add dropChannel to persistence, replace the loop in dropChannelFromPersistence with a single call

sds.nim

@@ -471,7 +471,7 @@ proc resetReliabilityManager*(rm: ReliabilityManager): Result[void, ReliabilityE
   withLock rm.lock:
     try:
       for channelId, channel in rm.channels:
-        rm.dropChannelFromPersistence(channelId, channel)
+        rm.dropChannelFromPersistence(channelId)
         channel.lamportTimestamp = 0
         channel.messageHistory.clear()
         channel.outgoingBuffer.setLen(0)

sds/sds_utils.nim

@@ -15,22 +15,12 @@ proc defaultConfig*(): ReliabilityConfig =
   return ReliabilityConfig.init()
 
 proc dropChannelFromPersistence*(
-    rm: ReliabilityManager, channelId: SdsChannelID, channel: ChannelContext
+    rm: ReliabilityManager, channelId: SdsChannelID
 ) {.gcsafe, raises: [].} =
-  ## Fires per-entry remove calls for every buffered entry in the channel.
+  ## Wipes all persisted state for a channel via a single backend call.
-  ## Called by cleanup / removeChannel / resetReliabilityManager before they
+  ## Called by removeChannel / resetReliabilityManager before they clear
-  ## wipe in-memory state, so on-disk state stays consistent.
+  ## in-memory state. Backend executes the wipe in one transaction.
-  for unack in channel.outgoingBuffer:
+  rm.persistence.dropChannel(channelId)
-    rm.persistence.removeOutgoing(channelId, unack.message.messageId)
-  for msgId in channel.incomingBuffer.keys:
-    rm.persistence.removeIncoming(channelId, msgId)
-  for msgId in channel.messageHistory.keys:
-    rm.persistence.removeLogEntry(channelId, msgId)
-  for msgId in channel.outgoingRepairBuffer.keys:
-    rm.persistence.removeOutgoingRepair(channelId, msgId)
-  for msgId in channel.incomingRepairBuffer.keys:
-    rm.persistence.removeIncomingRepair(channelId, msgId)
-  rm.persistence.saveLamport(channelId, 0)
 
 proc cleanup*(rm: ReliabilityManager) {.raises: [].} =
   ## Releases in-memory state. Does NOT wipe persistence — the manager may be
@@ -301,7 +291,7 @@ proc removeChannel*(
     try:
       if channelId in rm.channels:
         let channel = rm.channels[channelId]
-        rm.dropChannelFromPersistence(channelId, channel)
+        rm.dropChannelFromPersistence(channelId)
         channel.outgoingBuffer.setLen(0)
         channel.incomingBuffer.clear()
         channel.messageHistory.clear()

sds/types/persistence.nim

@@ -75,6 +75,13 @@ type
     removeIncomingRepair*:
       proc(channelId: SdsChannelID, msgId: SdsMessageID) {.gcsafe, raises: [].}
 
+    # Wipe all persisted state for a channel in one transactional call.
+    # Called by removeChannel / resetReliabilityManager. Backends should
+    # implement this atomically (e.g. one BEGIN/COMMIT) — a per-row loop on
+    # the nim-sds side would mean N fsyncs per drop.
+    dropChannel*:
+      proc(channelId: SdsChannelID) {.gcsafe, raises: [].}
+
     # Bootstrap on `addChannel` / `getOrCreateChannel`.
     loadAllForChannel*:
       proc(channelId: SdsChannelID): ChannelSnapshot {.gcsafe, raises: [].}
@@ -112,6 +119,8 @@ proc noOpPersistence*(): Persistence =
       discard,
     removeIncomingRepair: proc(channelId: SdsChannelID, msgId: SdsMessageID) =
       discard,
+    dropChannel: proc(channelId: SdsChannelID) =
+      discard,
     loadAllForChannel: proc(channelId: SdsChannelID): ChannelSnapshot =
       ChannelSnapshot(),
   )

tests/in_memory_persistence.nim

@@ -14,6 +14,9 @@ type InMemoryStore* = ref object
   incoming*: Table[SdsChannelID, OrderedTable[SdsMessageID, IncomingMessage]]
   outgoingRepair*: Table[SdsChannelID, OrderedTable[SdsMessageID, OutgoingRepairEntry]]
   incomingRepair*: Table[SdsChannelID, OrderedTable[SdsMessageID, IncomingRepairEntry]]
+  dropChannelCalls*: Table[SdsChannelID, int]
+    ## Per-channel counter; lets tests assert dropChannel is invoked exactly
+    ## once per logical drop (not N times — see PR #66 review).
 
 proc newInMemoryStore*(): InMemoryStore =
   InMemoryStore()
@@ -89,6 +92,17 @@ proc newInMemoryPersistence*(store: InMemoryStore): Persistence =
         if channelId in store.incomingRepair:
           store.incomingRepair[channelId].del(msgId),
 
+    dropChannel: proc(channelId: SdsChannelID) {.gcsafe, raises: [].} =
+      {.cast(raises: []).}:
+        store.lamports.del(channelId)
+        store.log.del(channelId)
+        store.outgoing.del(channelId)
+        store.incoming.del(channelId)
+        store.outgoingRepair.del(channelId)
+        store.incomingRepair.del(channelId)
+        store.dropChannelCalls[channelId] =
+          store.dropChannelCalls.getOrDefault(channelId) + 1,
+
     loadAllForChannel: proc(channelId: SdsChannelID): ChannelSnapshot {.gcsafe, raises: [].} =
       {.cast(raises: []).}:
         var snap = ChannelSnapshot()

tests/test_persistence.nim

@@ -91,7 +91,9 @@ suite "Persistence: write → restart → read-back":
     check "msg-x" notin store.outgoing[testChannel]
     rm.cleanup()
 
-  test "removeChannel fires per-entry removes":
+  test "removeChannel issues exactly one dropChannel call and wipes all state":
+    # Regression for PR #66 review: removal must be a single transactional
+    # drop, not N per-row removes — otherwise SQLite eats N fsyncs per drop.
     let store = newInMemoryStore()
     let p = newInMemoryPersistence(store)
     let rm = newReliabilityManager(persistence = p).get()
@@ -99,9 +101,15 @@ suite "Persistence: write → restart → read-back":
     discard rm.wrapOutgoingMessage(@[1.byte], "msg-r", testChannel)
     check store.outgoing[testChannel].len == 1
     check store.lamports[testChannel] > 0
+
     check rm.removeChannel(testChannel).isOk()
-    check store.outgoing[testChannel].len == 0
+    check store.dropChannelCalls.getOrDefault(testChannel) == 1
-    check store.lamports[testChannel] == 0
+    check testChannel notin store.outgoing
+    check testChannel notin store.lamports
+    check testChannel notin store.log
+    check testChannel notin store.incoming
+    check testChannel notin store.outgoingRepair
+    check testChannel notin store.incomingRepair
     rm.cleanup()
 
   test "noOpPersistence keeps existing manager working":
@@ -186,8 +194,8 @@ suite "Persistence: write → restart → read-back":
     rm2.cleanup()
 
   test "removeChannel + recreate does not inherit stale lamport":
-    # Regression: dropChannelFromPersistence used to skip saveLamport(0),
+    # Regression: dropChannel must wipe the lamport row; otherwise a recreate
-    # so the channels row survived removeChannel and a recreate inherited it.
+    # of the same channelId after restart picks up the old timestamp.
     let store = newInMemoryStore()
     let p1 = newInMemoryPersistence(store)
     let rm1 = newReliabilityManager(persistence = p1).get()
@@ -195,7 +203,7 @@ suite "Persistence: write → restart → read-back":
     discard rm1.wrapOutgoingMessage(@[1.byte], "m-old", testChannel)
     check store.lamports[testChannel] > 0
     check rm1.removeChannel(testChannel).isOk()
-    check store.lamports[testChannel] == 0
+    check testChannel notin store.lamports
     rm1.cleanup()
 
     # Recreate the same channelId after a restart — must start fresh.