From 4346d2fc765f40a9388108c06cf1ee132d663923 Mon Sep 17 00:00:00 2001 From: SomberNight Date: Fri, 12 Feb 2021 21:31:18 +0100 Subject: [PATCH] synchronizer: ensure fairness between wallets Scenario (prior to change): User opens wallet1 with 10k addresses, and then immediately opens wallet2 with 100 addresses. wallet1 will synchronise first, fully, and only then will wallet2 start syncing. Now, wallet1 and wallet2 will sync concurrently (and wallet2 will finish much sooner as expected). --- electrum/synchronizer.py | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-) diff --git a/electrum/synchronizer.py b/electrum/synchronizer.py index 9d619b47e..7f31de859 100644 --- a/electrum/synchronizer.py +++ b/electrum/synchronizer.py @@ -61,6 +61,10 @@ class SynchronizerBase(NetworkJobOnDefaultServer): def __init__(self, network: 'Network'): self.asyncio_loop = network.asyncio_loop self._reset_request_counters() + # Ensure fairness between Synchronizers. e.g. if multiple wallets + # are open, a large wallet should not starve the small wallets: + self._network_request_semaphore = asyncio.Semaphore(100) + NetworkJobOnDefaultServer.__init__(self, network) def _reset(self): @@ -106,7 +110,8 @@ class SynchronizerBase(NetworkJobOnDefaultServer): self.scripthash_to_address[h] = addr self._requests_sent += 1 try: - await self.session.subscribe('blockchain.scripthash.subscribe', [h], self.status_queue) + async with self._network_request_semaphore: + await self.session.subscribe('blockchain.scripthash.subscribe', [h], self.status_queue) except RPCError as e: if e.message == 'history too large': # no unique error code raise GracefulDisconnect(e, log_level=logging.ERROR) from e @@ -167,7 +172,8 @@ class Synchronizer(SynchronizerBase): self.requested_histories.add((addr, status)) h = address_to_scripthash(addr) self._requests_sent += 1 - result = await self.interface.get_history_for_scripthash(h) + async with self._network_request_semaphore: + result = await self.interface.get_history_for_scripthash(h) self._requests_answered += 1 self.logger.info(f"receiving history {addr} {len(result)}") hashes = set(map(lambda item: item['tx_hash'], result)) @@ -210,7 +216,8 @@ class Synchronizer(SynchronizerBase): async def _get_transaction(self, tx_hash, *, allow_server_not_finding_tx=False): self._requests_sent += 1 try: - raw_tx = await self.interface.get_transaction(tx_hash) + async with self._network_request_semaphore: + raw_tx = await self.interface.get_transaction(tx_hash) except RPCError as e: # most likely, "No such mempool or blockchain transaction" if allow_server_not_finding_tx: