Simplify aristo tree deletion functionality (#2563)

* Cleaning up, removing cruft and debugging statements

* Make `aristo_delta` fluffy compatible

why:
  A sub-module that uses `chronicles` must import all possible
  modules used by a parent module that imports the sub-module.

* update TODO

fluffy/fluffy.nim.cfg

@@ -1,11 +1,4 @@
-#
-# For some reason `json[dynamic]` causes problems with subsequent modules from
-# `Aristo` when compiling `fluffy`. There might be a `chronicles` inport missing
-# but it is not obvious where. -- jordan
-#
-#-d:"chronicles_sinks=textlines[dynamic],json[dynamic]"
-
--d:"chronicles_sinks=textlines[dynamic]"
+-d:"chronicles_sinks=textlines[dynamic],json[dynamic]"
 -d:"chronicles_runtime_filtering=on"
 -d:"chronicles_disable_thread_id"
 

fluffy/tools/beacon_lc_bridge/nim.cfg

@@ -1,6 +1,5 @@
 # Use only `secp256k1` public key cryptography as an identity in LibP2P.
 -d:"libp2p_pki_schemes=secp256k1"
 
-# See `fluffy.nim.cfg`
-#-d:"chronicles_sinks=textlines[dynamic],json[dynamic]"
+-d:"chronicles_sinks=textlines[dynamic],json[dynamic]"
 -d:"chronicles_sinks=textlines[dynamic]"

fluffy/tools/portal_bridge/nim.cfg

@@ -1,3 +1,2 @@
-# See `fluffy.nim.cfg`
-#-d:"chronicles_sinks=textlines[dynamic],json[dynamic]"
+-d:"chronicles_sinks=textlines[dynamic],json[dynamic]"
 -d:"chronicles_sinks=textlines[dynamic]"

nimbus/db/aristo/TODO.md

@@ -11,3 +11,10 @@
 	function mentioned above.
 
 * `aristo_nearby` also qualifies for a re-write, now
+
+* Revisit tree deletion. The idea is to finally use ranges of nodes by
+  exploiting the root ID prefix of a `RootedVertexID`. The `RocksDb` backend
+  seems to support this kind of operation, see
+  https://rocksdb.org/blog/2018/11/21/delete-range.html. For the application
+  part there are some great ideas floating which need to be followed up
+  some time.

nimbus/db/aristo/aristo_constants.nim

@@ -42,15 +42,6 @@ const
     ## LRU cache size for accounts that have storage, see `.accLeaves` and
     ## `.stoLeaves` fields of the main descriptor.
 
-  DELETE_SUBTREE_VERTICES_MAX* = 25
-    ## Maximum number of vertices for a tree to be deleted instantly. If the
-    ## tree is larger, only the sub-tree root will be deleted immediately and
-    ## subsequent entries will be deleted not until the cache layers are saved
-    ## to the backend.
-    ##
-    ## Set to zero to disable in which case all sub-trees are deleted
-    ## immediately.
-
 static:
   # must stay away from `VertexID(1)` and `VertexID(2)`
   doAssert 2 < LEAST_FREE_VID

nimbus/db/aristo/aristo_delete/delete_subtree.nim

@@ -8,13 +8,109 @@
 # at your option. This file may not be copied, modified, or distributed
 # except according to those terms.
 
-import ../aristo_constants
+{.push raises: [].}
 
-when DELETE_SUBTREE_VERTICES_MAX == 0:
-  import ./delete_subtree_now as del_sub
-else:
-  import ./delete_subtree_lazy as del_sub
+import
+  eth/common,
+  results,
+  ".."/[aristo_desc, aristo_get, aristo_layers],
+  ./delete_helpers
 
-export del_sub
+# ------------------------------------------------------------------------------
+# Private heplers
+# ------------------------------------------------------------------------------
 
+proc collectStoTreeLazily(
+  db: AristoDbRef;                     # Database, top layer
+  rvid: RootedVertexID;                # Root vertex
+  accPath: Hash256;                    # Accounts cache designator
+  stoPath: NibblesBuf;                 # Current storage path
+    ): Result[void,AristoError] =
+  ## Collect vertex/vid and delete cache entries.
+  let (vtx, _) = db.getVtxRc(rvid).valueOr:
+    if error == GetVtxNotFound:
+      return ok()
+    return err(error)
+
+  case vtx.vType
+  of Branch:
+    for i in 0..15:
+      if vtx.bVid[i].isValid:
+        ? db.collectStoTreeLazily(
+          (rvid.root, vtx.bVid[i]), accPath,
+          stoPath & vtx.ePfx & NibblesBuf.nibble(byte i))
+
+  of Leaf:
+    let stoPath = Hash256(data: (stoPath & vtx.lPfx).getBytes())
+    db.layersPutStoLeaf(AccountKey.mixUp(accPath, stoPath), nil)
+
+  # There is no useful approach avoiding to walk the whole tree for updating
+  # the storage data access cache.
+  #
+  # The alternative of stopping here and clearing the whole cache did degrade
+  # performance significantly in some tests on mainnet when importing `era1`.
+  #
+  # The cache it was seen
+  # * filled up to maximum size most of the time
+  # * at the same time having no `stoPath` hit at all (so there was nothing
+  #   to be cleared.)
+  #
+  ok()
+
+
+proc disposeOfSubTree(
+    db: AristoDbRef;                   # Database, top layer
+    rvid: RootedVertexID;              # Root vertex
+      ) =
+  ## Evaluate results from `collectSubTreeLazyImpl()` or ftom
+  ## `collectStoTreeLazyImpl)`.
+  ##
+  let vtx = db.getVtxRc(rvid).value[0]
+  if vtx.vType == Branch:
+    for n in 0..15:
+      if vtx.bVid[n].isValid:
+        db.top.delTree.add (rvid.root,vtx.bVid[n])
+
+  # Delete top of tree now.
+  db.disposeOfVtx(rvid)
+
+# ------------------------------------------------------------------------------
+# Public functions
+# ------------------------------------------------------------------------------
+
+proc delSubTreeImpl*(
+    db: AristoDbRef;                   # Database, top layer
+    root: VertexID;                    # Root vertex
+      ): Result[void,AristoError] =
+  ## Delete all the `subRoots`if there are a few, only. Otherwise
+  ## mark it for deleting later.
+  discard db.getVtxRc((root,root)).valueOr:
+    if error == GetVtxNotFound:
+      return ok()
+    return err(error)
+
+  db.disposeOfSubTree((root,root))
+
+  ok()
+
+
+proc delStoTreeImpl*(
+    db: AristoDbRef;                   # Database, top layer
+    rvid: RootedVertexID;              # Root vertex
+    accPath: Hash256;
+      ): Result[void,AristoError] =
+  ## Collect vertex/vid and cache entry.
+  discard db.getVtxRc(rvid).valueOr:
+    if error == GetVtxNotFound:
+      return ok()
+    return err(error)
+
+  ? db.collectStoTreeLazily(rvid, accPath, NibblesBuf())
+
+  db.disposeOfSubTree(rvid)
+
+  ok()
+
+# ------------------------------------------------------------------------------
 # End
+# ------------------------------------------------------------------------------