From debba5a620c9c15cf2499ee73c47325643b359e4 Mon Sep 17 00:00:00 2001
From: Jordan Hrycaj <jordan@status.im>
Date: Fri, 14 Jun 2024 11:19:48 +0000
Subject: [PATCH] Coeredb related clean up and maint fixes (#2360)

* Fix initialiser

why:
  Possible crash (app profiling, tracer etc.)

* Update column family options processing

why:
  Same for kvt as for aristo

* Move `AristoDbDualRocks` backend type to the test suite

why:
  So it is not available for production

* Fix typos in API jump table

why:
  Used for tracing and app profiling only. Needed some update

* Purged CoreDb legacy API

why:
  Not needed anymore, was transitionary and disabled.

* Rename `flush` argument to `eradicate` in a DB close context

why:
  The word `eradicate` leaves no doubt what is meant

* Rename `stoFlush()` -> `stoDelete()`

* Rename `core_apps_newapi` -> `core_apps` (not so new anymore)
---
 nimbus/db/aristo/aristo_api.nim               |  28 +-
 nimbus/db/aristo/aristo_desc/desc_backend.nim |  10 +-
 nimbus/db/aristo/aristo_init/memory_only.nim  |  12 +-
 nimbus/db/aristo/aristo_init/persistent.nim   |   2 +-
 nimbus/db/aristo/aristo_init/rocks_db.nim     |   4 +-
 .../aristo/aristo_init/rocks_db/rdb_init.nim  |   4 +-
 nimbus/db/core_db/backend/aristo_db.nim       |   6 +-
 .../backend/aristo_db/handlers_aristo.nim     |  12 +-
 .../backend/aristo_db/handlers_kvt.nim        |   4 +-
 .../backend/aristo_db/handlers_trace.nim      |   2 +-
 nimbus/db/core_db/backend/aristo_rocksdb.nim  |   2 +-
 nimbus/db/core_db/base.nim                    | 256 +-----------------
 nimbus/db/core_db/base/api_tracking.nim       |  79 +-----
 nimbus/db/core_db/base/base_desc.nim          |  13 +-
 nimbus/db/core_db/base/validate.nim           |   2 +-
 nimbus/db/core_db/base_iterators.nim          |  24 --
 .../db/core_db/base_iterators_persistent.nim  |  13 -
 .../{core_apps_newapi.nim => core_apps.nim}   |   0
 nimbus/db/core_db/memory_only.nim             |   7 +-
 nimbus/db/core_db/persistent.nim              |   8 -
 nimbus/db/kvt/kvt_api.nim                     |   2 +-
 nimbus/db/kvt/kvt_desc/desc_backend.nim       |  14 +-
 nimbus/db/kvt/kvt_init/memory_only.nim        |  14 +-
 nimbus/db/kvt/kvt_init/rocks_db.nim           |   6 +-
 nimbus/db/kvt/kvt_init/rocks_db/rdb_init.nim  |  49 +++-
 nimbus/db/ledger/distinct_ledgers.nim         |   4 +-
 nimbus/db/state_db/base.nim                   |   4 +-
 tests/test_aristo/test_filter.nim             |   6 +-
 tests/test_aristo/test_tx.nim                 |   8 +-
 tests/test_coredb.nim                         |  43 +--
 tests/test_coredb/test_coredb_helpers.nim     |  50 ++++
 31 files changed, 203 insertions(+), 485 deletions(-)
 rename nimbus/db/core_db/{core_apps_newapi.nim => core_apps.nim} (100%)
 create mode 100644 tests/test_coredb/test_coredb_helpers.nim

diff --git a/nimbus/db/aristo/aristo_api.nim b/nimbus/db/aristo/aristo_api.nim
index 6abbdb0b7..569b254ba 100644
--- a/nimbus/db/aristo/aristo_api.nim
+++ b/nimbus/db/aristo/aristo_api.nim
@@ -126,12 +126,12 @@ type
 
   AristoApiFinishFn* =
     proc(db: AristoDbRef;
-         flush = false;
+         eradicate = false;
         ) {.noRaise.}
-      ## Backend destructor. The argument `flush` indicates that a full
+      ## Backend destructor. The argument `eradicate` indicates that a full
       ## database deletion is requested. If set `false` the outcome might
       ## differ depending on the type of backend (e.g. the `BackendMemory`
-      ## backend will always flush on close.)
+      ## backend will always eradicate on close.)
       ##
       ## In case of distributed descriptors accessing the same backend, all
       ## distributed descriptors will be destroyed.
@@ -439,11 +439,11 @@ type
 
     AristoApiProfBeGetVtxFn            = "be/getVtx"
     AristoApiProfBeGetKeyFn            = "be/getKey"
-    AristoApiProfBeGetIdgFn            = "be/getIfg"
+    AristoApiProfBeGetTuvFn            = "be/getTuv"
     AristoApiProfBeGetLstFn            = "be/getLst"
     AristoApiProfBePutVtxFn            = "be/putVtx"
     AristoApiProfBePutKeyFn            = "be/putKey"
-    AristoApiProfBePutIdgFn            = "be/putIdg"
+    AristoApiProfBePutTuvFn            = "be/putTuv"
     AristoApiProfBePutLstFn            = "be/putLst"
     AristoApiProfBePutEndFn            = "be/putEnd"
 
@@ -757,11 +757,11 @@ func init*(
           result = be.getKeyFn(a)
     data.list[AristoApiProfBeGetKeyFn.ord].masked = true
 
-    beDup.getIdgFn =
+    beDup.getTuvFn =
       proc(): auto =
-        AristoApiProfBeGetIdgFn.profileRunner:
-          result = be.getIdgFn()
-    data.list[AristoApiProfBeGetIdgFn.ord].masked = true
+        AristoApiProfBeGetTuvFn.profileRunner:
+          result = be.getTuvFn()
+    data.list[AristoApiProfBeGetTuvFn.ord].masked = true
 
     beDup.getLstFn =
       proc(): auto =
@@ -781,11 +781,11 @@ func init*(
           be.putKeyFn(a,b)
     data.list[AristoApiProfBePutKeyFn.ord].masked = true
 
-    beDup.putIdgFn =
-      proc(a: PutHdlRef; b: openArray[VertexID]) =
-        AristoApiProfBePutIdgFn.profileRunner:
-          be.putIdgFn(a,b)
-    data.list[AristoApiProfBePutIdgFn.ord].masked = true
+    beDup.putTuvFn =
+      proc(a: PutHdlRef; b: VertexID) =
+        AristoApiProfBePutTuvFn.profileRunner:
+          be.putTuvFn(a,b)
+    data.list[AristoApiProfBePutTuvFn.ord].masked = true
 
     beDup.putLstFn =
       proc(a: PutHdlRef; b: SavedState) =
diff --git a/nimbus/db/aristo/aristo_desc/desc_backend.nim b/nimbus/db/aristo/aristo_desc/desc_backend.nim
index 44695c388..9c9181b28 100644
--- a/nimbus/db/aristo/aristo_desc/desc_backend.nim
+++ b/nimbus/db/aristo/aristo_desc/desc_backend.nim
@@ -82,11 +82,11 @@ type
   # -------------
 
   CloseFn* =
-    proc(flush: bool) {.gcsafe, raises: [].}
-      ## Generic destructor for the `Aristo DB` backend. The argument `flush`
-      ## indicates that a full database deletion is requested. If passed
-      ## `false` the outcome might differ depending on the type of backend
-      ## (e.g. in-memory backends would flush on close.)
+    proc(eradicate: bool) {.gcsafe, raises: [].}
+      ## Generic destructor for the `Aristo DB` backend. The argument
+      ## `eradicate` indicates that a full database deletion is requested. If
+      ## passed `false` the outcome might differ depending on the type of
+      ## backend (e.g. in-memory backends will always eradicate on close.)
 
