forked from hans/Nominatim
factor out async connection handling into separate class
Also adds a test for reconnecting regularly while indexing.
This commit is contained in:
Sarah Hoffmann
@@ -11,6 +11,68 @@ from nominatim.db.connection import connect
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LOG = logging.getLogger()
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class WorkerPool:
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""" A pool of asynchronous database connections.
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The pool may be used as a context manager.
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"""
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REOPEN_CONNECTIONS_AFTER = 100000
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def __init__(self, dsn, pool_size):
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self.threads = [DBConnection(dsn) for _ in range(pool_size)]
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self.free_workers = self._yield_free_worker()
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def finish_all(self):
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""" Wait for all connection to finish.
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"""
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for thread in self.threads:
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while not thread.is_done():
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thread.wait()
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self.free_workers = self._yield_free_worker()
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def close(self):
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""" Close all connections and clear the pool.
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"""
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for thread in self.threads:
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thread.close()
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self.threads = []
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self.free_workers = None
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def next_free_worker(self):
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""" Get the next free connection.
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"""
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return next(self.free_workers)
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def _yield_free_worker(self):
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ready = self.threads
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command_stat = 0
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while True:
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for thread in ready:
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if thread.is_done():
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command_stat += 1
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yield thread
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if command_stat > self.REOPEN_CONNECTIONS_AFTER:
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for thread in self.threads:
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while not thread.is_done():
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thread.wait()
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thread.connect()
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ready = self.threads
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else:
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_, ready, _ = select.select([], self.threads, [])
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def __enter__(self):
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return self
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def __exit__(self, exc_type, exc_value, traceback):
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self.close()
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class Indexer:
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""" Main indexing routine.
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@@ -19,17 +81,6 @@ class Indexer:
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def __init__(self, dsn, num_threads):
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self.dsn = dsn
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self.num_threads = num_threads
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self.threads = []
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def _setup_connections(self):
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self.threads = [DBConnection(self.dsn) for _ in range(self.num_threads)]
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def _close_connections(self):
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for thread in self.threads:
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thread.close()
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self.threads = []
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def index_full(self, analyse=True):
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@@ -42,27 +93,27 @@ class Indexer:
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conn.autocommit = True
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if analyse:
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def _analyse():
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def _analyze():
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with conn.cursor() as cur:
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cur.execute('ANALYSE')
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cur.execute('ANALYZE')
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else:
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def _analyse():
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def _analyze():
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pass
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self.index_by_rank(0, 4)
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_analyse()
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_analyze()
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self.index_boundaries(0, 30)
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_analyse()
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_analyze()
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self.index_by_rank(5, 25)
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_analyse()
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_analyze()
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self.index_by_rank(26, 30)
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_analyse()
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_analyze()
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self.index_postcodes()
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_analyse()
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_analyze()
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def index_boundaries(self, minrank, maxrank):
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@@ -71,13 +122,8 @@ class Indexer:
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LOG.warning("Starting indexing boundaries using %s threads",
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self.num_threads)
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self._setup_connections()
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try:
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for rank in range(max(minrank, 4), min(maxrank, 26)):
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self._index(runners.BoundaryRunner(rank))
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finally:
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self._close_connections()
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for rank in range(max(minrank, 4), min(maxrank, 26)):
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self._index(runners.BoundaryRunner(rank))
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def index_by_rank(self, minrank, maxrank):
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""" Index all entries of placex in the given rank range (inclusive)
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@@ -90,20 +136,15 @@ class Indexer:
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LOG.warning("Starting indexing rank (%i to %i) using %i threads",
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minrank, maxrank, self.num_threads)
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self._setup_connections()
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for rank in range(max(1, minrank), maxrank):
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self._index(runners.RankRunner(rank))
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try:
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for rank in range(max(1, minrank), maxrank):
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self._index(runners.RankRunner(rank))
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if maxrank == 30:
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self._index(runners.RankRunner(0))
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self._index(runners.InterpolationRunner(), 20)
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self._index(runners.RankRunner(30), 20)
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else:
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self._index(runners.RankRunner(maxrank))
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finally:
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self._close_connections()
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if maxrank == 30:
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self._index(runners.RankRunner(0))
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self._index(runners.InterpolationRunner(), 20)
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self._index(runners.RankRunner(30), 20)
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else:
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self._index(runners.RankRunner(maxrank))
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def index_postcodes(self):
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@@ -111,12 +152,8 @@ class Indexer:
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"""
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LOG.warning("Starting indexing postcodes using %s threads", self.num_threads)
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self._setup_connections()
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self._index(runners.PostcodeRunner(), 20)
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try:
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self._index(runners.PostcodeRunner(), 20)
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finally:
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self._close_connections()
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def update_status_table(self):
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""" Update the status in the status table to 'indexed'.
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@@ -147,48 +184,20 @@ class Indexer:
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with conn.cursor(name='places') as cur:
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cur.execute(runner.sql_get_objects())
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next_thread = self.find_free_thread()
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while True:
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places = [p[0] for p in cur.fetchmany(batch)]
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if not places:
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break
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with WorkerPool(self.dsn, self.num_threads) as pool:
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while True:
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places = [p[0] for p in cur.fetchmany(batch)]
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if not places:
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break
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LOG.debug("Processing places: %s", str(places))
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thread = next(next_thread)
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LOG.debug("Processing places: %s", str(places))
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worker = pool.next_free_worker()
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thread.perform(runner.sql_index_place(places))
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progress.add(len(places))
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worker.perform(runner.sql_index_place(places))
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progress.add(len(places))
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conn.commit()
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pool.finish_all()
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for thread in self.threads:
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thread.wait()
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conn.commit()
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progress.done()
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def find_free_thread(self):
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""" Generator that returns the next connection that is free for
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sending a query.
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"""
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ready = self.threads
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command_stat = 0
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while True:
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for thread in ready:
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if thread.is_done():
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command_stat += 1
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yield thread
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# refresh the connections occasionaly to avoid potential
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# memory leaks in Postgresql.
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if command_stat > 100000:
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for thread in self.threads:
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while not thread.is_done():
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thread.wait()
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thread.connect()
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command_stat = 0
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ready = self.threads
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else:
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ready, _, _ = select.select(self.threads, [], [])
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assert False, "Unreachable code"
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