Fix missing _add_persisted_position (#8179)

This was forgotten in #8164.
pull/8187/head
Erik Johnston 2020-08-27 13:20:34 +01:00 committed by GitHub
parent 30426c7063
commit 5649b7f3d0
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3 changed files with 52 additions and 3 deletions

1
changelog.d/8179.misc Normal file
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@ -0,0 +1 @@
Add functions to `MultiWriterIdGen` used by events stream.

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@ -343,6 +343,8 @@ class MultiWriterIdGenerator:
curr = self._current_positions.get(self._instance_name, 0)
self._current_positions[self._instance_name] = max(curr, next_id)
self._add_persisted_position(next_id)
def get_current_token(self) -> int:
"""Returns the maximum stream id such that all stream ids less than or
equal to it have been successfully persisted.

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@ -58,6 +58,10 @@ class MultiWriterIdGeneratorTestCase(HomeserverTestCase):
return self.get_success(self.db_pool.runWithConnection(_create))
def _insert_rows(self, instance_name: str, number: int):
"""Insert N rows as the given instance, inserting with stream IDs pulled
from the postgres sequence.
"""
def _insert(txn):
for _ in range(number):
txn.execute(
@ -65,7 +69,20 @@ class MultiWriterIdGeneratorTestCase(HomeserverTestCase):
(instance_name,),
)
self.get_success(self.db_pool.runInteraction("test_single_instance", _insert))
self.get_success(self.db_pool.runInteraction("_insert_rows", _insert))
def _insert_row_with_id(self, instance_name: str, stream_id: int):
"""Insert one row as the given instance with given stream_id, updating
the postgres sequence position to match.
"""
def _insert(txn):
txn.execute(
"INSERT INTO foobar VALUES (?, ?)", (stream_id, instance_name,),
)
txn.execute("SELECT setval('foobar_seq', ?)", (stream_id,))
self.get_success(self.db_pool.runInteraction("_insert_row_with_id", _insert))
def test_empty(self):
"""Test an ID generator against an empty database gives sensible
@ -188,11 +205,17 @@ class MultiWriterIdGeneratorTestCase(HomeserverTestCase):
positions.
"""
self._insert_rows("first", 3)
self._insert_rows("second", 5)
# The following tests are a bit cheeky in that we notify about new
# positions via `advance` without *actually* advancing the postgres
# sequence.
self._insert_row_with_id("first", 3)
self._insert_row_with_id("second", 5)
id_gen = self._create_id_generator("first")
self.assertEqual(id_gen.get_positions(), {"first": 3, "second": 5})
# Min is 3 and there is a gap between 5, so we expect it to be 3.
self.assertEqual(id_gen.get_persisted_upto_position(), 3)
@ -218,3 +241,26 @@ class MultiWriterIdGeneratorTestCase(HomeserverTestCase):
id_gen.advance("first", 11)
id_gen.advance("second", 15)
self.assertEqual(id_gen.get_persisted_upto_position(), 11)
def test_get_persisted_upto_position_get_next(self):
"""Test that `get_persisted_upto_position` correctly tracks updates to
positions when `get_next` is called.
"""
self._insert_row_with_id("first", 3)
self._insert_row_with_id("second", 5)
id_gen = self._create_id_generator("first")
self.assertEqual(id_gen.get_positions(), {"first": 3, "second": 5})
self.assertEqual(id_gen.get_persisted_upto_position(), 3)
with self.get_success(id_gen.get_next()) as stream_id:
self.assertEqual(stream_id, 6)
self.assertEqual(id_gen.get_persisted_upto_position(), 3)
self.assertEqual(id_gen.get_persisted_upto_position(), 6)
# We assume that so long as `get_next` does correctly advance the
# `persisted_upto_position` in this case, then it will be correct in the
# other cases that are tested above (since they'll hit the same code).