From 64392209e95189a98181fab68c86b241c63708ca Mon Sep 17 00:00:00 2001
From: Bjerg <onbjerg@users.noreply.github.com>
Date: Thu, 15 Jun 2023 13:57:46 +0200
Subject: [PATCH] perf: reduce allocations in changeset helpers (#3169)

---
 .../src/providers/database/provider.rs        | 57 +++++++++----------
 1 file changed, 26 insertions(+), 31 deletions(-)

diff --git a/crates/storage/provider/src/providers/database/provider.rs b/crates/storage/provider/src/providers/database/provider.rs
index a355a09e63..5a1cd977a1 100644
--- a/crates/storage/provider/src/providers/database/provider.rs
+++ b/crates/storage/provider/src/providers/database/provider.rs
@@ -265,23 +265,22 @@ impl<'this, TX: DbTx<'this>> DatabaseProvider<'this, TX> {
         &self,
         range: RangeInclusive<BlockNumber>,
     ) -> std::result::Result<BTreeMap<(Address, H256), Vec<u64>>, TransactionError> {
-        let storage_changeset = self
-            .tx
-            .cursor_read::<tables::StorageChangeSet>()?
-            .walk_range(BlockNumberAddress::range(range))?
-            .collect::<std::result::Result<Vec<_>, _>>()?;
+        let mut changeset_cursor = self.tx.cursor_read::<tables::StorageChangeSet>()?;
 
-        // fold all storages to one set of changes
-        let storage_changeset_lists = storage_changeset.into_iter().fold(
-            BTreeMap::new(),
-            |mut storages: BTreeMap<(Address, H256), Vec<u64>>, (index, storage)| {
-                storages
-                    .entry((index.address(), storage.key))
-                    .or_default()
-                    .push(index.block_number());
-                storages
-            },
-        );
+        let storage_changeset_lists =
+            changeset_cursor.walk_range(BlockNumberAddress::range(range))?.try_fold(
+                BTreeMap::new(),
+                |mut storages: BTreeMap<(Address, H256), Vec<u64>>,
+                 entry|
+                 -> std::result::Result<_, TransactionError> {
+                    let (index, storage) = entry?;
+                    storages
+                        .entry((index.address(), storage.key))
+                        .or_default()
+                        .push(index.block_number());
+                    Ok(storages)
+                },
+            )?;
 
         Ok(storage_changeset_lists)
     }
@@ -293,22 +292,18 @@ impl<'this, TX: DbTx<'this>> DatabaseProvider<'this, TX> {
         &self,
         range: RangeInclusive<BlockNumber>,
     ) -> std::result::Result<BTreeMap<Address, Vec<u64>>, TransactionError> {
-        let account_changesets = self
-            .tx
-            .cursor_read::<tables::AccountChangeSet>()?
-            .walk_range(range)?
-            .collect::<std::result::Result<Vec<_>, _>>()?;
+        let mut changeset_cursor = self.tx.cursor_read::<tables::AccountChangeSet>()?;
 
-        let account_transtions = account_changesets
-            .into_iter()
-            // fold all account to one set of changed accounts
-            .fold(
-                BTreeMap::new(),
-                |mut accounts: BTreeMap<Address, Vec<u64>>, (index, account)| {
-                    accounts.entry(account.address).or_default().push(index);
-                    accounts
-                },
-            );
+        let account_transtions = changeset_cursor.walk_range(range)?.try_fold(
+            BTreeMap::new(),
+            |mut accounts: BTreeMap<Address, Vec<u64>>,
+             entry|
+             -> std::result::Result<_, TransactionError> {
+                let (index, account) = entry?;
+                accounts.entry(account.address).or_default().push(index);
+                Ok(accounts)
+            },
+        )?;
 
         Ok(account_transtions)
     }