   # -------------
 
diff --git a/nimbus/db/aristo/aristo_init/memory_only.nim b/nimbus/db/aristo/aristo_init/memory_only.nim
index fda2e17f7..dec011ae0 100644
--- a/nimbus/db/aristo/aristo_init/memory_only.nim
+++ b/nimbus/db/aristo/aristo_init/memory_only.nim
@@ -85,11 +85,11 @@ proc init*(
   AristoDbRef.init VoidBackendRef
 
 
-proc finish*(db: AristoDbRef; flush = false) =
-  ## Backend destructor. The argument `flush` indicates that a full database
-  ## deletion is requested. If set `false` the outcome might differ depending
-  ## on the type of backend (e.g. the `BackendMemory` backend will always
-  ## flush on close.)
+proc finish*(db: AristoDbRef; eradicate = false) =
+  ## Backend destructor. The argument `eradicate` indicates that a full
+  ## database deletion is requested. If set `false` the outcome might differ
+  ## depending on the type of backend (e.g. the `BackendMemory` backend will
+  ## always eradicate on close.)
   ##
   ## In case of distributed descriptors accessing the same backend, all
   ## distributed descriptors will be destroyed.
@@ -97,7 +97,7 @@ proc finish*(db: AristoDbRef; flush = false) =
   ## This distructor may be used on already *destructed* descriptors.
   ##
   if not db.backend.isNil:
-    db.backend.closeFn flush
+    db.backend.closeFn eradicate
   discard db.getCentre.forgetOthers()
 
 # ------------------------------------------------------------------------------
diff --git a/nimbus/db/aristo/aristo_init/persistent.nim b/nimbus/db/aristo/aristo_init/persistent.nim
index 02c384713..7f448f092 100644
--- a/nimbus/db/aristo/aristo_init/persistent.nim
+++ b/nimbus/db/aristo/aristo_init/persistent.nim
@@ -45,7 +45,7 @@ proc newAristoRdbDbRef(
     vTop = block:
       let rc = be.getTuvFn()
       if rc.isErr:
-        be.closeFn(flush = false)
+        be.closeFn(eradicate = false)
         return err(rc.error)
       rc.value
   ok AristoDbRef(
diff --git a/nimbus/db/aristo/aristo_init/rocks_db.nim b/nimbus/db/aristo/aristo_init/rocks_db.nim
index e7102abaf..1c9aa4d8d 100644
--- a/nimbus/db/aristo/aristo_init/rocks_db.nim
+++ b/nimbus/db/aristo/aristo_init/rocks_db.nim
@@ -225,8 +225,8 @@ proc putEndFn(db: RdbBackendRef): PutEndFn =
 
 proc closeFn(db: RdbBackendRef): CloseFn =
   result =
-    proc(flush: bool) =
-      db.rdb.destroy(flush)
+    proc(eradicate: bool) =
+      db.rdb.destroy(eradicate)
 
 # ------------------------------------------------------------------------------
 # Private functions: hosting interface changes
diff --git a/nimbus/db/aristo/aristo_init/rocks_db/rdb_init.nim b/nimbus/db/aristo/aristo_init/rocks_db/rdb_init.nim
index 34c71ee66..3dcffc6a4 100644
--- a/nimbus/db/aristo/aristo_init/rocks_db/rdb_init.nim
+++ b/nimbus/db/aristo/aristo_init/rocks_db/rdb_init.nim
@@ -231,11 +231,11 @@ proc reinit*(
   ok guestCols
 
 
-proc destroy*(rdb: var RdbInst; flush: bool) =
+proc destroy*(rdb: var RdbInst; eradicate: bool) =
   ## Destructor
   rdb.baseDb.close()
 
-  if flush:
+  if eradicate:
     try:
       rdb.dataDir.removeDir
 
diff --git a/nimbus/db/core_db/backend/aristo_db.nim b/nimbus/db/core_db/backend/aristo_db.nim
index 43ce88abd..c9a483924 100644
--- a/nimbus/db/core_db/backend/aristo_db.nim
+++ b/nimbus/db/core_db/backend/aristo_db.nim
@@ -143,9 +143,9 @@ proc baseMethods(db: AristoCoreDbRef): CoreDbBaseFns =
     ok()
 
   CoreDbBaseFns(
-    destroyFn: proc(flush: bool) =
-      aBase.destroy(flush)
-      kBase.destroy(flush),
+    destroyFn: proc(eradicate: bool) =
+      aBase.destroy(eradicate)
+      kBase.destroy(eradicate),
 
     levelFn: proc(): int =
       aBase.getLevel,
diff --git a/nimbus/db/core_db/backend/aristo_db/handlers_aristo.nim b/nimbus/db/core_db/backend/aristo_db/handlers_aristo.nim
index d59621388..ea7c0f861 100644
--- a/nimbus/db/core_db/backend/aristo_db/handlers_aristo.nim
+++ b/nimbus/db/core_db/backend/aristo_db/handlers_aristo.nim
@@ -367,8 +367,8 @@ proc accMethods(cAcc: AristoCoreDxAccRef): CoreDbAccFns =
       return err(rc.error.toError(base, info))
     ok()
 
-  proc accStoFlush(address: EthAddress): CoreDbRc[void] =
-    const info = "stoFlushFn()"
+  proc accStoDelete(address: EthAddress): CoreDbRc[void] =
+    const info = "stoDeleteFn()"
 
     let
       key = address.keccakHash.data
@@ -405,8 +405,8 @@ proc accMethods(cAcc: AristoCoreDxAccRef): CoreDbAccFns =
     deleteFn: proc(address: EthAddress): CoreDbRc[void] =
       accDelete(address),
 
-    stoFlushFn: proc(address: EthAddress): CoreDbRc[void] =
-      accStoFlush(address),
+    stoDeleteFn: proc(address: EthAddress): CoreDbRc[void] =
+      accStoDelete(address),
 
     mergeFn: proc(acc: CoreDbAccount): CoreDbRc[void] =
       accMerge(acc),
@@ -702,8 +702,8 @@ proc persistent*(
 # Public constructors and related
 # ------------------------------------------------------------------------------
 
-proc destroy*(base: AristoBaseRef; flush: bool) =
-  base.api.finish(base.ctx.mpt, flush)
+proc destroy*(base: AristoBaseRef; eradicate: bool) =
+  base.api.finish(base.ctx.mpt, eradicate)
 
 
 func init*(T: type AristoBaseRef; db: CoreDbRef; adb: AristoDbRef): T =
diff --git a/nimbus/db/core_db/backend/aristo_db/handlers_kvt.nim b/nimbus/db/core_db/backend/aristo_db/handlers_kvt.nim
index 6b7d00347..71816d753 100644
--- a/nimbus/db/core_db/backend/aristo_db/handlers_kvt.nim
+++ b/nimbus/db/core_db/backend/aristo_db/handlers_kvt.nim
@@ -223,8 +223,8 @@ proc newKvtHandler*(
     ok(base.cache)
 
 
-proc destroy*(base: KvtBaseRef; flush: bool) =
-  base.api.finish(base.kdb, flush)  # Close descriptor
+proc destroy*(base: KvtBaseRef; eradicate: bool) =
+  base.api.finish(base.kdb, eradicate)  # Close descriptor
 
 
 func init*(T: type KvtBaseRef; db: CoreDbRef; kdb: KvtDbRef): T =
diff --git a/nimbus/db/core_db/backend/aristo_db/handlers_trace.nim b/nimbus/db/core_db/backend/aristo_db/handlers_trace.nim
index 9f41e397e..c042e72dd 100644
--- a/nimbus/db/core_db/backend/aristo_db/handlers_trace.nim
+++ b/nimbus/db/core_db/backend/aristo_db/handlers_trace.nim
@@ -719,7 +719,7 @@ proc traceRecorder(
       # Delete from DB
       api.delTree(mpt, root, accPath).isOkOr:
         when EnableDebugLog:
-          debug logTxt, level, flags, key, error
+          debug logTxt, level, flags, error
         return err(error)
 
       # Update journal
diff --git a/nimbus/db/core_db/backend/aristo_rocksdb.nim b/nimbus/db/core_db/backend/aristo_rocksdb.nim
index 89b391092..7c9d161ec 100644
--- a/nimbus/db/core_db/backend/aristo_rocksdb.nim
+++ b/nimbus/db/core_db/backend/aristo_rocksdb.nim
@@ -48,7 +48,7 @@ proc newAristoRocksDbCoreDbRef*(path: string, opts: DbOptions): CoreDbRef =
   AristoDbRocks.create(kdb, adb)
 
 proc newAristoDualRocksDbCoreDbRef*(path: string, opts: DbOptions): CoreDbRef =
-  ## This is mainly for debugging. The KVT is run on a completely separate
+  ## This is only for debugging. The KVT is run on a completely separate
   ## database backend.
   let
     adb = AristoDbRef.init(use_ari.RdbBackendRef, path, opts).valueOr:
diff --git a/nimbus/db/core_db/base.nim b/nimbus/db/core_db/base.nim
index e4dab1370..7ac50e4e6 100644
--- a/nimbus/db/core_db/base.nim
+++ b/nimbus/db/core_db/base.nim
@@ -20,9 +20,6 @@ from ../aristo
   import EmptyBlob, PayloadRef, isValid
 
 const
-  ProvideLegacyAPI = false
-    ## Enable legacy API. For now everybody would want this enabled.
-
   EnableApiTracking = false
     ## When enabled, functions using this tracking facility need to import
     ## `chronicles`, as well. Tracking is enabled by setting `true` the flags
@@ -61,19 +58,9 @@ export
   PayloadRef
 
 const
-  CoreDbProvideLegacyAPI* = ProvideLegacyAPI
   CoreDbEnableApiTracking* = EnableApiTracking
   CoreDbEnableApiProfiling* = EnableApiTracking and EnableApiProfiling
 
