Separate execution payloads in the DB (#3157)

## Proposed Changes

Reduce post-merge disk usage by not storing finalized execution payloads in Lighthouse's database.

⚠️ **This is achieved in a backwards-incompatible way for networks that have already merged** ⚠️. Kiln users and shadow fork enjoyers will be unable to downgrade after running the code from this PR. The upgrade migration may take several minutes to run, and can't be aborted after it begins.

The main changes are:

- New column in the database called `ExecPayload`, keyed by beacon block root.
- The `BeaconBlock` column now stores blinded blocks only.
- Lots of places that previously used full blocks now use blinded blocks, e.g. analytics APIs, block replay in the DB, etc.
- On finalization:
    - `prune_abanonded_forks` deletes non-canonical payloads whilst deleting non-canonical blocks.
    - `migrate_db` deletes finalized canonical payloads whilst deleting finalized states.
- Conversions between blinded and full blocks are implemented in a compositional way, duplicating some work from Sean's PR #3134.
- The execution layer has a new `get_payload_by_block_hash` method that reconstructs a payload using the EE's `eth_getBlockByHash` call.
   - I've tested manually that it works on Kiln, using Geth and Nethermind.
   - This isn't necessarily the most efficient method, and new engine APIs are being discussed to improve this: https://github.com/ethereum/execution-apis/pull/146.
   - We're depending on the `ethers` master branch, due to lots of recent changes. We're also using a workaround for https://github.com/gakonst/ethers-rs/issues/1134.
- Payload reconstruction is used in the HTTP API via `BeaconChain::get_block`, which is now `async`. Due to the `async` fn, the `blocking_json` wrapper has been removed.
- Payload reconstruction is used in network RPC to serve blocks-by-{root,range} responses. Here the `async` adjustment is messier, although I think I've managed to come up with a reasonable compromise: the handlers take the `SendOnDrop` by value so that they can drop it on _task completion_ (after the `fn` returns). Still, this is introducing disk reads onto core executor threads, which may have a negative performance impact (thoughts appreciated).

## Additional Info

- [x] For performance it would be great to remove the cloning of full blocks when converting them to blinded blocks to write to disk. I'm going to experiment with a `put_block` API that takes the block by value, breaks it into a blinded block and a payload, stores the blinded block, and then re-assembles the full block for the caller.
- [x] We should measure the latency of blocks-by-root and blocks-by-range responses.
- [x] We should add integration tests that stress the payload reconstruction (basic tests done, issue for more extensive tests: https://github.com/sigp/lighthouse/issues/3159)
- [x] We should (manually) test the schema v9 migration from several prior versions, particularly as blocks have changed on disk and some migrations rely on being able to load blocks.

Co-authored-by: Paul Hauner <paul@paulhauner.com>

beacon_node/beacon_chain/src/beacon_chain.rs

@@ -83,8 +83,11 @@ use std::marker::PhantomData;
 use std::sync::Arc;
 use std::time::{Duration, Instant};
 use store::iter::{BlockRootsIterator, ParentRootBlockIterator, StateRootsIterator};
-use store::{Error as DBError, HotColdDB, KeyValueStore, KeyValueStoreOp, StoreItem, StoreOp};
+use store::{
+    DatabaseBlock, Error as DBError, HotColdDB, KeyValueStore, KeyValueStoreOp, StoreItem, StoreOp,
+};
 use task_executor::ShutdownReason;
+use tree_hash::TreeHash;
 use types::beacon_state::CloneConfig;
 use types::*;
 
@@ -587,7 +590,7 @@ impl<T: BeaconChainTypes> BeaconChain<T> {
         block_root: Hash256,
     ) -> Result<impl Iterator<Item = Result<(Hash256, Slot), Error>> + '_, Error> {
         let block = self
-            .get_block(&block_root)?
+            .get_blinded_block(&block_root)?
             .ok_or(Error::MissingBeaconBlock(block_root))?;
         let state = self
             .get_state(&block.state_root(), Some(block.slot()))?
@@ -752,11 +755,11 @@ impl<T: BeaconChainTypes> BeaconChain<T> {
         &self,
         request_slot: Slot,
         skips: WhenSlotSkipped,
-    ) -> Result<Option<SignedBeaconBlock<T::EthSpec>>, Error> {
+    ) -> Result<Option<SignedBlindedBeaconBlock<T::EthSpec>>, Error> {
         let root = self.block_root_at_slot(request_slot, skips)?;
 
         if let Some(block_root) = root {
-            Ok(self.store.get_block(&block_root)?)
+            Ok(self.store.get_blinded_block(&block_root)?)
         } else {
             Ok(None)
         }
@@ -961,16 +964,14 @@ impl<T: BeaconChainTypes> BeaconChain<T> {
     /// ## Errors
     ///
     /// May return a database error.
-    pub fn get_block_checking_early_attester_cache(
+    pub async fn get_block_checking_early_attester_cache(
         &self,
         block_root: &Hash256,
     ) -> Result<Option<SignedBeaconBlock<T::EthSpec>>, Error> {
-        let block_opt = self
-            .store
-            .get_block(block_root)?
-            .or_else(|| self.early_attester_cache.get_block(*block_root));
-
-        Ok(block_opt)
+        if let Some(block) = self.early_attester_cache.get_block(*block_root) {
+            return Ok(Some(block));
+        }
+        self.get_block(block_root).await
     }
 
