add CACHE_ALL_TX_HASHES setting to optionally use more memory to save i/o

lbry/wallet/server/block_processor.py

@@ -490,9 +490,7 @@ class BlockProcessor:
 
             if signing_channel:
                 raw_channel_tx = self.db.prefix_db.tx.get(
-                    self.db.prefix_db.tx_hash.get(
+                    self.db.get_tx_hash(signing_channel.tx_num), deserialize_value=False
-                        signing_channel.tx_num, deserialize_value=False
-                    ), deserialize_value=False
                 )
             channel_pub_key_bytes = None
             try:
@@ -1501,6 +1499,9 @@ class BlockProcessor:
                 self._abandon_claim(abandoned_claim_hash, tx_num, nout, normalized_name)
             self.pending_transactions[tx_count] = tx_hash
             self.pending_transaction_num_mapping[tx_hash] = tx_count
+            if self.env.cache_all_tx_hashes:
+                self.db.total_transactions.append(tx_hash)
+                self.db.tx_num_mapping[tx_hash] = tx_count
             tx_count += 1
 
         # handle expired claims
@@ -1608,6 +1609,11 @@ class BlockProcessor:
         self.db.headers.pop()
         self.db.tx_counts.pop()
         self.tip = self.coin.header_hash(self.db.headers[-1])
+        if self.env.cache_all_tx_hashes:
+            while len(self.db.total_transactions) > self.db.tx_counts[-1]:
+                self.db.tx_num_mapping.pop(self.db.total_transactions.pop())
+                self.tx_count -= 1
+        else:
             self.tx_count = self.db.tx_counts[-1]
         self.height -= 1
         # self.touched can include other addresses which is
@@ -1659,7 +1665,7 @@ class BlockProcessor:
         if tx_hash in self.pending_transaction_num_mapping:
             return self.pending_transaction_num_mapping[tx_hash]
         else:
-            return self.db.prefix_db.tx_num.get(tx_hash).tx_num
+            return self.db.get_tx_num(tx_hash)
 
     def spend_utxo(self, tx_hash: bytes, nout: int):
         hashX, amount = self.utxo_cache.pop((tx_hash, nout), (None, None))

lbry/wallet/server/env.py

@@ -78,6 +78,7 @@ class Env:
         self.anon_logs = self.boolean('ANON_LOGS', False)
         self.log_sessions = self.integer('LOG_SESSIONS', 3600)
         self.allow_lan_udp = self.boolean('ALLOW_LAN_UDP', False)
+        self.cache_all_tx_hashes = self.boolean('CACHE_ALL_TX_HASHES', False)
         self.country = self.default('COUNTRY', 'US')
         # Peer discovery
         self.peer_discovery = self.peer_discovery_enum()

lbry/wallet/server/leveldb.py

@@ -113,6 +113,8 @@ class LevelDB:
         self.header_mc = MerkleCache(self.merkle, self.fs_block_hashes)
 
         self._tx_and_merkle_cache = LRUCacheWithMetrics(2 ** 16, metric_name='tx_and_merkle', namespace="wallet_server")
+        self.total_transactions: List[bytes] = []
+        self.tx_num_mapping: Dict[bytes, int] = {}
 
         self.claim_to_txo: Dict[bytes, ClaimToTXOValue] = {}
         self.txo_to_claim: DefaultDict[int, Dict[int, bytes]] = defaultdict(dict)
@@ -201,7 +203,7 @@ class LevelDB:
             normalized_name = name
         controlling_claim = self.get_controlling_claim(normalized_name)
 
