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fixed issues with database transaction isolation

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This commit is contained in:
Lex Berezhny 2020-07-14 16:46:24 -04:00
parent 1c29ae7204
commit a4680878c4
5 changed files with 80 additions and 77 deletions
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12
lbry/blockchain/sync/blocks.py
View file

@ -91,9 +91,7 @@ def sync_spends(initial_sync: bool, p: ProgressContext):
# 3. drop old txi and vacuum
p.ctx.execute(text("DROP TABLE old_txi;"))
if p.ctx.is_postgres:
with p.ctx.engine.connect() as c:
c.execute(text("COMMIT;"))
c.execute(text("VACUUM ANALYZE txi;"))
p.ctx.execute_notx(text("VACUUM ANALYZE txi;"))
p.step()
for constraint in pg_add_txi_constraints_and_indexes:
if p.ctx.is_postgres:
@ -119,9 +117,7 @@ def sync_spends(initial_sync: bool, p: ProgressContext):
# 6. drop old txo
p.ctx.execute(text("DROP TABLE old_txo;"))
if p.ctx.is_postgres:
with p.ctx.engine.connect() as c:
c.execute(text("COMMIT;"))
c.execute(text("VACUUM ANALYZE txo;"))
p.ctx.execute_notx(text("VACUUM ANALYZE txo;"))
p.step()
for constraint in pg_add_txo_constraints_and_indexes:
if p.ctx.is_postgres:
@ -137,9 +133,7 @@ def sync_spends(initial_sync: bool, p: ProgressContext):
p.step()
# 3. Update visibility map, which speeds up index-only scans.
if p.ctx.is_postgres:
with p.ctx.engine.connect() as c:
c.execute(text("COMMIT;"))
c.execute(text("VACUUM txo;"))
p.ctx.execute_notx(text("VACUUM txo;"))
p.step()

23
lbry/blockchain/sync/claims.py
View file

@ -116,7 +116,7 @@ def claims_insert(
), progress_id=blocks[0], label=make_label("add claims", blocks)
)
with p.ctx.engine.connect().execution_options(stream_results=True) as c:
with p.ctx.connect_streaming() as c:
loader = p.ctx.get_bulk_loader()
cursor = c.execute(select_claims_for_saving(
blocks, missing_in_claims_table=missing_in_claims_table
@ -146,12 +146,12 @@ def claims_insert(
@event_emitter("blockchain.sync.claims.indexes", "steps")
def claims_constraints_and_indexes(p: ProgressContext):
p.start(1 + len(pg_add_claim_and_tag_constraints_and_indexes))
p.start(2 + len(pg_add_claim_and_tag_constraints_and_indexes))
if p.ctx.is_postgres:
with p.ctx.engine.connect() as c:
c.execute(text("COMMIT;"))
c.execute(text("VACUUM ANALYZE claim;"))
c.execute(text("VACUUM ANALYZE tag;"))
p.ctx.execute_notx(text("VACUUM ANALYZE claim;"))
p.step()
if p.ctx.is_postgres:
p.ctx.execute_notx(text("VACUUM ANALYZE tag;"))
p.step()
for constraint in pg_add_claim_and_tag_constraints_and_indexes:
if p.ctx.is_postgres:
@ -162,13 +162,11 @@ def claims_constraints_and_indexes(p: ProgressContext):
@event_emitter("blockchain.sync.claims.vacuum", "steps")
def claims_vacuum(p: ProgressContext):
p.start(2)
with p.ctx.engine.connect() as c:
if p.ctx.is_postgres:
c.execute(text("COMMIT;"))
c.execute(text("VACUUM claim;"))
p.ctx.execute_notx(text("VACUUM claim;"))
p.step()
if p.ctx.is_postgres:
c.execute(text("VACUUM tag;"))
p.ctx.execute_notx(text("VACUUM tag;"))
p.step()
@ -178,7 +176,7 @@ def claims_update(blocks: Tuple[int, int], p: ProgressContext):
count_unspent_txos(CLAIM_TYPE_CODES, blocks, missing_or_stale_in_claims_table=True),
progress_id=blocks[0], label=make_label("mod claims", blocks)
)
with p.ctx.engine.connect().execution_options(stream_results=True) as c:
with p.ctx.connect_streaming() as c:
loader = p.ctx.get_bulk_loader()
cursor = c.execute(select_claims_for_saving(
blocks, missing_or_stale_in_claims_table=True
@ -202,6 +200,7 @@ def claims_delete(claims, p: ProgressContext):
def update_takeovers(blocks: Tuple[int, int], takeovers, p: ProgressContext):
p.start(takeovers, label=make_label("mod winner", blocks))
chain = get_or_initialize_lbrycrd(p.ctx)
with p.ctx.engine.begin() as c:
for takeover in chain.db.sync_get_takeovers(start_height=blocks[0], end_height=blocks[-1]):
update_claims = (
Claim.update()
@ -218,7 +217,7 @@ def update_takeovers(blocks: Tuple[int, int], takeovers, p: ProgressContext):
activation_height=least(Claim.c.activation_height, takeover['height']),
)
)
result = p.ctx.execute(update_claims)
result = c.execute(update_claims)
p.add(result.rowcount)