     /// Returns the block at the given root, if any.
@@ -978,11 +979,69 @@ impl<T: BeaconChainTypes> BeaconChain<T> {
     /// ## Errors
     ///
     /// May return a database error.
-    pub fn get_block(
+    pub async fn get_block(
         &self,
         block_root: &Hash256,
     ) -> Result<Option<SignedBeaconBlock<T::EthSpec>>, Error> {
-        Ok(self.store.get_block(block_root)?)
+        // Load block from database, returning immediately if we have the full block w payload
+        // stored.
+        let blinded_block = match self.store.try_get_full_block(block_root)? {
+            Some(DatabaseBlock::Full(block)) => return Ok(Some(block)),
+            Some(DatabaseBlock::Blinded(block)) => block,
+            None => return Ok(None),
+        };
+
+        // If we only have a blinded block, load the execution payload from the EL.
+        let block_message = blinded_block.message();
+        let execution_payload_header = &block_message
+            .execution_payload()
+            .map_err(|_| Error::BlockVariantLacksExecutionPayload(*block_root))?
+            .execution_payload_header;
+
+        let exec_block_hash = execution_payload_header.block_hash;
+
+        let execution_payload = self
+            .execution_layer
+            .as_ref()
+            .ok_or(Error::ExecutionLayerMissing)?
+            .get_payload_by_block_hash(exec_block_hash)
+            .await
+            .map_err(|e| Error::ExecutionLayerErrorPayloadReconstruction(exec_block_hash, e))?
+            .ok_or(Error::BlockHashMissingFromExecutionLayer(exec_block_hash))?;
+
+        // Verify payload integrity.
+        let header_from_payload = ExecutionPayloadHeader::from(&execution_payload);
+        if header_from_payload != *execution_payload_header {
+            for txn in &execution_payload.transactions {
+                debug!(
+                    self.log,
+                    "Reconstructed txn";
+                    "bytes" => format!("0x{}", hex::encode(&**txn)),
+                );
+            }
+
+            return Err(Error::InconsistentPayloadReconstructed {
+                slot: blinded_block.slot(),
+                exec_block_hash,
+                canonical_payload_root: execution_payload_header.tree_hash_root(),
+                reconstructed_payload_root: header_from_payload.tree_hash_root(),
+                canonical_transactions_root: execution_payload_header.transactions_root,
+                reconstructed_transactions_root: header_from_payload.transactions_root,
+            });
+        }
+
+        // Add the payload to the block to form a full block.
+        blinded_block
+            .try_into_full_block(Some(execution_payload))
+            .ok_or(Error::AddPayloadLogicError)
+            .map(Some)
+    }
+
+    pub fn get_blinded_block(
+        &self,
+        block_root: &Hash256,
+    ) -> Result<Option<SignedBlindedBeaconBlock<T::EthSpec>>, Error> {
+        Ok(self.store.get_blinded_block(block_root)?)
     }
 
     /// Returns the state at the given root, if any.
@@ -3373,7 +3432,8 @@ impl<T: BeaconChainTypes> BeaconChain<T> {
             .map::<Result<_, Error>, _>(Ok)
             .unwrap_or_else(|| {
                 let beacon_block = self
-                    .get_block(&beacon_block_root)?
+                    .store
+                    .get_full_block(&beacon_block_root)?
                     .ok_or(Error::MissingBeaconBlock(beacon_block_root))?;
 
                 let beacon_state_root = beacon_block.state_root();
@@ -4525,11 +4585,14 @@ impl<T: BeaconChainTypes> BeaconChain<T> {
     ///
     /// This could be a very expensive operation and should only be done in testing/analysis
     /// activities.
-    pub fn chain_dump(&self) -> Result<Vec<BeaconSnapshot<T::EthSpec>>, Error> {
+    #[allow(clippy::type_complexity)]
+    pub fn chain_dump(
+        &self,
+    ) -> Result<Vec<BeaconSnapshot<T::EthSpec, BlindedPayload<T::EthSpec>>>, Error> {
         let mut dump = vec![];
 
         let mut last_slot = BeaconSnapshot {
-            beacon_block: self.head()?.beacon_block,
+            beacon_block: self.head()?.beacon_block.into(),
             beacon_block_root: self.head()?.beacon_block_root,
             beacon_state: self.head()?.beacon_state,
         };
@@ -4543,9 +4606,12 @@ impl<T: BeaconChainTypes> BeaconChain<T> {
                 break; // Genesis has been reached.
             }
 
-            let beacon_block = self.store.get_block(&beacon_block_root)?.ok_or_else(|| {
-                Error::DBInconsistent(format!("Missing block {}", beacon_block_root))
-            })?;
+            let beacon_block = self
+                .store
+                .get_blinded_block(&beacon_block_root)?
+                .ok_or_else(|| {
+                    Error::DBInconsistent(format!("Missing block {}", beacon_block_root))
+                })?;
             let beacon_state_root = beacon_block.state_root();
             let beacon_state = self
                 .store
@@ -4630,7 +4696,7 @@ impl<T: BeaconChainTypes> BeaconChain<T> {
                 visited.insert(block_hash);
 
                 if signed_beacon_block.slot() % T::EthSpec::slots_per_epoch() == 0 {
-                    let block = self.get_block(&block_hash).unwrap().unwrap();
+                    let block = self.get_blinded_block(&block_hash).unwrap().unwrap();
                     let state = self
                         .get_state(&block.state_root(), Some(block.slot()))
                         .unwrap()