-        tx_hash = self.prefix_db.tx_hash.get(tx_num, deserialize_value=False)
+        tx_hash = self.get_tx_hash(tx_num)
         height = bisect_right(self.tx_counts, tx_num)
         created_height = bisect_right(self.tx_counts, root_tx_num)
         last_take_over_height = controlling_claim.height
@@ -462,7 +464,7 @@ class LevelDB:
     def get_expired_by_height(self, height: int) -> Dict[bytes, Tuple[int, int, str, TxInput]]:
         expired = {}
         for k, v in self.prefix_db.claim_expiration.iterate(prefix=(height,)):
-            tx_hash = self.prefix_db.tx_hash.get(k.tx_num, deserialize_value=False)
+            tx_hash = self.get_tx_hash(k.tx_num)
             tx = self.coin.transaction(self.prefix_db.tx.get(tx_hash, deserialize_value=False))
             # treat it like a claim spend so it will delete/abandon properly
             # the _spend_claim function this result is fed to expects a txi, so make a mock one
@@ -527,7 +529,7 @@ class LevelDB:
             if not reposted_claim:
                 return
             reposted_metadata = self.get_claim_metadata(
-                self.prefix_db.tx_hash.get(reposted_claim.tx_num, deserialize_value=False), reposted_claim.position
+                self.get_tx_hash(reposted_claim.tx_num), reposted_claim.position
             )
             if not reposted_metadata:
                 return
@@ -541,7 +543,7 @@ class LevelDB:
         reposted_fee_currency = None
         reposted_duration = None
         if reposted_claim:
-            reposted_tx_hash = self.prefix_db.tx_hash.get(reposted_claim.tx_num, deserialize_value=False)
+            reposted_tx_hash = self.get_tx_hash(reposted_claim.tx_num)
             raw_reposted_claim_tx = self.prefix_db.tx.get(reposted_tx_hash, deserialize_value=False)
             try:
                 reposted_claim_txo = self.coin.transaction(
@@ -793,6 +795,21 @@ class LevelDB:
         assert len(headers) - 1 == self.db_height, f"{len(headers)} vs {self.db_height}"
         self.headers = headers
 
+    async def _read_tx_hashes(self):
+        def _read_tx_hashes():
+            return list(self.prefix_db.tx_hash.iterate(include_key=False, fill_cache=False, deserialize_value=False))
+
+        self.logger.info("loading tx hashes")
+        self.total_transactions.clear()
+        self.tx_num_mapping.clear()
+        start = time.perf_counter()
+        self.total_transactions.extend(await asyncio.get_event_loop().run_in_executor(None, _read_tx_hashes))
+        self.tx_num_mapping = {
+            tx_hash: tx_num for tx_num, tx_hash in enumerate(self.total_transactions)
+        }
+        ts = time.perf_counter() - start
+        self.logger.info("loaded %i tx hashes in %ss", len(self.total_transactions), round(ts, 4))
+
     def estimate_timestamp(self, height: int) -> int:
         if height < len(self.headers):
             return struct.unpack('<I', self.headers[height][100:104])[0]
@@ -837,6 +854,8 @@ class LevelDB:
         await self._read_tx_counts()
         await self._read_headers()
         await self._read_claim_txos()
+        if self.env.cache_all_tx_hashes:
+            await self._read_tx_hashes()
 
         # start search index
         await self.search_index.start()
@@ -844,6 +863,16 @@ class LevelDB:
     def close(self):
         self.prefix_db.close()
 
+    def get_tx_hash(self, tx_num: int) -> bytes:
+        if self.env.cache_all_tx_hashes:
+            return self.total_transactions[tx_num]
+        return self.prefix_db.tx_hash.get(tx_num, deserialize_value=False)
+
+    def get_tx_num(self, tx_hash: bytes) -> int:
+        if self.env.cache_all_tx_hashes:
+            return self.tx_num_mapping[tx_hash]
+        return self.prefix_db.tx_num.get(tx_hash).tx_num
+
     # Header merkle cache
 
     async def populate_header_merkle_cache(self):
@@ -900,7 +929,7 @@ class LevelDB:
         if tx_height > self.db_height:
             return None, tx_height
         try:
-            return self.prefix_db.tx_hash.get(tx_num, deserialize_value=False), tx_height
+            return self.get_tx_hash(tx_num), tx_height
         except IndexError:
             self.logger.exception(
                 "Failed to access a cached transaction, known bug #3142 "
@@ -964,13 +993,13 @@ class LevelDB:
         txs = []
         txs_extend = txs.extend
         for hist in self.prefix_db.hashX_history.iterate(prefix=(hashX,), include_key=False):
-            txs_extend([
+            txs_extend(hist)
-                (self.prefix_db.tx_hash.get(tx_num, deserialize_value=False), bisect_right(self.tx_counts, tx_num))
-                for tx_num in hist
-            ])
             if len(txs) >= limit:
                 break
-        return txs
+        return [
+            (self.get_tx_hash(tx_num), bisect_right(self.tx_counts, tx_num))
+            for tx_num in txs
+        ]
 
     async def limited_history(self, hashX, *, limit=1000):
         """Return an unpruned, sorted list of (tx_hash, height) tuples of