-when ProvideLegacyAPI:
-  import
-    std/typetraits
-  type
-    TxWrapperApiError* = object of CoreDbApiError
-      ## For re-routing exception on tx/action template
-  export
-    CoreDbKvtRef, CoreDbMptRef, CoreDbPhkRef, CoreDbTxRef, CoreDbCaptRef
-
 when AutoValidateDescriptors:
   import ./base/validate
 
@@ -106,35 +93,6 @@ when EnableApiTracking:
   proc `$`(v: CoreDbColRef): string = v.toStr
   proc `$`(h: Hash256): string = h.toStr
 
-when ProvideLegacyAPI:
-  when EnableApiTracking:
-    proc `$`(k: CoreDbKvtRef): string = k.toStr
-
-  template setTrackLegaApi(
-      w: CoreDbApiTrackRef;
-      s: static[CoreDbFnInx];
-      code: untyped;
-        ) =
-    ## Template with code section that will be discarded if logging is
-    ## disabled at compile time when `EnableApiTracking` is `false`.
-    when EnableApiTracking:
-      w.beginLegaApi(s)
-      code
-    const api {.inject,used.} = s
-
-  template setTrackLegaApi*(
-      w: CoreDbApiTrackRef;
-      s: static[CoreDbFnInx];
-        ) =
-    w.setTrackLegaApi(s):
-      discard
-
-  template ifTrackLegaApi*(w: CoreDbApiTrackRef; code: untyped) =
-    when EnableApiTracking:
-      w.endLegaApiIf:
-        code
-
-
 template setTrackNewApi(
     w: CoreDxApiTrackRef;
     s: static[CoreDbFnInx];
@@ -286,16 +244,16 @@ proc backend*(dsc: CoreDxKvtRef | CoreDxMptRef): auto =
   result = dsc.methods.backendFn()
   dsc.ifTrackNewApi: debug newApiTxt, api, elapsed
 
-proc finish*(db: CoreDbRef; flush = false) =
-  ## Database destructor. If the argument `flush` is set `false`, the database
-  ## is left as-is and only the in-memory handlers are cleaned up.
+proc finish*(db: CoreDbRef; eradicate = false) =
+  ## Database destructor. If the argument `eradicate` is set `false`, the
+  ## database is left as-is and only the in-memory handlers are cleaned up.
   ##
   ## Otherwise the destructor is allowed to remove the database. This feature
   ## depends on the backend database. Currently, only the `AristoDbRocks` type
   ## backend removes the database on `true`.
   ##
   db.setTrackNewApi BaseFinishFn
-  db.methods.destroyFn flush
+  db.methods.destroyFn eradicate
   db.ifTrackNewApi: debug newApiTxt, api, elapsed
 
 proc `$$`*(e: CoreDbErrorRef): string =
@@ -746,7 +704,7 @@ proc delete*(acc: CoreDxAccRef; address: EthAddress): CoreDbRc[void] =
   result = acc.methods.deleteFn address
   acc.ifTrackNewApi: debug newApiTxt, api, elapsed, address, result
 
-proc stoFlush*(acc: CoreDxAccRef; address: EthAddress): CoreDbRc[void] =
+proc stoDelete*(acc: CoreDxAccRef; address: EthAddress): CoreDbRc[void] =
   ## Recursively delete all data elements from the storage trie associated to
   ## the account identified by the argument `address`. After successful run,
   ## the storage trie will be empty.
@@ -757,8 +715,8 @@ proc stoFlush*(acc: CoreDxAccRef; address: EthAddress): CoreDbRc[void] =
   ##   shared by several accounts whereas they are unique on the `Aristo`
   ##   backend.
   ##
-  acc.setTrackNewApi AccStoFlushFn
-  result = acc.methods.stoFlushFn address
+  acc.setTrackNewApi AccStoDeleteFn
+  result = acc.methods.stoDeleteFn address
   acc.ifTrackNewApi: debug newApiTxt, api, elapsed, address, result
 
 
@@ -959,206 +917,6 @@ proc forget*(cp: CoreDxCaptRef) =
   cp.methods.forgetFn()
   cp.ifTrackNewApi: debug newApiTxt, api, elapsed
 
-# ------------------------------------------------------------------------------
-# Public methods, legacy API
-# ------------------------------------------------------------------------------
-
-when ProvideLegacyAPI:
-
-  proc parent*[T: CoreDbKvtRef | CoreDbMptRef | CoreDbPhkRef |
-                  CoreDbTxRef | CoreDbCaptRef](
-      cld: T): CoreDbRef =
-    ## Getter, common method for all sub-modules
-    result = cld.distinctBase.parent
-
-  # ----------------
-
-  proc kvt*(db: CoreDbRef): CoreDbKvtRef =
-    ## Legacy pseudo constructor, see `toKvt()` for production constructor
-    db.setTrackLegaApi LegaNewKvtFn
-    result = db.newKvt().CoreDbKvtRef
-    db.ifTrackLegaApi: debug legaApiTxt, api, elapsed, result
-
-  proc get*(kvt: CoreDbKvtRef; key: openArray[byte]): Blob =
-    kvt.setTrackLegaApi LegaKvtGetFn
-    result = kvt.distinctBase.getOrEmpty(key).expect $api
-    kvt.ifTrackLegaApi: debug legaApiTxt, api, elapsed, key=key.toStr, result
-
-  proc del*(kvt: CoreDbKvtRef; key: openArray[byte]): void =
-    kvt.setTrackLegaApi LegaKvtDelFn
-    kvt.distinctBase.del(key).expect $api
-    kvt.ifTrackLegaApi: debug legaApiTxt, api, elapsed, key=key.toStr
-
-  proc put*(kvt: CoreDbKvtRef; key: openArray[byte]; val: openArray[byte]) =
-    kvt.setTrackLegaApi LegaKvtPutFn
-    kvt.distinctBase.parent.newKvt().put(key, val).expect $api
-    kvt.ifTrackLegaApi:
-      debug legaApiTxt, api, elapsed, key=key.toStr, val=val.toLenStr
-
-  proc contains*(kvt: CoreDbKvtRef; key: openArray[byte]): bool =
-    kvt.setTrackLegaApi LegaKvtContainsFn
-    result = kvt.distinctBase.hasKey(key).expect $api
-    kvt.ifTrackLegaApi: debug legaApiTxt, api, elapsed, key=key.toStr, result
-
-  # ----------------
-
-  proc toMpt*(phk: CoreDbPhkRef): CoreDbMptRef =
-    phk.setTrackLegaApi LegaToMptFn
-    result = phk.distinctBase.toMpt.CoreDbMptRef
-    phk.ifTrackLegaApi: debug legaApiTxt, api, elapsed
-
-  proc mptPrune*(db: CoreDbRef; root: Hash256): CoreDbMptRef =
-    db.setTrackLegaApi LegaNewMptFn
-    let
-      trie = db.ctx.methods.newColFn(
-          CtGeneric, root, Opt.none(EthAddress)).valueOr:
-        raiseAssert error.prettyText() & ": " & $api
-      mpt = db.ctx.getMpt(trie).valueOr:
-        raiseAssert error.prettyText() & ": " & $api
-    result = mpt.CoreDbMptRef
-    db.ifTrackLegaApi: debug legaApiTxt, api, elapsed, root
-
-  proc mptPrune*(db: CoreDbRef): CoreDbMptRef =
-    db.setTrackLegaApi LegaNewMptFn
-    result = db.ctx.getMpt(CtGeneric, Opt.none(EthAddress)).CoreDbMptRef
-    db.ifTrackLegaApi: debug legaApiTxt, api, elapsed
-
-  # ----------------
-
-  proc toPhk*(mpt: CoreDbMptRef): CoreDbPhkRef =
-    mpt.setTrackLegaApi LegaToPhkFn
-    result = mpt.distinctBase.toPhk.CoreDbPhkRef
-    mpt.ifTrackLegaApi: debug legaApiTxt, api, elapsed
-
-  proc phkPrune*(db: CoreDbRef; root: Hash256): CoreDbPhkRef =
-    db.setTrackLegaApi LegaNewPhkFn
-    let
-      trie = db.ctx.methods.newColFn(
-          CtGeneric, root, Opt.none(EthAddress)).valueOr:
-        raiseAssert error.prettyText() & ": " & $api
-      phk = db.ctx.getMpt(trie).valueOr:
-        raiseAssert error.prettyText() & ": " & $api
-    result = phk.toCoreDxPhkRef.CoreDbPhkRef
-    db.ifTrackLegaApi: debug legaApiTxt, api, elapsed, root
-
-  proc phkPrune*(db: CoreDbRef): CoreDbPhkRef =
-    db.setTrackLegaApi LegaNewPhkFn
-    result = db.ctx.getMpt(
-      CtGeneric, Opt.none(EthAddress)).toCoreDxPhkRef.CoreDbPhkRef
-    db.ifTrackLegaApi: debug legaApiTxt, api, elapsed
-
-  # ----------------
-
-  proc get*(mpt: CoreDbMptRef; key: openArray[byte]): Blob =
-    mpt.setTrackLegaApi LegaMptGetFn
-    result = mpt.distinctBase.fetchOrEmpty(key).expect $api
-    mpt.ifTrackLegaApi: debug legaApiTxt, api, elapsed, key=key.toStr, result
-
-  proc get*(phk: CoreDbPhkRef; key: openArray[byte]): Blob =
-    phk.setTrackLegaApi LegaPhkGetFn
-    result = phk.distinctBase.fetchOrEmpty(key).expect $api
-    phk.ifTrackLegaApi:
-      debug legaApiTxt, api, elapsed, key=key.toStr, result
-
-
-  proc del*(mpt: CoreDbMptRef; key: openArray[byte]) =
-    mpt.setTrackLegaApi LegaMptDelFn
-    mpt.distinctBase.delete(key).expect $api
-    mpt.ifTrackLegaApi: debug legaApiTxt, api, elapsed, key=key.toStr
-
-  proc del*(phk: CoreDbPhkRef; key: openArray[byte]) =
-    phk.setTrackLegaApi LegaPhkDelFn
-    phk.distinctBase.delete(key).expect $api
-    phk.ifTrackLegaApi: debug legaApiTxt, api, elapsed, key=key.toStr
-
-
-  proc put*(mpt: CoreDbMptRef; key: openArray[byte]; val: openArray[byte]) =
-    mpt.setTrackLegaApi LegaMptPutFn
-    mpt.distinctBase.merge(key, val).expect $api
-    mpt.ifTrackLegaApi:
-      debug legaApiTxt, api, elapsed, key=key.toStr, val=val.toLenStr
-
-  proc put*(phk: CoreDbPhkRef; key: openArray[byte]; val: openArray[byte]) =
-    phk.setTrackLegaApi LegaPhkPutFn
-    phk.distinctBase.merge(key, val).expect $api
-    phk.ifTrackLegaApi:
-      debug legaApiTxt, api, elapsed, key=key.toStr, val=val.toLenStr
-
-
-  proc contains*(mpt: CoreDbMptRef; key: openArray[byte]): bool =
-    mpt.setTrackLegaApi LegaMptContainsFn
-    result = mpt.distinctBase.hasPath(key).expect $api
-    mpt.ifTrackLegaApi: debug legaApiTxt, api, elapsed, key=key.toStr, result
-
-  proc contains*(phk: CoreDbPhkRef; key: openArray[byte]): bool =
-    phk.setTrackLegaApi LegaPhkContainsFn
-    result = phk.distinctBase.hasPath(key).expect $api
-    phk.ifTrackLegaApi: debug legaApiTxt, api, elapsed, key=key.toStr, result
-
-
-  proc rootHash*(mpt: CoreDbMptRef): Hash256 =
-    mpt.setTrackLegaApi LegaMptRootHashFn
-    result = mpt.distinctBase.methods.getColFn().state.valueOr:
-      raiseAssert error.prettyText() & ": " & $api
-    mpt.ifTrackLegaApi: debug legaApiTxt, api, elapsed, result
-
-  proc rootHash*(phk: CoreDbPhkRef): Hash256 =
-    phk.setTrackLegaApi LegaPhkRootHashFn
-    result = phk.distinctBase.methods.getColFn().state.valueOr:
-      raiseAssert error.prettyText() & ": " & $api
-    phk.ifTrackLegaApi: debug legaApiTxt, api, elapsed, result
-
-  # ----------------
-
-  proc beginTransaction*(db: CoreDbRef): CoreDbTxRef =
-    db.setTrackLegaApi LegaBeginTxFn
-    result = db.distinctBase.methods.beginFn().CoreDbTxRef
-    db.ifTrackLegaApi:
-      debug legaApiTxt, api, elapsed, newLevel=db.methods.levelFn()
-
-  proc commit*(tx: CoreDbTxRef, applyDeletes = true) =
-    tx.setTrackLegaApi LegaTxCommitFn:
-      let prvLevel {.used.} = tx.distinctBase.methods.levelFn()
-    tx.distinctBase.commit()
-    tx.ifTrackLegaApi: debug legaApiTxt, api, elapsed, prvLevel
-
-  proc rollback*(tx: CoreDbTxRef) =
-    tx.setTrackLegaApi LegaTxCommitFn:
-      let prvLevel {.used.} = tx.distinctBase.methods.levelFn()
-    tx.distinctBase.rollback()
-    tx.ifTrackLegaApi: debug legaApiTxt, api, elapsed, prvLevel
-
-  proc dispose*(tx: CoreDbTxRef) =
-    tx.setTrackLegaApi LegaTxDisposeFn:
-      let prvLevel {.used.} = tx.distinctBase.methods.levelFn()
-    tx.distinctBase.dispose()
-    tx.ifTrackLegaApi: debug legaApiTxt, api, elapsed, prvLevel
-
-  # ----------------
-
-  proc capture*(
-      db: CoreDbRef;
-      flags: set[CoreDbCaptFlags] = {};
-        ): CoreDbCaptRef =
-    db.setTrackLegaApi LegaCaptureFn
-    result = db.newCapture(flags).expect($api).CoreDbCaptRef
-    db.ifTrackLegaApi: debug legaApiTxt, api, elapsed
-
-  proc recorder*(cp: CoreDbCaptRef): CoreDbRef =
-    cp.setTrackLegaApi LegaCptRecorderFn
-    result = cp.distinctBase.recorder()
-    cp.ifTrackLegaApi: debug legaApiTxt, api, elapsed
-
-  proc logDb*(cp: CoreDbCaptRef): TableRef[Blob,Blob] =
-    cp.setTrackLegaApi LegaCptLogDbFn
-    result = cp.distinctBase.logDb()
-    cp.ifTrackLegaApi: debug legaApiTxt, api, elapsed
-
-  proc flags*(cp: CoreDbCaptRef): set[CoreDbCaptFlags] =
-    cp.setTrackLegaApi LegaCptFlagsFn
-    result = cp.distinctBase.flags()
-    cp.ifTrackLegaApi: debug legaApiTxt, api, elapsed, result
-
 # ------------------------------------------------------------------------------
 # End
 # ------------------------------------------------------------------------------
diff --git a/nimbus/db/core_db/base/api_tracking.nim b/nimbus/db/core_db/base/api_tracking.nim
index e9c625b39..273c388fa 100644
--- a/nimbus/db/core_db/base/api_tracking.nim
+++ b/nimbus/db/core_db/base/api_tracking.nim
@@ -19,10 +19,6 @@ import
   ./base_desc
 
 type
-  CoreDbApiTrackRef* =
-    CoreDbRef | CoreDbKvtRef | CoreDbMptRef | CoreDbPhkRef |
-    CoreDbTxRef | CoreDbCaptRef
-
   CoreDxApiTrackRef* =
     CoreDbRef | CoreDxKvtRef | CoreDbColRef |
     CoreDbCtxRef | CoreDxMptRef | CoreDxPhkRef | CoreDxAccRef |
@@ -39,7 +35,7 @@ type
     AccHasPathFn        = "acc/hasPath"
     AccMergeFn          = "acc/merge"
     AccGetMptFn         = "acc/getMpt"
-    AccStoFlushFn       = "acc/stoFlush"
+    AccStoDeleteFn      = "acc/stoDelete"
     AccToMptFn          = "acc/toMpt"
 
     AnyBackendFn        = "any/backend"
@@ -78,44 +74,6 @@ type
     KvtPairsIt          = "kvt/pairs"
     KvtPutFn            = "kvt/put"
 
-    LegaBeginTxFn       = "lega/beginTransaction"
-    LegaCaptureFn       = "lega/cpt/capture"
-    LegaCptFlagsFn      = "lega/cpt/flags"
-    LegaCptLogDbFn      = "lega/cpt/logDb"
-    LegaCptRecorderFn   = "lega/cpt/recorder"
-
-    LegaKvtContainsFn   = "lega/kvt/contains"
-    LegaKvtDelFn        = "lega/kvt/del"
-    LegaKvtGetFn        = "lega/kvt/get"
-    LegaKvtPairsIt      = "lega/kvt/pairs"
-    LegaKvtPutFn        = "lega/kvt/put"
-
-    LegaMptContainsFn   = "lega/mpt/contains"
-    LegaMptDelFn        = "lega/mpt/del"
-    LegaMptGetFn        = "lega/mpt/get"
-    LegaMptPutFn        = "lega/mpt/put"
-    LegaMptRootHashFn   = "lega/mpt/rootHash"
-    LegaMptPairsIt      = "lega/mpt/pairs"
-    LegaMptReplicateIt  = "lega/mpt/replicate"
-
-    LegaNewKvtFn        = "lega/kvt"
-    LegaNewMptFn        = "lega/mptPrune"
-    LegaNewPhkFn        = "lega/phkPrune"
-
-    LegaPhkContainsFn   = "lega/phk/contains"
-    LegaPhkDelFn        = "lega/phk/del"
-    LegaPhkGetFn        = "lega/phk/get"
-    LegaPhkPutFn        = "lega/phk/put"
-    LegaPhkRootHashFn   = "lega/phk/rootHash"
-
-    LegaToMptFn         = "lega/phk/toMpt"
-    LegaToPhkFn         = "lega/mpt/toPhk"
-
-    LegaTxCommitFn      = "lega/commit"
-    LegaTxDisposeFn     = "lega/dispose"
-    LegaTxRollbackFn    = "lega/rollback"
-    LegaTxSaveDisposeFn = "lega/safeDispose"
-
     MptDeleteFn         = "mpt/delete"
     MptFetchFn          = "mpt/fetch"
     MptFetchOrEmptyFn   = "mpt/fetchOrEmpty"
@@ -165,9 +123,6 @@ proc toStr*(p: CoreDbColRef): string =
     (a,b) = if 0 < w.len and w[0] == '(': ("","") else: ("(",")")
   "Col" & a & w & b
 
-func toStr*(w: CoreDbKvtRef): string =
-  if w.distinctBase.isNil: "kvt(nil)" else: "kvt"
-
 func toLenStr*(w: openArray[byte]): string =
   if 0 < w.len and w.len < 5: "<" & w.oaToStr & ">"
   else: "openArray[" & $w.len & "]"
@@ -219,38 +174,6 @@ proc toStr*(rc: CoreDbRc[CoreDxAccRef]): string = rc.toStr "acc"
 func toStr*(ela: Duration): string =
   aristo_profile.toStr(ela)
 
-# ------------------------------------------------------------------------------
-# Public legacy API logging framework
-# ------------------------------------------------------------------------------
-
-template beginLegaApi*(w: CoreDbApiTrackRef; s: static[CoreDbFnInx]) =
-  when typeof(w) is CoreDbRef:
-    let db = w
-  else:
-    let db = w.distinctBase.parent
-  # Prevent from cascaded logging
-  let save = db.trackNewApi
-  db.trackNewApi = false
-  defer: db.trackNewApi = save
-
-  when CoreDbEnableApiProfiling:
-    const blaCtx {.inject.} = s       # Local use only
-  let blaStart {.inject.} = getTime() # Local use only
-
-template endLegaApiIf*(w: CoreDbApiTrackRef; code: untyped) =
-  block:
-    when typeof(w) is CoreDbRef:
-      let db = w
-    else:
-      let db = w.distinctBase.parent
-    when CoreDbEnableApiProfiling:
-      let elapsed {.inject,used.} = getTime() - blaStart
-      aristo_profile.update(db.profTab, blaCtx.ord, elapsed)
-    if db.trackLegaApi:
-      when not CoreDbEnableApiProfiling: # otherwise use variable above
-        let elapsed {.inject,used.} = getTime() - blaStart
-      code
-
 # ------------------------------------------------------------------------------
 # Public new API logging framework
 # ------------------------------------------------------------------------------
diff --git a/nimbus/db/core_db/base/base_desc.nim b/nimbus/db/core_db/base/base_desc.nim
index f342267f9..58c034912 100644
--- a/nimbus/db/core_db/base/base_desc.nim
+++ b/nimbus/db/core_db/base/base_desc.nim
@@ -27,19 +27,12 @@ type
     Ooops
     AristoDbMemory            ## Memory backend emulator
     AristoDbRocks             ## RocksDB backend
-    AristoDbDualRocks         ## Dual RocksDB backends for `Kvt` and `Aristo`
     AristoDbVoid              ## No backend
 
 const
   CoreDbPersistentTypes* = {AristoDbRocks}
 
 type
-  CoreDbKvtRef*  = distinct CoreDxKvtRef  # Legacy descriptor
-  CoreDbMptRef*  = distinct CoreDxMptRef  # Legacy descriptor
-  CoreDbPhkRef*  = distinct CoreDxPhkRef  # Legacy descriptor
-  CoreDbTxRef*   = distinct CoreDxTxRef   # Legacy descriptor
-  CoreDbCaptRef* = distinct CoreDxCaptRef # Legacy descriptor
-
   CoreDbProfListRef* = AristoDbProfListRef
     ## Borrowed from `aristo_profile`, only used in profiling mode
 
@@ -96,7 +89,7 @@ type
   # --------------------------------------------------
   # Sub-descriptor: Misc methods for main descriptor
   # --------------------------------------------------
-  CoreDbBaseDestroyFn* = proc(flush = true) {.noRaise.}
+  CoreDbBaseDestroyFn* = proc(eradicate = true) {.noRaise.}
   CoreDbBaseColStateFn* = proc(
     col: CoreDbColRef): CoreDbRc[Hash256] {.noRaise.}
   CoreDbBaseColPrintFn* = proc(vid: CoreDbColRef): string {.noRaise.}
@@ -214,7 +207,7 @@ type
   CoreDbAccGetMptFn* = proc(): CoreDbRc[CoreDxMptRef] {.noRaise.}
   CoreDbAccFetchFn* = proc(k: EthAddress): CoreDbRc[CoreDbAccount] {.noRaise.}
   CoreDbAccDeleteFn* = proc(k: EthAddress): CoreDbRc[void] {.noRaise.}
-  CoreDbAccStoFlushFn* = proc(k: EthAddress): CoreDbRc[void] {.noRaise.}
+  CoreDbAccStoDeleteFn* = proc(k: EthAddress): CoreDbRc[void] {.noRaise.}
   CoreDbAccMergeFn* = proc(v: CoreDbAccount): CoreDbRc[void] {.noRaise.}
   CoreDbAccHasPathFn* = proc(k: EthAddress): CoreDbRc[bool] {.noRaise.}
   CoreDbAccGetColFn* = proc(): CoreDbColRef {.noRaise.}
@@ -225,7 +218,7 @@ type
     getMptFn*:     CoreDbAccGetMptFn
     fetchFn*:      CoreDbAccFetchFn
     deleteFn*:     CoreDbAccDeleteFn
-    stoFlushFn*:   CoreDbAccStoFlushFn
+    stoDeleteFn*:  CoreDbAccStoDeleteFn
     mergeFn*:      CoreDbAccMergeFn
     hasPathFn*:    CoreDbAccHasPathFn
     getColFn*:     CoreDbAccGetColFn
diff --git a/nimbus/db/core_db/base/validate.nim b/nimbus/db/core_db/base/validate.nim
index 77b164641..23f848668 100644
--- a/nimbus/db/core_db/base/validate.nim
+++ b/nimbus/db/core_db/base/validate.nim
@@ -67,7 +67,7 @@ proc validateMethodsDesc(fns: CoreDbAccFns) =
   doAssert not fns.getMptFn.isNil
   doAssert not fns.fetchFn.isNil
   doAssert not fns.deleteFn.isNil
-  doAssert not fns.stoFlushFn.isNil
+  doAssert not fns.stoDeleteFn.isNil
   doAssert not fns.mergeFn.isNil
   doAssert not fns.hasPathFn.isNil
   doAssert not fns.getColFn.isNil
diff --git a/nimbus/db/core_db/base_iterators.nim b/nimbus/db/core_db/base_iterators.nim
index d7a14ab06..89da113b3 100644
--- a/nimbus/db/core_db/base_iterators.nim
+++ b/nimbus/db/core_db/base_iterators.nim
@@ -20,13 +20,8 @@ import
 when CoreDbEnableApiTracking:
   import chronicles
 
-const
-  ProvideLegacyAPI = CoreDbProvideLegacyAPI
-
-when ProvideLegacyAPI and CoreDbEnableApiTracking:
   const
     logTxt = "CoreDb/it "
-    legaApiTxt = logTxt & "legacy API"
     newApiTxt = logTxt & "API"
 
 # Annotation helper(s)
@@ -82,25 +77,6 @@ iterator replicate*(mpt: CoreDxMptRef): (Blob, Blob) {.apiRaise.} =
     let trie = mpt.methods.getColFn()
     debug newApiTxt, api, elapsed, trie
 
-when ProvideLegacyAPI:
-
-  iterator pairs*(kvt: CoreDbKvtRef): (Blob, Blob) {.apiRaise.} =
-    kvt.setTrackLegaApi LegaKvtPairsIt
-    for k,v in kvt.distinctBase.pairs(): yield (k,v)
-    kvt.ifTrackLegaApi: debug legaApiTxt, api, elapsed
-
-  iterator pairs*(mpt: CoreDbMptRef): (Blob, Blob) =
-    ## Trie traversal, not supported for `CoreDbPhkRef`
-    mpt.setTrackLegaApi LegaMptPairsIt
-    for k,v in mpt.distinctBase.pairs(): yield (k,v)
-    mpt.ifTrackLegaApi: debug legaApiTxt, api, elapsed
-
-  iterator replicate*(mpt: CoreDbMptRef): (Blob, Blob) {.apiRaise.} =
-    ## Low level trie dump, not supported for `CoreDbPhkRef`
-    mpt.setTrackLegaApi LegaMptReplicateIt
-    for k,v in mpt.distinctBase.replicate(): yield (k,v)
-    mpt.ifTrackLegaApi: debug legaApiTxt, api, elapsed
-
 # ------------------------------------------------------------------------------
 # End
 # ------------------------------------------------------------------------------
diff --git a/nimbus/db/core_db/base_iterators_persistent.nim b/nimbus/db/core_db/base_iterators_persistent.nim
index dd3484d5c..e1c451e06 100644
--- a/nimbus/db/core_db/base_iterators_persistent.nim
+++ b/nimbus/db/core_db/base_iterators_persistent.nim
@@ -20,13 +20,8 @@ import
 when CoreDbEnableApiTracking:
   import chronicles
 
-const
-  ProvideLegacyAPI = CoreDbProvideLegacyAPI
-
-when ProvideLegacyAPI and CoreDbEnableApiTracking:
   const
     logTxt = "CoreDb/itp "
-    legaApiTxt = logTxt & "legacy API"
     newApiTxt = logTxt & "API"
 
 # Annotation helper(s)
@@ -56,14 +51,6 @@ iterator replicatePersistent*(mpt: CoreDxMptRef): (Blob, Blob) {.rlpRaise.} =
     let trie = mpt.methods.getColFn()
     debug newApiTxt, api, elapsed, trie
 
-when ProvideLegacyAPI:
-
-  iterator replicatePersistent*(mpt: CoreDbMptRef): (Blob, Blob) {.rlpRaise.} =
-    ## Low level trie dump, not supported for `CoreDbPhkRef`
-    mpt.setTrackLegaApi LegaMptReplicateIt
-    for k,v in mpt.distinctBase.replicatePersistent(): yield (k,v)
-    mpt.ifTrackLegaApi: debug legaApiTxt, api, elapsed
-
 # ------------------------------------------------------------------------------
 # End
 # ------------------------------------------------------------------------------
diff --git a/nimbus/db/core_db/core_apps_newapi.nim b/nimbus/db/core_db/core_apps.nim
similarity index 100%
rename from nimbus/db/core_db/core_apps_newapi.nim
rename to nimbus/db/core_db/core_apps.nim
diff --git a/nimbus/db/core_db/memory_only.nim b/nimbus/db/core_db/memory_only.nim
index c5a6af893..43e888917 100644
--- a/nimbus/db/core_db/memory_only.nim
+++ b/nimbus/db/core_db/memory_only.nim
@@ -13,14 +13,11 @@
 import
   eth/common,
   ../aristo,
-  ./backend/aristo_db
+  ./backend/aristo_db,
+  "."/[base_iterators, core_apps]
 
-import
-  ./core_apps_newapi as core_apps
 import
   ./base except bless
-import
-  ./base_iterators
 
 export
   EmptyBlob,
diff --git a/nimbus/db/core_db/persistent.nim b/nimbus/db/core_db/persistent.nim
index 9700154af..c2d2a4092 100644
--- a/nimbus/db/core_db/persistent.nim
+++ b/nimbus/db/core_db/persistent.nim
@@ -42,17 +42,9 @@ proc newCoreDbRef*(
   ## The production database type is `AristoDbRocks` which uses a single
   ## `RocksDb` backend for both, `Aristo` and `KVT`.
   ##
-  ## For debugging, there is the `AristoDbDualRocks` database with split
-  ## backends for `Aristo` and `KVT`. This database is not compatible with
-  ## `AristoDbRocks` so it cannot be reliably switched between both versions
-  ## with consecutive sessions.
-  ##
   when dbType == AristoDbRocks:
     newAristoRocksDbCoreDbRef path, opts
 
-  elif dbType == AristoDbDualRocks:
-    newAristoDualRocksDbCoreDbRef path, opts
-
   else:
     {.error: "Unsupported dbType for persistent newCoreDbRef()".}
 
diff --git a/nimbus/db/kvt/kvt_api.nim b/nimbus/db/kvt/kvt_api.nim
index 9eeec0bf7..eb939fde4 100644
--- a/nimbus/db/kvt/kvt_api.nim
+++ b/nimbus/db/kvt/kvt_api.nim
@@ -44,7 +44,7 @@ type
   KvtApiCommitFn* = proc(tx: KvtTxRef): Result[void,KvtError] {.noRaise.}
   KvtApiDelFn* = proc(db: KvtDbRef,
     key: openArray[byte]): Result[void,KvtError] {.noRaise.}
-  KvtApiFinishFn* = proc(db: KvtDbRef, flush = false) {.noRaise.}
+  KvtApiFinishFn* = proc(db: KvtDbRef, eradicate = false) {.noRaise.}
   KvtApiForgetFn* = proc(db: KvtDbRef): Result[void,KvtError] {.noRaise.}
   KvtApiForkTxFn* = proc(db: KvtDbRef,
     backLevel: int): Result[KvtDbRef,KvtError] {.noRaise.}
diff --git a/nimbus/db/kvt/kvt_desc/desc_backend.nim b/nimbus/db/kvt/kvt_desc/desc_backend.nim
index 4b01f89ff..541981b90 100644
--- a/nimbus/db/kvt/kvt_desc/desc_backend.nim
+++ b/nimbus/db/kvt/kvt_desc/desc_backend.nim
@@ -47,11 +47,11 @@ type
   # -------------
 
   CloseFn* =
-    proc(flush: bool) {.gcsafe, raises: [].}
-      ## Generic destructor for the `Kvt DB` backend. The argument `flush`
+    proc(eradicate: bool) {.gcsafe, raises: [].}
+      ## Generic destructor for the `Kvt DB` backend. The argument `eradicate`
       ## indicates that a full database deletion is requested. If passed
       ## `false` the outcome might differ depending on the type of backend
-      ## (e.g. in-memory backends would flush on close.)
+      ## (e.g. in-memory backends would eradicate on close.)
 
   CanModFn* =
     proc(): Result[void,KvtError] {.gcsafe, raises: [].}
@@ -64,9 +64,10 @@ type
       ## This function stores a request function for the piggiback mode
       ## writing to the `Aristo` set of column families.
       ##
-      ## If used at all, this function would run `rocks_db.setWrReqTriggeredFn()()`
-      ## with a `KvtDbRef` type argument for `db`. This allows to run the `Kvt`
-      ## without linking to the rocksdb interface unless it is really needed.
+      ## If used at all, this function would run thee function closure
+      ## `rocks_db.setWrReqTriggeredFn()()` with a `KvtDbRef` type argument
+      ## for `db`. This allows to run the `Kvt` without linking to the
+      ## rocksdb interface unless it is really needed.
 
   # -------------
 
@@ -92,6 +93,7 @@ proc init*(trg: var BackendObj; src: BackendObj) =
   trg.putEndFn = src.putEndFn
   trg.closeFn = src.closeFn
   trg.canModFn = src.canModFn
+  trg.setWrReqFn = src.setWrReqFn
 
 # ------------------------------------------------------------------------------
 # End
diff --git a/nimbus/db/kvt/kvt_init/memory_only.nim b/nimbus/db/kvt/kvt_init/memory_only.nim
index 2a9fa7efb..bc61ed019 100644
--- a/nimbus/db/kvt/kvt_init/memory_only.nim
+++ b/nimbus/db/kvt/kvt_init/memory_only.nim
@@ -65,16 +65,14 @@ proc init*(
   KvtDbRef.init VoidBackendRef
  
 
-proc finish*(db: KvtDbRef; flush = false) =
-  ## Backend destructor. The argument `flush` indicates that a full database
-  ## deletion is requested. If set `false` the outcome might differ depending
-  ## on the type of backend (e.g. the `BackendMemory` backend will always
-  ## flush on close.)
-  ##
-  ## This distructor may be used on already *destructed* descriptors.
+proc finish*(db: KvtDbRef; eradicate = false) =
+  ## Backend destructor. The argument `eradicate` indicates that a full
+  ## database deletion is requested. If set `false` the outcome might differ
+  ## depending on the type of backend (e.g. the `BackendMemory` backend will
+  ## always eradicate on close.)
   ##
   if not db.backend.isNil:
-    db.backend.closeFn flush
+    db.backend.closeFn eradicate
   discard db.getCentre.forgetOthers()
 
 # ------------------------------------------------------------------------------
diff --git a/nimbus/db/kvt/kvt_init/rocks_db.nim b/nimbus/db/kvt/kvt_init/rocks_db.nim
index ba7902020..f8ff34d03 100644
--- a/nimbus/db/kvt/kvt_init/rocks_db.nim
+++ b/nimbus/db/kvt/kvt_init/rocks_db.nim
@@ -134,8 +134,8 @@ proc putEndFn(db: RdbBackendRef): PutEndFn =
 
 proc closeFn(db: RdbBackendRef): CloseFn =
   result =
-    proc(flush: bool) =
-      db.rdb.destroy(flush)
+    proc(eradicate: bool) =
+      db.rdb.destroy(eradicate)
 
 proc canModFn(db: RdbBackendRef): CanModFn =
   result =
@@ -186,7 +186,7 @@ proc putEndTriggeredFn(db: RdbBackendRef): PutEndFn =
 proc closeTriggeredFn(db: RdbBackendRef): CloseFn =
   ## Variant of `closeFn()` for piggyback write batch
   result =
-    proc(flush: bool) =
+    proc(eradicate: bool) =
       # Nothing to do here as we do not own the backend
       discard
 
diff --git a/nimbus/db/kvt/kvt_init/rocks_db/rdb_init.nim b/nimbus/db/kvt/kvt_init/rocks_db/rdb_init.nim
index 0b0365a3e..e3cacfc8e 100644
--- a/nimbus/db/kvt/kvt_init/rocks_db/rdb_init.nim
+++ b/nimbus/db/kvt/kvt_init/rocks_db/rdb_init.nim
@@ -28,9 +28,50 @@ import
 # ------------------------------------------------------------------------------
 
 proc getCFInitOptions(opts: DbOptions): ColFamilyOptionsRef =
-  result = defaultColFamilyOptions()
+ # TODO the configuration options below have not been tuned but are rather
+  #      based on gut feeling, guesses and by looking at other clients - it
+  #      would make sense to test different settings and combinations once the
+  #      data model itself has settled down as their optimal values will depend
+  #      on the shape of the data - it'll also be different per column family..
+  let cfOpts = defaultColFamilyOptions()
+
   if opts.writeBufferSize > 0:
-    result.setWriteBufferSize(opts.writeBufferSize)
+    cfOpts.setWriteBufferSize(opts.writeBufferSize)
+
+  # Without this option, the WAL might never get flushed since a small column
+  # family (like the admin CF) with only tiny writes might keep it open - this
+  # negatively affects startup times since the WAL is replayed on every startup.
+  # https://github.com/facebook/rocksdb/blob/af50823069818fc127438e39fef91d2486d6e76c/include/rocksdb/options.h#L719
+  # Flushing the oldest
+  let writeBufferSize =
+    if opts.writeBufferSize > 0:
+      opts.writeBufferSize
+    else:
+      64 * 1024 * 1024 # TODO read from rocksdb?
+
+  cfOpts.setMaxTotalWalSize(2 * writeBufferSize)
+
+  # When data is written to rocksdb, it is first put in an in-memory table
+  # whose index is a skip list. Since the mem table holds the most recent data,
+  # all reads must go through this skiplist which results in slow lookups for
+  # already-written data.
+  # We enable a bloom filter on the mem table to avoid this lookup in the cases
+  # where the data is actually on disk already (ie wasn't updated recently).
+  # TODO there's also a hashskiplist that has both a hash index and a skip list
+  #      which maybe could be used - uses more memory, requires a key prefix
+  #      extractor
+  cfOpts.setMemtableWholeKeyFiltering(true)
+  cfOpts.setMemtablePrefixBloomSizeRatio(0.1)
+
+  # LZ4 seems to cut database size to 2/3 roughly, at the time of writing
+  # Using it for the bottom-most level means it applies to 90% of data but
+  # delays compression until data has settled a bit, which seems like a
+  # reasonable tradeoff.
+  # TODO evaluate zstd compression with a trained dictionary
+  # https://github.com/facebook/rocksdb/wiki/Compression
+  cfOpts.setBottommostCompression(Compression.lz4Compression)
+
+  cfOpts
 
 
 proc getDbInitOptions(opts: DbOptions): DbOptionsRef =
@@ -107,12 +148,12 @@ proc init*(
   ok()
  
 
-proc destroy*(rdb: var RdbInst; flush: bool) =
+proc destroy*(rdb: var RdbInst; eradicate: bool) =
   ## Destructor (no need to do anything if piggybacked)
   if 0 < rdb.basePath.len:
     rdb.baseDb.close()
 
-    if flush:
+    if eradicate:
       try:
         rdb.dataDir.removeDir
 
diff --git a/nimbus/db/ledger/distinct_ledgers.nim b/nimbus/db/ledger/distinct_ledgers.nim
index b0a744859..02098003d 100644
--- a/nimbus/db/ledger/distinct_ledgers.nim
+++ b/nimbus/db/ledger/distinct_ledgers.nim
@@ -152,13 +152,13 @@ proc merge*(al: AccountLedger; account: CoreDbAccount) =
 proc freeStorage*(al: AccountLedger, eAddr: EthAddress) =
   const info = "AccountLedger/freeStorage()"
   # Flush associated storage trie
-  al.distinctBase.stoFlush(eAddr).isOkOr:
+  al.distinctBase.stoDelete(eAddr).isOkOr:
     raiseAssert info & $$error
 
 proc delete*(al: AccountLedger, eAddr: EthAddress) =
   const info = "AccountLedger/delete()"
   # Flush associated storage trie
-  al.distinctBase.stoFlush(eAddr).isOkOr:
+  al.distinctBase.stoDelete(eAddr).isOkOr:
     raiseAssert info & $$error
   # Clear account
   al.distinctBase.delete(eAddr).isOkOr:
diff --git a/nimbus/db/state_db/base.nim b/nimbus/db/state_db/base.nim
index c9912a973..f9b4bf95f 100644
--- a/nimbus/db/state_db/base.nim
+++ b/nimbus/db/state_db/base.nim
@@ -144,8 +144,8 @@ proc subBalance*(db: AccountStateDB, eAddr: EthAddress, delta: UInt256) =
 
 proc clearStorage*(db: AccountStateDB, eAddr: EthAddress) =
   # Flush associated storage trie (will update account record on disk)
-  db.trie.distinctBase.stoFlush(eAddr).isOkOr:
-    raiseAssert "clearStorage():  stoFlush() failed, " & $$error
+  db.trie.distinctBase.stoDelete(eAddr).isOkOr:
+    raiseAssert "clearStorage():  stoDelete() failed, " & $$error
   # Reset storage info locally so that `Aristo` would not complain when
   # updating the account record on disk
   var account = db.getAccount(eAddr)
diff --git a/tests/test_aristo/test_filter.nim b/tests/test_aristo/test_filter.nim
index 20b0aa6de..659ae072e 100644
--- a/tests/test_aristo/test_filter.nim
+++ b/tests/test_aristo/test_filter.nim
@@ -110,7 +110,7 @@ proc dbTriplet(w: LeafQuartet; rdbPath: string): Result[DbTriplet,AristoError] =
   block:
     let report = db.mergeList w[0]
     if report.error != 0:
-      db.finish(flush=true)
+      db.finish(eradicate=true)
       check report.error == 0
       return err(report.error)
     let rc = db.persist()
@@ -130,7 +130,7 @@ proc dbTriplet(w: LeafQuartet; rdbPath: string): Result[DbTriplet,AristoError] =
   for n in 0 ..< dx.len:
     let report = dx[n].mergeList w[n+1]
     if report.error != 0:
-      db.finish(flush=true)
+      db.finish(eradicate=true)
       check (n, report.error) == (n,0)
       return err(report.error)
 
@@ -140,7 +140,7 @@ proc dbTriplet(w: LeafQuartet; rdbPath: string): Result[DbTriplet,AristoError] =
 
 proc cleanUp(dx: var DbTriplet) =
   if not dx[0].isNil:
-    dx[0].finish(flush=true)
+    dx[0].finish(eradicate=true)
     dx.reset
 
 proc isDbEq(a, b: LayerDeltaRef; db: AristoDbRef; noisy = true): bool =
diff --git a/tests/test_aristo/test_tx.nim b/tests/test_aristo/test_tx.nim
index 3d495b7ec..d9f530190 100644
--- a/tests/test_aristo/test_tx.nim
+++ b/tests/test_aristo/test_tx.nim
@@ -112,7 +112,7 @@ proc innerCleanUp(db: var AristoDbRef): bool {.discardable.}  =
     if rx.isOk:
       let rc = rx.value.collapse(commit=false)
       xCheckRc rc.error == 0
-    db.finish(flush=true)
+    db.finish(eradicate=true)
     db = AristoDbRef(nil)
 
 proc schedStow(
@@ -340,7 +340,7 @@ proc testTxMergeAndDeleteOneByOne*(
     fwdRevVfyToggle = true
   defer:
     if not db.isNil:
-      db.finish(flush=true)
+      db.finish(eradicate=true)
 
