Change state fetch query for postgres to be faster

It turns out that postgres doesn't like doing a list of OR's and is
about 1000x slower, so we just issue a query for each specific type
seperately.
This commit is contained in:
Erik Johnston 2016-09-12 10:05:07 +01:00
parent 555460ae1b
commit 897d57bc58

View File

@ -306,13 +306,6 @@ class StateStore(SQLBaseStore):
defer.returnValue(results)
def _get_state_groups_from_groups_txn(self, txn, groups, types=None):
if types is not None:
where_clause = "AND (%s)" % (
" OR ".join(["(type = ? AND state_key = ?)"] * len(types)),
)
else:
where_clause = ""
results = {group: {} for group in groups}
if isinstance(self.database_engine, PostgresEngine):
# Temporarily disable sequential scans in this transaction. This is
@ -342,20 +335,43 @@ class StateStore(SQLBaseStore):
WHERE state_group IN (
SELECT state_group FROM state
)
%s;
""") % (where_clause,)
%s
""")
for group in groups:
args = [group]
if types is not None:
args.extend([i for typ in types for i in typ])
# Turns out that postgres doesn't like doing a list of OR's and
# is about 1000x slower, so we just issue a query for each specific
# type seperately.
if types:
clause_to_args = [
(
"AND type = ? AND state_key = ?",
(etype, state_key)
)
for etype, state_key in types
]
else:
# If types is None we fetch all the state, and so just use an
# empty where clause with no extra args.
clause_to_args = [("", [])]
txn.execute(sql, args)
rows = self.cursor_to_dict(txn)
for row in rows:
key = (row["type"], row["state_key"])
results[group][key] = row["event_id"]
for where_clause, where_args in clause_to_args:
for group in groups:
args = [group]
args.extend(where_args)
txn.execute(sql % (where_clause,), args)
rows = self.cursor_to_dict(txn)
for row in rows:
key = (row["type"], row["state_key"])
results[group][key] = row["event_id"]
else:
if types is not None:
where_clause = "AND (%s)" % (
" OR ".join(["(type = ? AND state_key = ?)"] * len(types)),
)
else:
where_clause = ""
# We don't use WITH RECURSIVE on sqlite3 as there are distributions
# that ship with an sqlite3 version that doesn't support it (e.g. wheezy)
for group in groups: