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This commit is contained in:
Jack Robison 2020-05-04 13:47:37 -04:00
parent e3abab6d4d
commit 750ff448ad
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7
lbry/wallet/database.py
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@ -181,12 +181,18 @@ class AIOSQLite:
async def run(self, fun, *args, **kwargs): async def run(self, fun, *args, **kwargs):
self.write_count_metric.inc() self.write_count_metric.inc()
self.waiting_writes_metric.inc() self.waiting_writes_metric.inc()
# it's possible many writes are coming in one after the other, these can
# block reader calls for a long time
# if the reader waits for the writers to finish and then has to wait for
# yet more, it will clear the urgent_read_done event to block more writers
# piling on
try: try:
await self.urgent_read_done.wait() await self.urgent_read_done.wait()
except Exception as e: except Exception as e:
self.waiting_writes_metric.dec() self.waiting_writes_metric.dec()
raise e raise e
self.writers += 1 self.writers += 1
# block readers
self.read_ready.clear() self.read_ready.clear()
try: try:
async with self.write_lock: async with self.write_lock:
@ -197,6 +203,7 @@ class AIOSQLite:
self.writers -= 1 self.writers -= 1
self.waiting_writes_metric.dec() self.waiting_writes_metric.dec()
if not self.writers: if not self.writers:
# unblock the readers once the last enqueued writer finishes
self.read_ready.set() self.read_ready.set()
def __run_transaction(self, fun: Callable[[sqlite3.Connection, Any, Any], Any], *args, **kwargs): def __run_transaction(self, fun: Callable[[sqlite3.Connection, Any, Any], Any], *args, **kwargs):