10
lbry/blockchain/sync/supports.py
View file

@ -48,7 +48,7 @@ def supports_insert(blocks: Tuple[int, int], missing_in_supports_table: bool, p:
missing_in_supports_table=missing_in_supports_table,
)
)
with p.ctx.engine.connect().execution_options(stream_results=True) as c:
with p.ctx.connect_streaming() as c:
loader = p.ctx.get_bulk_loader()
for row in c.execute(select_supports):
txo = row_to_txo(row)
@ -74,9 +74,7 @@ def supports_delete(supports, p: ProgressContext):
def supports_constraints_and_indexes(p: ProgressContext):
p.start(1 + len(pg_add_support_constraints_and_indexes))
if p.ctx.is_postgres:
with p.ctx.engine.connect() as c:
c.execute(text("COMMIT;"))
c.execute(text("VACUUM ANALYZE support;"))
p.ctx.execute_notx(text("VACUUM ANALYZE support;"))
p.step()
for constraint in pg_add_support_constraints_and_indexes:
if p.ctx.is_postgres:
@ -87,8 +85,6 @@ def supports_constraints_and_indexes(p: ProgressContext):
@event_emitter("blockchain.sync.supports.vacuum", "steps")
def supports_vacuum(p: ProgressContext):
p.start(1)
with p.ctx.engine.connect() as c:
if p.ctx.is_postgres:
c.execute(text("COMMIT;"))
c.execute(text("VACUUM support;"))
p.ctx.execute_notx(text("VACUUM support;"))
p.step()

