More logical mempool hash handling

Fixes the issue whereby notifications weren't sent as long as new blocks
kept coming in.  Now a new height notification, with an appropriate mempool
update, is sent after each batch of blocks is processed.

server/block_processor.py

@@ -29,7 +29,6 @@ class Prefetcher(LoggedClass):
     def __init__(self, bp):
         super().__init__()
         self.bp = bp
-        self.caught_up = False
         # Access to fetched_height should be protected by the semaphore
         self.fetched_height = None
         self.semaphore = asyncio.Semaphore()
@@ -84,7 +83,14 @@ class Prefetcher(LoggedClass):
         Repeats until the queue is full or caught up.
         '''
         daemon = self.bp.daemon
-        daemon_height = await daemon.height(self.bp.caught_up_event.is_set())
+        # If caught up, refresh the mempool before the current height
+        caught_up = self.bp.caught_up_event.is_set()
+        if caught_up:
+            mempool = await daemon.mempool_hashes()
+        else:
+            mempool = []
+
+        daemon_height = await daemon.height()
         with await self.semaphore:
             while self.cache_size < self.min_cache_size:
                 # Try and catch up all blocks but limit to room in cache.
@@ -94,14 +100,15 @@ class Prefetcher(LoggedClass):
                 count = min(daemon_height - self.fetched_height, cache_room)
                 count = min(500, max(count, 0))
                 if not count:
-                    if not self.caught_up:
-                        self.caught_up = True
+                    if caught_up:
+                        self.bp.set_mempool_hashes(mempool)
+                    else:
                         self.bp.on_prefetcher_first_caught_up()
                     return False
 
                 first = self.fetched_height + 1
                 hex_hashes = await daemon.block_hex_hashes(first, count)
-                if self.caught_up:
+                if caught_up:
                     self.logger.info('new block height {:,d} hash {}'
                                      .format(first + count-1, hex_hashes[-1]))
                 blocks = await daemon.raw_blocks(hex_hashes)
@@ -121,7 +128,7 @@ class Prefetcher(LoggedClass):
                 else:
                     self.ave_size = (size + (10 - count) * self.ave_size) // 10
 
-                self.bp.on_prefetched_blocks(blocks, first)
+                self.bp.on_prefetched_blocks(blocks, first, mempool)
                 self.cache_size += size
                 self.fetched_height += count
 
@@ -188,9 +195,10 @@ class BlockProcessor(server.db.DB):
         '''Add the task to our task queue.'''
         self.task_queue.put_nowait(task)
 
-    def on_prefetched_blocks(self, blocks, first):
+    def on_prefetched_blocks(self, blocks, first, mempool):
         '''Called by the prefetcher when it has prefetched some blocks.'''
-        self.add_task(partial(self.check_and_advance_blocks, blocks, first))
+        self.add_task(partial(self.check_and_advance_blocks, blocks, first,
+                              mempool))
 
     def on_prefetcher_first_caught_up(self):
         '''Called by the prefetcher when it first catches up.'''
@@ -225,7 +233,10 @@ class BlockProcessor(server.db.DB):
         self.open_dbs()
         self.caught_up_event.set()
 
-    async def check_and_advance_blocks(self, blocks, first):
+    def set_mempool_hashes(self, mempool):
+        self.controller.mempool.set_hashes(mempool)
+
+    async def check_and_advance_blocks(self, blocks, first, mempool):
         '''Process the list of blocks passed.  Detects and handles reorgs.'''
         self.prefetcher.processing_blocks(blocks)
         if first != self.height + 1:
@@ -251,6 +262,7 @@ class BlockProcessor(server.db.DB):
                 self.logger.info('processed {:,d} block{} in {:.1f}s'
                                  .format(len(blocks), s,
                                          time.time() - start))
+            self.set_mempool_hashes(mempool)
         elif hprevs[0] != chain[0]:
             await self.reorg_chain()
         else:

server/daemon.py

@@ -38,8 +38,6 @@ class Daemon(util.LoggedClass):
         super().__init__()
         self.set_urls(urls)
         self._height = None
-        self._mempool_hashes = set()
-        self.mempool_refresh_event = asyncio.Event()
         # Limit concurrent RPC calls to this number.
         # See DEFAULT_HTTP_WORKQUEUE in bitcoind, which is typically 16
         self.workqueue_semaphore = asyncio.Semaphore(value=10)
@@ -210,7 +208,7 @@ class Daemon(util.LoggedClass):
         return [bytes.fromhex(block) for block in blocks]
 
     async def mempool_hashes(self):
-        '''Update our record of the daemon's mempool hashes.'''
+        '''Return a list of the daemon's mempool hashes.'''
         return await self._send_single('getrawmempool')
 
     async def estimatefee(self, params):
@@ -245,18 +243,11 @@ class Daemon(util.LoggedClass):
         '''Broadcast a transaction to the network.'''
         return await self._send_single('sendrawtransaction', params)
 
-    async def height(self, mempool=False):
+    async def height(self):
         '''Query the daemon for its current height.'''
         self._height = await self._send_single('getblockcount')
-        if mempool:
-            self._mempool_hashes = set(await self.mempool_hashes())
-            self.mempool_refresh_event.set()
         return self._height
 
-    def cached_mempool_hashes(self):
-        '''Return the cached mempool hashes.'''
-        return self._mempool_hashes
-
     def cached_height(self):
         '''Return the cached daemon height.
 

server/mempool.py

@@ -37,6 +37,8 @@ class MemPool(util.LoggedClass):
         self.controller = controller
         self.coin = bp.coin
         self.db = bp
+        self.hashes = set()
+        self.mempool_refresh_event = asyncio.Event()
         self.touched = bp.touched
         self.touched_event = asyncio.Event()
         self.prioritized = set()
@@ -49,6 +51,11 @@ class MemPool(util.LoggedClass):
         initial mempool sync.'''
         self.prioritized.add(tx_hash)
 
+    def set_hashes(self, hashes):
+        '''Save the list of mempool hashes.'''
+        self.hashes = set(hashes)
+        self.mempool_refresh_event.set()
+
     def resync_daemon_hashes(self, unprocessed, unfetched):
         '''Re-sync self.txs with the list of hashes in the daemon's mempool.
 
@@ -59,8 +66,7 @@ class MemPool(util.LoggedClass):
         hashXs = self.hashXs
         touched = self.touched
 
-        hashes = self.daemon.cached_mempool_hashes()
-        gone = set(txs).difference(hashes)
+        gone = set(txs).difference(self.hashes)
         for hex_hash in gone:
             unfetched.discard(hex_hash)
             unprocessed.pop(hex_hash, None)
@@ -75,7 +81,7 @@ class MemPool(util.LoggedClass):
                         del hashXs[hashX]
                 touched.update(tx_hashXs)
 
-        new = hashes.difference(txs)
+        new = self.hashes.difference(txs)
         unfetched.update(new)
         for hex_hash in new:
             txs[hex_hash] = None
@@ -92,15 +98,14 @@ class MemPool(util.LoggedClass):
         fetch_size = 800
         process_some = self.async_process_some(unfetched, fetch_size // 2)
 
-        await self.daemon.mempool_refresh_event.wait()
+        await self.mempool_refresh_event.wait()
         self.logger.info('beginning processing of daemon mempool.  '
                          'This can take some time...')
         next_log = 0
         loops = -1  # Zero during initial catchup
 
         while True:
-            # Avoid double notifications if processing a block
-            if self.touched and not self.processing_new_block():
+            if self.touched:
                 self.touched_event.set()
 
             # Log progress / state
@@ -120,10 +125,10 @@ class MemPool(util.LoggedClass):
             try:
                 if not todo:
                     self.prioritized.clear()
-                    await self.daemon.mempool_refresh_event.wait()
+                    await self.mempool_refresh_event.wait()
 
                 self.resync_daemon_hashes(unprocessed, unfetched)
-                self.daemon.mempool_refresh_event.clear()
+                self.mempool_refresh_event.clear()
 
                 if unfetched:
                     count = min(len(unfetched), fetch_size)
@@ -177,10 +182,6 @@ class MemPool(util.LoggedClass):
 
         return process
 
-    def processing_new_block(self):
-        '''Return True if we're processing a new block.'''
-        return self.daemon.cached_height() > self.db.db_height
-
     async def fetch_raw_txs(self, hex_hashes):
         '''Fetch a list of mempool transactions.'''
         raw_txs = await self.daemon.getrawtransactions(hex_hashes)