic will stop the node with older
timestamp, this change should preserve existing functionality.
* purge_old_snapshot_archives is changed to take an extra argument 'maximum_snapshots_to_retain' to control the max number of latest snapshot archives to retain. Note the oldest snapshot is always retained as before and is not subjected to this new options.
* The validator and ledger-tool executables are modified with a CLI argument --maximum-snapshots-to-retain. And the options are propagated down the call chains. Their corresponding shell scripts were changed accordingly.
* SnapshotConfig is modified to have an extra field for the maximum_snapshots_to_retain
* Unit tests are developed to cover purge_old_snapshot_archives
* Require that blockstore block-time only be recognized slot, instead of root
* Move cache_block_time to after Bank freeze
* Single use statement
* Pass transaction_status_sender by reference
* Remove unnecessary slot-existence check before caching block time altogether
* Move block-time existence check into Blockstore::cache_block_time, Blockstore no longer needed in blockstore_processor helper
CodingShredHeader.position is equal to
ShredCommonHeader.index - ShredCommonHeader.fec_set_index
and is so redundant. The extra position field can add bugs if not
consistent with index and fec_set_index.
Having an ordinal index on crds values based on insert order allows to
efficiently filter values using a cursor. In particular
CrdsGossipPush::push_messages hash-map can be replaced with a cursor,
saving on the bookkeepings, purging, etc
VersionedCrdsValue.insert_timestamp is used for fetching crds values
inserted since last query:
https://github.com/solana-labs/solana/blob/ec37a843a/core/src/cluster_info.rs#L1197-L1215https://github.com/solana-labs/solana/blob/ec37a843a/core/src/cluster_info.rs#L1274-L1298
So it is crucial that insert_timestamp does not go backward in time when
new values are inserted into the table. However std::time::SystemTime is
not monotonic, or due to workload, lock contention, thread scheduling,
etc, ... new values may be inserted with a stalled timestamp way in the
past. Additionally, reading system time for the above purpose is
inefficient/unnecessary.
This commit adds an ordinal index to crds values indicating their insert
order. Additionally, it implements a new Cursor type for fetching values
inserted since last query.
IP addresses need to be validated before sending packets to them.
This commit, sends a ping packet to nodes before any pull requests.
Pull requests are then only sent to the nodes which have responded with
the correct hash of their respective ping packet.
It is crucial that VersionedCrdsValue::insert_timestamp does not go
backward in time:
https://github.com/solana-labs/solana/blob/ec37a843a/core/src/crds.rs#L67-L79
Otherwise methods such as get_votes and get_epoch_slots_since will
break, which will break their downstream flow, including vote-listener
and optimistic confirmation:
https://github.com/solana-labs/solana/blob/ec37a843a/core/src/cluster_info.rs#L1197-L1215https://github.com/solana-labs/solana/blob/ec37a843a/core/src/cluster_info.rs#L1274-L1298
For that, Crds::new_versioned is intended to be called "atomically" with
Crds::insert_verioned (as the comment already says so):
https://github.com/solana-labs/solana/blob/ec37a843a/core/src/crds.rs#L126-L129
However, currently this is violated in the code. For example,
filter_pull_responses creates VersionedCrdsValues (with the current
timestamp), then acquires an exclusive lock on gossip, then
process_pull_responses writes those values to the crds table:
https://github.com/solana-labs/solana/blob/ec37a843a/core/src/cluster_info.rs#L2375-L2392
Depending on the workload and lock contention, the insert_timestamps may
well be in the past when these values finally are inserted into gossip.
To avoid such scenarios, this commit:
* removes Crds::new_versioned and Crd::insert_versioned.
* makes VersionedCrdsValue constructor private, only invoked in
Crds::insert, so that insert_timestamp is populated right before
insert.
This will improve insert_timestamp monotonicity as long as Crds::insert
is not called with a stalled timestamp. Following commits may further
improve this by calling timestamp() inside Crds::insert, and/or
switching to std::time::Instant which guarantees monotonicity.
Strip the zero-padding off of data shreds before insertion into blockstore
Co-authored-by: Stephen Akridge <sakridge@gmail.com>
Co-authored-by: Nathan Hawkins <utsl@utsl.org>
Local timestamps are updated for records associated with a pubkey if the
origin is still active:
https://github.com/solana-labs/solana/blob/c8ed14c64/core/src/crds.rs#L301-L311
However this is done inconsistently on some gossip paths (pull requests
and pull responses) but not all (e.g. push messages). Additionally
update_record_timestamp is inefficient since there can be ~800 values
associated with each pubkey.
This commit updates records timestamps only on contact-infos; and,
instead utilizes origin's timestamp when purging old values.
Number of parity coding shreds is always less than the number of data
shreds in FEC blocks:
https://github.com/solana-labs/solana/blob/6907a2366/ledger/src/shred.rs#L719
Data shreds are batched in chunks of 32 shreds each:
https://github.com/solana-labs/solana/blob/6907a2366/ledger/src/shred.rs#L714
However the very last batch of data shreds in a slot can be small, in
which case the loss rate can be exacerbated.
This commit expands the number of coding shreds in the last FEC block in
slots to: 64 - number of data shreds; so that FEC blocks are always 64
data and parity coding shreds each.
As a consequence of this, the last FEC block has more parity coding
shreds than data shreds. So for some shred indices we will have a coding
shred but no data shreds. This should not cause any kind of overlapping
FEC blocks as in:
https://github.com/solana-labs/solana/pull/10095
since this is done only for the very last batch in a slot, and the next
slot will reset the shred index.
behzad nouri
Lijun Wang
Tyera Eulberg
Jeff Washington (jwash)
Michael Vines
Trent Nelson
carllin
publish-docs.sh
Justin Starry
steviez
sakridge