50
lbry/db/query_context.py
View file

@ -36,7 +36,6 @@ _context: ContextVar['QueryContext'] = ContextVar('_context')
@dataclass
class QueryContext:
engine: Engine
connection: Connection
ledger: Ledger
message_queue: mp.Queue
stop_event: mp.Event
@ -58,14 +57,14 @@ class QueryContext:
@property
def is_postgres(self):
return self.connection.dialect.name == 'postgresql'
return self.engine.dialect.name == 'postgresql'
@property
def is_sqlite(self):
return self.connection.dialect.name == 'sqlite'
return self.engine.dialect.name == 'sqlite'
def raise_unsupported_dialect(self):
raise RuntimeError(f'Unsupported database dialect: {self.connection.dialect.name}.')
raise RuntimeError(f'Unsupported database dialect: {self.engine.dialect.name}.')
def get_resolve_censor(self) -> Censor:
return Censor(self.blocked_streams, self.blocked_channels)
@ -74,24 +73,38 @@ class QueryContext:
return Censor(self.filtered_streams, self.filtered_channels)
def pg_copy(self, table, rows):
connection = self.connection.connection
with self.engine.begin() as c:
copy_manager = self.copy_managers.get(table.name)
if copy_manager is None:
self.copy_managers[table.name] = copy_manager = CopyManager(
self.connection.connection, table.name, rows[0].keys()
c.connection, table.name, rows[0].keys()
)
copy_manager.conn = c.connection
copy_manager.copy(map(dict.values, rows), BytesIO)
connection.commit()
copy_manager.conn = None
def connect_without_transaction(self):
return self.engine.connect().execution_options(isolation_level="AUTOCOMMIT")
def connect_streaming(self):
return self.engine.connect().execution_options(stream_results=True)
def execute_notx(self, sql, *args):
with self.connect_without_transaction() as c:
return c.execute(sql, *args)
def execute(self, sql, *args):
return self.connection.execute(sql, *args)
with self.engine.begin() as c:
return c.execute(sql, *args)
def fetchone(self, sql, *args):
row = self.connection.execute(sql, *args).fetchone()
with self.engine.begin() as c:
row = c.execute(sql, *args).fetchone()
return dict(row._mapping) if row else row
def fetchall(self, sql, *args):
rows = self.connection.execute(sql, *args).fetchall()
with self.engine.begin() as c:
rows = c.execute(sql, *args).fetchall()
return [dict(row._mapping) for row in rows]
def fetchtotal(self, condition) -> int:
@ -166,11 +179,17 @@ def set_postgres_settings(connection, _):
def set_sqlite_settings(connection, _):
connection.isolation_level = None
cursor = connection.cursor()
cursor.execute('PRAGMA journal_mode=WAL;')
cursor.close()
def do_sqlite_begin(connection):
# see: https://bit.ly/3j4vvXm
connection.exec_driver_sql("BEGIN")
def initialize(
ledger: Ledger, message_queue: mp.Queue, stop_event: mp.Event,
track_metrics=False, block_and_filter=None):
@ -180,15 +199,14 @@ def initialize(
sqlalchemy_event.listen(engine, "connect", set_postgres_settings)
elif engine.name == "sqlite":
sqlalchemy_event.listen(engine, "connect", set_sqlite_settings)
connection = engine.connect()
sqlalchemy_event.listen(engine, "begin", do_sqlite_begin)
if block_and_filter is not None:
blocked_streams, blocked_channels, filtered_streams, filtered_channels = block_and_filter
else:
blocked_streams = blocked_channels = filtered_streams = filtered_channels = {}
_context.set(
QueryContext(
pid=os.getpid(),
engine=engine, connection=connection,
pid=os.getpid(), engine=engine,
ledger=ledger, message_queue=message_queue, stop_event=stop_event,
stack=[], metrics={}, is_tracking_metrics=track_metrics,
blocked_streams=blocked_streams, blocked_channels=blocked_channels,
@ -200,9 +218,6 @@ def initialize(
def uninitialize():
ctx = _context.get(None)
if ctx is not None:
if ctx.connection:
ctx.connection.close()
if ctx.engine:
ctx.engine.dispose()
_context.set(None)
@ -664,7 +679,6 @@ class BulkLoader:
)
def flush(self, return_row_count_for_table) -> int:
execute = self.ctx.connection.execute
done = 0
for sql, rows in self.get_queries():
if not rows:
@ -672,7 +686,7 @@ class BulkLoader:
if self.ctx.is_postgres and isinstance(sql, Insert):
self.ctx.pg_copy(sql.table, rows)
else:
execute(sql, rows)
self.ctx.execute(sql, rows)
if sql.table == return_row_count_for_table:
done += len(rows)
rows.clear()

2
tests/integration/blockchain/test_blockchain.py
View file

@ -559,7 +559,7 @@ class TestMultiBlockFileSyncing(BasicBlockchainTestCase):
)
self.assertConsumingEvents(
events, "blockchain.sync.claims.indexes", ("steps",), [
(0, None, (7,), (1,), (2,), (3,), (4,), (5,), (6,), (7,))
(0, None, (8,), (1,), (2,), (3,), (4,), (5,), (6,), (7,), (8,))
]
)
self.assertEqual(