fix: remove naive seen_txns cache (#32)

Author: anna-carroll

src/tasks/block.rs

@@ -153,7 +153,6 @@ impl BlockBuilder {
                 tracing::error!(error = %e, "error polling transactions");
             }
         }
-        self.tx_poller.evict();
     }
 
     async fn _get_bundles(&mut self, in_progress: &mut InProgressBlock) {

src/tasks/tx_poller.rs

@@ -1,18 +1,11 @@
-use std::time::Duration;
-use std::{collections::HashMap, time};
-
 use alloy::consensus::TxEnvelope;
-use alloy_primitives::TxHash;
-
 use eyre::Error;
 use reqwest::{Client, Url};
 use serde::{Deserialize, Serialize};
 use serde_json::from_slice;
 
 pub use crate::config::BuilderConfig;
 
-use metrics::counter;
-
 #[derive(Debug, Clone, Serialize, Deserialize)]
 pub struct TxPoolResponse {
     transactions: Vec<TxEnvelope>,
@@ -24,63 +17,21 @@ pub struct TxPoller {
     pub config: BuilderConfig,
     // Reqwest client for fetching transactions from the tx-pool
     pub client: Client,
-    //  Maintain a set of transaction hashes to their expiration times
-    pub seen_txns: HashMap<TxHash, time::Instant>,
 }
 
 /// TxPoller implements a poller that fetches unique transactions from the transaction pool.
 impl TxPoller {
     /// returns a new TxPoller with the given config.
     pub fn new(config: &BuilderConfig) -> Self {
-        Self { config: config.clone(), client: Client::new(), seen_txns: HashMap::new() }
+        Self { config: config.clone(), client: Client::new() }
     }
 
     /// polls the tx-pool for unique transactions and evicts expired transactions.
     /// unique transactions that haven't been seen before are sent into the builder pipeline.
     pub async fn check_tx_cache(&mut self) -> Result<Vec<TxEnvelope>, Error> {
-        let mut unique: Vec<TxEnvelope> = Vec::new();
-
         let url: Url = Url::parse(&self.config.tx_pool_url)?.join("transactions")?;
         let result = self.client.get(url).send().await?;
         let response: TxPoolResponse = from_slice(result.text().await?.as_bytes())?;
-
-        response.transactions.iter().for_each(|entry| {
-            self.check_seen_txs(entry.clone(), &mut unique);
-        });
-
-        Ok(unique)
-    }
-
-    /// checks if the transaction has been seen before and if not, adds it to the unique transactions list.
-    fn check_seen_txs(&mut self, tx: TxEnvelope, unique: &mut Vec<TxEnvelope>) {
-        self.seen_txns.entry(*tx.tx_hash()).or_insert_with(|| {
-            // add to unique transactions
-            unique.push(tx.clone());
-            counter!("builder.unique_txs").increment(1);
-            // expiry is now + cache_duration
-            time::Instant::now() + Duration::from_secs(self.config.tx_pool_cache_duration)
-        });
-    }
-
-    /// removes entries from seen_txns that have lived past expiry
-    pub fn evict(&mut self) {
-        let expired_keys: Vec<TxHash> = self
-            .seen_txns
-            .iter()
-            .filter_map(
-                |(key, &expiration)| {
-                    if !expiration.elapsed().is_zero() {
-                        Some(*key)
-                    } else {
-                        None
-                    }
-                },
-            )
-            .collect();
-
-        for key in expired_keys {
-            self.seen_txns.remove(&key);
-            counter!("builder.evicted_txs").increment(1);
-        }
+        Ok(response.transactions)
     }
 }