   for n,w in list:
     # Start with brand new persistent database.
@@ -448,7 +448,7 @@ proc testTxMergeAndDeleteSubTree*(
     db = AristoDbRef(nil)
   defer:
     if not db.isNil:
-      db.finish(flush=true)
+      db.finish(eradicate=true)
 
   for n,w in list:
     # Start with brand new persistent database.
@@ -546,7 +546,7 @@ proc testTxMergeProofAndKvpList*(
     count = 0
   defer:
     if not db.isNil:
-      db.finish(flush=true)
+      db.finish(eradicate=true)
 
   for n,w in list:
 
diff --git a/tests/test_coredb.nim b/tests/test_coredb.nim
index 32cffd581..5dfaa156d 100644
--- a/tests/test_coredb.nim
+++ b/tests/test_coredb.nim
@@ -20,7 +20,8 @@ import
   ../nimbus/db/core_db/persistent,
   ../nimbus/core/chain,
   ./replay/pp,
-  ./test_coredb/[coredb_test_xx, test_chainsync, test_helpers]
+  ./test_coredb/[
+    coredb_test_xx, test_chainsync, test_coredb_helpers, test_helpers]
 
 const
   # If `true`, this compile time option set up `unittest2` for manual parsing
@@ -151,17 +152,17 @@ proc setErrorLevel {.used.} =
 proc initRunnerDB(
     path: string;
     specs: CaptureSpecs;
-    dbType: CoreDbType;
+    dbType: CdbTypeEx;
     pruneHistory: bool;
      ): CommonRef =
   let coreDB =
     # Resolve for static `dbType`
     case dbType:
-    of AristoDbMemory: AristoDbMemory.newCoreDbRef()
-    of AristoDbRocks: AristoDbRocks.newCoreDbRef(path, DbOptions.init())
-    of AristoDbDualRocks: AristoDbDualRocks.newCoreDbRef(path, DbOptions.init())
-    of AristoDbVoid: AristoDbVoid.newCoreDbRef()
-    of Ooops: raiseAssert "Ooops"
+    of CdbAristoMemory: AristoDbMemory.newCoreDbRef()
+    of CdbAristoRocks: AristoDbRocks.newCoreDbRef(path, DbOptions.init())
+    of CdbAristoDualRocks: newCdbAriAristoDualRocks(path, DbOptions.init())
+    of CdbAristoVoid: AristoDbVoid.newCoreDbRef()
+    of CdbOoops: raiseAssert "Ooops"
 
   when false: # or true:
     setDebugLevel()
@@ -198,7 +199,7 @@ proc initRunnerDB(
 proc chainSyncRunner(
     noisy = true;
     capture = memorySampleDefault;
-    dbType = CoreDbType(0);
+    dbType =  CdbTypeEx(0);
     pruneHistory = false;
     profilingOk = false;
     finalDiskCleanUpOk = true;
@@ -220,14 +221,14 @@ proc chainSyncRunner(
 
     dbType = block:
       # Decreasing priority: dbType, capture.dbType, dbTypeDefault
-      var effDbType = dbTypeDefault
-      if dbType != CoreDbType(0):
+      var effDbType = dbTypeDefault.to(CdbTypeEx)
+      if dbType != CdbTypeEx(0):
         effDbType = dbType
       elif capture.dbType != CoreDbType(0):
-        effDbType = capture.dbType
+        effDbType = capture.dbType.to(CdbTypeEx)
       effDbType
 
-    persistent = dbType in CoreDbPersistentTypes
+    persistent = dbType in CdbTypeExPersistent
 
   defer:
     if persistent: baseDir.flushDbDir
@@ -238,7 +239,7 @@ proc chainSyncRunner(
       let
         com = initRunnerDB(dbDir, capture, dbType, pruneHistory)
       defer:
-        com.db.finish(flush = finalDiskCleanUpOk)
+        com.db.finish(eradicate = finalDiskCleanUpOk)
         if profilingOk: noisy.test_chainSyncProfilingPrint numBlocks
         if persistent and finalDiskCleanUpOk: dbDir.flushDbDir
 
@@ -255,7 +256,7 @@ proc chainSyncRunner(
 proc persistentSyncPreLoadAndResumeRunner(
     noisy = true;
     capture = persistentSampleDefault;
-    dbType = CoreDbType(0);
+    dbType = CdbTypeEx(0);
     profilingOk = false;
     pruneHistory = false;
     finalDiskCleanUpOk = true;
@@ -271,14 +272,14 @@ proc persistentSyncPreLoadAndResumeRunner(
 
     dbType = block:
       # Decreasing priority: dbType, capture.dbType, dbTypeDefault
-      var effDbType = dbTypeDefault
-      if dbType != CoreDbType(0):
+      var effDbType = dbTypeDefault.to(CdbTypeEx)
+      if dbType != CdbTypeEx(0):
         effDbType = dbType
       elif capture.dbType != CoreDbType(0):
-        effDbType = capture.dbType
+        effDbType = capture.dbType.to(CdbTypeEx)
       effDbType
 
-  doAssert dbType in CoreDbPersistentTypes
+  doAssert dbType in CdbTypeExPersistent
   defer: baseDir.flushDbDir
 
   let
@@ -292,7 +293,7 @@ proc persistentSyncPreLoadAndResumeRunner(
       let
         com = initRunnerDB(dbDir, capture, dbType, pruneHistory)
       defer:
-        com.db.finish(flush = finalDiskCleanUpOk)
+        com.db.finish(eradicate = finalDiskCleanUpOk)
         if profilingOk: noisy.test_chainSyncProfilingPrint firstPart
 
       if noisy:
@@ -308,7 +309,7 @@ proc persistentSyncPreLoadAndResumeRunner(
       let
         com = initRunnerDB(dbDir, capture, dbType, pruneHistory)
       defer:
-        com.db.finish(flush = finalDiskCleanUpOk)
+        com.db.finish(eradicate = finalDiskCleanUpOk)
         if profilingOk: noisy.test_chainSyncProfilingPrint secndPart
         if finalDiskCleanUpOk: dbDir.flushDbDir
 
@@ -354,7 +355,7 @@ when isMainModule:
     for n,capture in sampleList:
       noisy.profileSection("@sample #" & $n, state):
         noisy.chainSyncRunner(
-          #dbType = AristoDbDualRocks,
+          #dbType = CdbAristoDualRocks,
           capture = capture,
           pruneHistory = true,
           #profilingOk = true,
diff --git a/tests/test_coredb/test_coredb_helpers.nim b/tests/test_coredb/test_coredb_helpers.nim
new file mode 100644
index 000000000..e26e1f5d3
--- /dev/null
+++ b/tests/test_coredb/test_coredb_helpers.nim
@@ -0,0 +1,50 @@
+# Nimbus
+# Copyright (c) 2023-2024 Status Research & Development GmbH
+# Licensed under either of
+#  * Apache License, version 2.0, ([LICENSE-APACHE](LICENSE-APACHE) or
+#    http://www.apache.org/licenses/LICENSE-2.0)
+#  * MIT license ([LICENSE-MIT](LICENSE-MIT) or
+#    http://opensource.org/licenses/MIT)
+# at your option. This file may not be copied, modified, or
+# distributed except according to those terms.
+
+## Some extended rocksdb backend modes for testing
+
+import
+  std/sequtils,
+  ../../nimbus/db/core_db/backend/aristo_rocksdb,
+  ../../nimbus/db/[core_db, opts]
+
+type
+  CdbTypeEx* = enum
+    CdbOoops
+    CdbAristoMemory = AristoDbMemory ## Memory backend emulator
+    CdbAristoRocks  = AristoDbRocks  ## RocksDB backend
+    CdbAristoVoid   = AristoDbVoid   ## No backend
+    CdbAristoDualRocks               ## Dual RocksDB backends for Kvt & Aristo
+
+func to*(cdb: CoreDbType; T: type CdbTypeEx): T =
+  case cdb:
+  # Let the compiler find out whether the enum is complete
+  of Ooops, AristoDbMemory, AristoDbRocks, AristoDbVoid:
+    return CdbTypeEx(cdb.ord)
+
+const
+  CdbTypeExPersistent* =
+    CoreDbPersistentTypes.mapIt(it.to(CdbTypeEx)) & @[CdbAristoDualRocks]
+
+func `$`*(w: CdbTypeEx): string =
+  case w:
+  of CdbOoops, CdbAristoMemory, CdbAristoRocks, CdbAristoVoid:
+    $CoreDbType(w.ord)
+  of CdbAristoDualRocks:
+    "CdbAristoDualRocks"
+
+proc newCdbAriAristoDualRocks*(path: string, opts: DbOptions): CoreDbRef =
+  ## For debugging, there is the `AristoDbDualRocks` database with split
+  ## backends for `Aristo` and `KVT`. This database is not compatible with
+  ## `AristoDbRocks` so it cannot be reliably switched between both versions
+  ## with consecutive sessions.
+  newAristoDualRocksDbCoreDbRef path, opts
+
+# End