Improve flow for opening DBs

compact_history.py

@@ -48,7 +48,7 @@ async def compact_history():
     environ['DAEMON_URL'] = ''   # Avoid Env erroring out
     env = Env()
     db = DB(env)
-    await db.open_for_sync()
+    await db.open_for_compacting()
 
     assert not db.first_sync
     history = db.history

contrib/query.py

@@ -62,7 +62,7 @@ async def query(args):
     db = DB(env)
     coin = env.coin
 
-    await db._open_dbs(False)
+    await db.open_for_serving()
 
     if not args.scripts:
         await print_stats(db.hist_db, db.utxo_db)

electrumx/server/block_processor.py

@@ -159,7 +159,6 @@ class BlockProcessor(electrumx.server.db.DB):
         self.prefetcher = Prefetcher(daemon, env.coin, self.blocks_event)
 
         # Meta
-        self.cache_MB = env.cache_MB
         self.next_cache_check = 0
         self.last_flush = time.time()
         self.touched = set()
@@ -448,8 +447,9 @@ class BlockProcessor(electrumx.server.db.DB):
 
         # Flush history if it takes up over 20% of cache memory.
         # Flush UTXOs once they take up 80% of cache memory.
-        if utxo_MB + hist_MB >= self.cache_MB or hist_MB >= self.cache_MB // 5:
-            return utxo_MB >= self.cache_MB * 4 // 5
+        cache_MB = self.env.cache_MB
+        if utxo_MB + hist_MB >= cache_MB or hist_MB >= cache_MB // 5:
+            return utxo_MB >= cache_MB * 4 // 5
         return None
 
     def advance_blocks(self, blocks):
@@ -755,18 +755,10 @@ class BlockProcessor(electrumx.server.db.DB):
 
     async def _first_open_dbs(self):
         await self.open_for_sync()
-        # An incomplete compaction needs to be cancelled otherwise
-        # restarting it will corrupt the history
-        self.history.cancel_compaction()
-        # These are our state as we move ahead of DB state
-        self.fs_height = self.db_height
-        self.fs_tx_count = self.db_tx_count
         self.height = self.db_height
         self.tip = self.db_tip
         self.tx_count = self.db_tx_count
         self.last_flush_tx_count = self.tx_count
-        if self.utxo_db.for_sync:
-            self.logger.info(f'flushing DB cache at {self.cache_MB:,d} MB')
 
     # --- External API
 

electrumx/server/db.py

@@ -90,7 +90,7 @@ class DB(object):
         else:
             assert self.db_tx_count == 0
 
-    async def _open_dbs(self, for_sync):
+    async def _open_dbs(self, for_sync, compacting):
         assert self.utxo_db is None
 
         # First UTXO DB
@@ -110,12 +110,16 @@ class DB(object):
 
         # Then history DB
         self.utxo_flush_count = self.history.open_db(self.db_class, for_sync,
-                                                     self.utxo_flush_count)
+                                                     self.utxo_flush_count,
+                                                     compacting)
         self.clear_excess_undo_info()
 
         # Read TX counts (requires meta directory)
         await self._read_tx_counts()
 
+    async def open_for_compacting(self):
+        await self._open_dbs(True, True)
+
     async def open_for_sync(self):
         '''Open the databases to sync to the daemon.
 
@@ -123,7 +127,7 @@ class DB(object):
         synchronization.  When serving clients we want the open files for
         serving network connections.
         '''
-        await self._open_dbs(True)
+        await self._open_dbs(True, False)
 
     async def open_for_serving(self):
         '''Open the databases for serving.  If they are already open they are
@@ -134,7 +138,7 @@ class DB(object):
             self.utxo_db.close()
             self.history.close_db()
             self.utxo_db = None
-        await self._open_dbs(False)
+        await self._open_dbs(False, False)
 
     # Header merkle cache
 
@@ -395,6 +399,10 @@ class DB(object):
             self.wall_time = state['wall_time']
             self.first_sync = state['first_sync']
 
+        # These are our state as we move ahead of DB state
+        self.fs_height = self.db_height
+        self.fs_tx_count = self.db_tx_count
+
         # Log some stats
         self.logger.info('DB version: {:d}'.format(self.db_version))
         self.logger.info('coin: {}'.format(self.coin.NAME))
@@ -402,6 +410,8 @@ class DB(object):
         self.logger.info('height: {:,d}'.format(self.db_height))
         self.logger.info('tip: {}'.format(hash_to_hex_str(self.db_tip)))
         self.logger.info('tx count: {:,d}'.format(self.db_tx_count))
+        if self.utxo_db.for_sync:
+            self.logger.info(f'flushing DB cache at {self.env.cache_MB:,d} MB')
         if self.first_sync:
             self.logger.info('sync time so far: {}'
                              .format(util.formatted_time(self.wall_time)))

electrumx/server/history.py

@@ -32,10 +32,14 @@ class History(object):
         self.unflushed_count = 0
         self.db = None
 
-    def open_db(self, db_class, for_sync, utxo_flush_count):
+    def open_db(self, db_class, for_sync, utxo_flush_count, compacting):
         self.db = db_class('hist', for_sync)
         self.read_state()
         self.clear_excess(utxo_flush_count)
+        # An incomplete compaction needs to be cancelled otherwise
+        # restarting it will corrupt the history
+        if not compacting:
+            self._cancel_compaction()
         return self.flush_count
 
     def close_db(self):
@@ -314,7 +318,7 @@ class History(object):
                                  100 * cursor / 65536))
         return write_size
 
-    def cancel_compaction(self):
+    def _cancel_compaction(self):
         if self.comp_cursor != -1:
             self.logger.warning('cancelling in-progress history compaction')
             self.comp_flush_count = -1