trie: cache collapsed tries node, not rlp blobs (#16876)

The current trie memory database/cache that we do pruning on stores
trie nodes as binary rlp encoded blobs, and also stores the node
relationships/references for GC purposes. However, most of the trie
nodes (everything apart from a value node) is in essence just a
collection of references.

This PR switches out the RLP encoded trie blobs with the
collapsed-but-not-serialized trie nodes. This permits most of the
references to be recovered from within the node data structure,
avoiding the need to track them a second time (expensive memory wise).

1 files changed, 3 insertions, 3 deletions

diff --git a/eth/api_tracer.go b/eth/api_tracer.go
index 61f5c71d6..623e5ed1b 100644
--- a/eth/api_tracer.go
+++ b/eth/api_tracer.go
@@ -297,7 +297,7 @@ func (api *PrivateDebugAPI) traceChain(ctx context.Context, start, end *types.Bl
 				database.TrieDB().Reference(root, common.Hash{})
 			}
 			// Dereference all past tries we ourselves are done working with
-			database.TrieDB().Dereference(proot, common.Hash{})
+			database.TrieDB().Dereference(proot)
 			proot = root
 
 			// TODO(karalabe): Do we need the preimages? Won't they accumulate too much?
@@ -320,7 +320,7 @@ func (api *PrivateDebugAPI) traceChain(ctx context.Context, start, end *types.Bl
 			done[uint64(result.Block)] = result
 
 			// Dereference any paret tries held in memory by this task
-			database.TrieDB().Dereference(res.rootref, common.Hash{})
+			database.TrieDB().Dereference(res.rootref)
 
 			// Stream completed traces to the user, aborting on the first error
 			for result, ok := done[next]; ok; result, ok = done[next] {
@@ -526,7 +526,7 @@ func (api *PrivateDebugAPI) computeStateDB(block *types.Block, reexec uint64) (*
 			return nil, err
 		}
 		database.TrieDB().Reference(root, common.Hash{})
-		database.TrieDB().Dereference(proot, common.Hash{})
+		database.TrieDB().Dereference(proot)
 		proot = root
 	}
 	nodes, imgs := database.TrieDB().Size()