Sampling for chain blocks

components/consensusmanager/src/session.rs

@@ -236,6 +236,10 @@ impl ConsensusSessionOwned {
         self.clone().spawn_blocking(|c| c.get_headers_selected_tip()).await
     }
 
+    pub async fn async_get_chain_block_samples(&self) -> Vec<Arc<Header>> {
+        self.clone().spawn_blocking(|c| c.get_chain_block_samples()).await
+    }
+
     /// Returns the anticone of block `hash` from the POV of `context`, i.e. `anticone(hash) ∩ past(context)`.
     /// Since this might be an expensive operation for deep blocks, we allow the caller to specify a limit
     /// `max_traversal_allowed` on the maximum amount of blocks to traverse for obtaining the answer

consensus/core/src/api/mod.rs

@@ -93,6 +93,10 @@ pub trait ConsensusApi: Send + Sync {
         unimplemented!()
     }
 
+    fn get_chain_block_samples(&self) -> Vec<Arc<Header>> {
+        unimplemented!()
+    }
+
     fn get_virtual_parents(&self) -> BlockHashSet {
         unimplemented!()
     }

consensus/src/consensus/mod.rs

@@ -78,6 +78,8 @@ use tokio::sync::oneshot;
 
 use self::{services::ConsensusServices, storage::ConsensusStorage};
 
+use crate::model::stores::selected_chain::SelectedChainStoreReader;
+
 pub struct Consensus {
     // DB
     db: Arc<DB>,
@@ -438,6 +440,26 @@ impl ConsensusApi for Consensus {
         Ok(self.services.dag_traversal_manager.calculate_chain_path(hash, self.get_sink()))
     }
 
+    /// Returns a Vec of header samples since genesis
+    /// Ordered ascending by daa_score, first entry is genesis
+    fn get_chain_block_samples(&self) -> Vec<Arc<Header>> {
+        // Sorted from genesis to latest pruning_point_headers
+        let mut pp_headers = self.pruning_point_headers();
+        let sc_read = self.storage.selected_chain_store.read();
+        let low = pp_headers.last().unwrap().hash;
+        let high = sc_read.get_tip().unwrap().1;
+
+        let low_index = sc_read.get_by_hash(low).unwrap_option().unwrap_or(0);
+        let high_index = sc_read.get_by_hash(high).unwrap_option().unwrap_or(0);
+        let step_size = (high_index - low_index) / 3;
+
+        for index in (low_index+step_size..=high_index).step_by(step_size as usize) {
+            pp_headers.push(self.storage.headers_store.get_header(sc_read.get_by_index(index).unwrap()).unwrap());
+        }
+
+        pp_headers
+    }
+
     fn get_virtual_parents(&self) -> BlockHashSet {
         self.virtual_stores.read().state.get().unwrap().parents.iter().copied().collect()
     }

rpc/service/src/service.rs

@@ -517,12 +517,10 @@ impl RpcApi for RpcCoreService {
         request: GetDaaScoreTimestampEstimateRequest,
     ) -> RpcResult<GetDaaScoreTimestampEstimateResponse> {
         let session = self.consensus_manager.consensus().session().await;
-        let mut headers = session.async_pruning_point_headers().await;
+        let headers = session.async_get_chain_block_samples().await;
         let mut requested_daa_scores = request.daa_scores.clone();
         let mut daa_score_timestamp_map = HashMap::<u64, u64>::new();
 
-        // TODO: Add more headers here from recent times, after last pp. Do so before reversing
-        headers.reverse();
         requested_daa_scores.sort_by(|a, b| b.cmp(a));
 
         let mut header_idx = 0;