Data column custody info (#7648)

#7647


  Introduces a new record in the blobs db `DataColumnCustodyInfo`

When `DataColumnCustodyInfo` exists in the db this indicates that a recent cgc change has occurred and/or that a custody backfill sync is currently in progress (custody backfill will be added as a separate PR). When a cgc change has occurred `earliest_available_slot` will be equal to the slot at which the cgc change occured. During custody backfill sync`earliest_available_slot` should be updated incrementally as it progresses.

~~Note that if `advertise_false_custody_group_count` is enabled we do not add a `DataColumnCustodyInfo` record in the db as that would affect the status v2 response.~~
(See comment https://github.com/sigp/lighthouse/pull/7648#discussion_r2212403389)

~~If `DataColumnCustodyInfo` doesn't exist in the db this indicates that we have fulfilled our custody requirements up to the DA window.~~
(It now always exist, and the slot will be set to `None` once backfill is complete)

StatusV2 now uses `DataColumnCustodyInfo` to calculate the `earliest_available_slot` if a `DataColumnCustodyInfo` record exists in the db, if it's `None`, then we return the `oldest_block_slot`.

beacon_node/store/src/hot_cold_store.rs

@@ -6,10 +6,10 @@ use crate::historic_state_cache::HistoricStateCache;
 use crate::iter::{BlockRootsIterator, ParentRootBlockIterator, RootsIterator};
 use crate::memory_store::MemoryStore;
 use crate::metadata::{
-    AnchorInfo, BlobInfo, CompactionTimestamp, DataColumnInfo, SchemaVersion, ANCHOR_INFO_KEY,
-    ANCHOR_UNINITIALIZED, BLOB_INFO_KEY, COMPACTION_TIMESTAMP_KEY, CONFIG_KEY,
-    CURRENT_SCHEMA_VERSION, DATA_COLUMN_INFO_KEY, SCHEMA_VERSION_KEY, SPLIT_KEY,
-    STATE_UPPER_LIMIT_NO_RETAIN,
+    AnchorInfo, BlobInfo, CompactionTimestamp, DataColumnCustodyInfo, DataColumnInfo,
+    SchemaVersion, ANCHOR_INFO_KEY, ANCHOR_UNINITIALIZED, BLOB_INFO_KEY, COMPACTION_TIMESTAMP_KEY,
+    CONFIG_KEY, CURRENT_SCHEMA_VERSION, DATA_COLUMN_CUSTODY_INFO_KEY, DATA_COLUMN_INFO_KEY,
+    SCHEMA_VERSION_KEY, SPLIT_KEY, STATE_UPPER_LIMIT_NO_RETAIN,
 };
 use crate::state_cache::{PutStateOutcome, StateCache};
 use crate::{
@@ -91,6 +91,7 @@ struct BlockCache<E: EthSpec> {
     block_cache: LruCache<Hash256, SignedBeaconBlock<E>>,
     blob_cache: LruCache<Hash256, BlobSidecarList<E>>,
     data_column_cache: LruCache<Hash256, HashMap<ColumnIndex, Arc<DataColumnSidecar<E>>>>,
+    data_column_custody_info_cache: Option<DataColumnCustodyInfo>,
 }
 
 impl<E: EthSpec> BlockCache<E> {
@@ -99,6 +100,7 @@ impl<E: EthSpec> BlockCache<E> {
             block_cache: LruCache::new(size),
             blob_cache: LruCache::new(size),
             data_column_cache: LruCache::new(size),
+            data_column_custody_info_cache: None,
         }
     }
     pub fn put_block(&mut self, block_root: Hash256, block: SignedBeaconBlock<E>) {
@@ -112,6 +114,12 @@ impl<E: EthSpec> BlockCache<E> {
             .get_or_insert_mut(block_root, Default::default)
             .insert(data_column.index, data_column);
     }
+    pub fn put_data_column_custody_info(
+        &mut self,
+        data_column_custody_info: Option<DataColumnCustodyInfo>,
+    ) {
+        self.data_column_custody_info_cache = data_column_custody_info;
+    }
     pub fn get_block<'a>(&'a mut self, block_root: &Hash256) -> Option<&'a SignedBeaconBlock<E>> {
         self.block_cache.get(block_root)
     }
@@ -129,6 +137,9 @@ impl<E: EthSpec> BlockCache<E> {
             .get(block_root)
             .and_then(|map| map.get(column_index).cloned())
     }
+    pub fn get_data_column_custody_info(&self) -> Option<DataColumnCustodyInfo> {
+        self.data_column_custody_info_cache.clone()
+    }
     pub fn delete_block(&mut self, block_root: &Hash256) {
         let _ = self.block_cache.pop(block_root);
     }
@@ -922,6 +933,24 @@ impl<E: EthSpec, Hot: ItemStore<E>, Cold: ItemStore<E>> HotColdDB<E, Hot, Cold>
         ));
     }
 
+    pub fn put_data_column_custody_info(
+        &self,
+        earliest_data_column_slot: Option<Slot>,
+    ) -> Result<(), Error> {
+        let data_column_custody_info = DataColumnCustodyInfo {
+            earliest_data_column_slot,
+        };
+
+        self.blobs_db
+            .put(&DATA_COLUMN_CUSTODY_INFO_KEY, &data_column_custody_info)?;
+
+        self.block_cache
+            .lock()
+            .put_data_column_custody_info(Some(data_column_custody_info));
+
+        Ok(())
+    }
+
     pub fn put_data_columns(
         &self,
         block_root: &Hash256,
@@ -2389,6 +2418,27 @@ impl<E: EthSpec, Hot: ItemStore<E>, Cold: ItemStore<E>> HotColdDB<E, Hot, Cold>
             })
     }
 
+    /// Fetch custody info from the cache.
+    /// If custody info doesn't exist in the cache,
+    /// try to fetch from the DB and prime the cache.
+    pub fn get_data_column_custody_info(&self) -> Result<Option<DataColumnCustodyInfo>, Error> {
+        let Some(data_column_custody_info) = self.block_cache.lock().get_data_column_custody_info()
+        else {
+            let data_column_custody_info = self
+                .blobs_db
+                .get::<DataColumnCustodyInfo>(&DATA_COLUMN_CUSTODY_INFO_KEY)?;
+
+            // Update the cache
+            self.block_cache
+                .lock()
+                .put_data_column_custody_info(data_column_custody_info.clone());
+
+            return Ok(data_column_custody_info);
+        };
+
+        Ok(Some(data_column_custody_info))
+    }
+
     /// Fetch all columns for a given block from the store.
     pub fn get_data_columns(
         &self,