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1650 lines (1506 loc) · 56.5 KB
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"""Test the PooledDB module.
Note:
We don't test performance here, so the test does not predicate
whether PooledDB actually will help in improving performance or not.
We also assume that the underlying SteadyDB connections are tested.
Copyright and credit info:
* This test was contributed by Christoph Zwerschke
"""
from queue import Empty, Queue
from threading import Thread
import pytest
from dbutils.pooled_db import (
InvalidConnectionError,
NotSupportedError,
PooledDB,
SharedDBConnection,
TooManyConnectionsError,
)
from dbutils.steady_db import SteadyDBConnection
def test_version():
"""Check that the module and class versions are in sync."""
from dbutils import __version__, pooled_db
assert pooled_db.__version__ == __version__
assert PooledDB.version == __version__
@pytest.mark.parametrize("threadsafety", [None, 0])
def test_no_threadsafety(dbapi, threadsafety):
"""Check that a database module that is not thread-safe is rejected."""
dbapi.threadsafety = threadsafety
with pytest.raises(NotSupportedError):
PooledDB(dbapi)
def test_creator_function(dbapi):
"""Check that a creator function can be used instead of a module."""
pool = PooledDB(dbapi.connect, 1, database='ok')
# the threadsafety cannot be determined from a plain creator function,
# so the connections are optimistically assumed to be thread-safe,
# but not safe enough to be shared between several threads
assert pool._maxshared == 0
db = pool.connection()
assert db.threadsafety() == dbapi.threadsafety
cursor = db.cursor()
cursor.execute('select test')
assert cursor.fetchone() == 'test'
def test_creator_without_threadsafety(dbapi):
"""Check that a creator that hides its threadsafety is rejected."""
class Creator:
"""A database module that does not report its threadsafety."""
connect = staticmethod(dbapi.connect)
with pytest.raises(NotSupportedError):
PooledDB(Creator)
def test_creator_with_unsafe_connections(dbapi, monkeypatch):
"""Check that connections that are not thread-safe are rejected."""
monkeypatch.delattr(dbapi, 'threadsafety')
# the pool optimistically assumes that a creator function provides
# thread-safe connections, but the connections themselves know better
pool = PooledDB(dbapi.connect, 0)
with pytest.raises(NotSupportedError):
pool.connection()
@pytest.mark.parametrize("threadsafety", [1, 2, 3])
def test_threadsafety(dbapi, threadsafety):
"""Check that connections are only shared when they may be."""
dbapi.threadsafety = threadsafety
pool = PooledDB(dbapi, 0, 0, 1)
assert hasattr(pool, '_maxshared')
if threadsafety > 1:
assert pool._maxshared == 1
assert hasattr(pool, '_shared_cache')
else:
assert pool._maxshared == 0
assert not hasattr(pool, '_shared_cache')
@pytest.mark.parametrize("threadsafety", [1, 2])
def test_create_connection(dbapi, threadsafety):
"""Check that the pool creates connections with the given parameters."""
dbapi.threadsafety = threadsafety
shareable = threadsafety > 1
pool = PooledDB(
dbapi, 1, 1, 1, 0, False, None, None, True, None, None, None,
'PooledDBTestDB', user='PooledDBTestUser')
# mincached=1, so one connection has been created up front
assert hasattr(pool, '_idle_cache')
assert len(pool._idle_cache) == 1
if shareable:
assert hasattr(pool, '_shared_cache')
assert len(pool._shared_cache) == 0
else:
assert not hasattr(pool, '_shared_cache')
assert hasattr(pool, '_maxusage')
assert pool._maxusage is None
assert hasattr(pool, '_setsession')
assert pool._setsession is None
# the cached connection is a steady connection without extra settings
con = pool._idle_cache[0]
assert isinstance(con, SteadyDBConnection)
assert hasattr(con, '_maxusage')
assert con._maxusage == 0
assert hasattr(con, '_setsession_sql')
assert con._setsession_sql is None
# taking it out of the pool moves it from the idle to the shared cache
db = pool.connection()
assert len(pool._idle_cache) == 0
if shareable:
assert len(pool._shared_cache) == 1
assert hasattr(db, '_con')
assert db._con == con
assert hasattr(db, 'cursor')
assert hasattr(db, '_usage')
assert db._usage == 0
# the connect parameters have been passed down to the DB-API 2 connection
assert hasattr(con, '_con')
db_con = con._con
assert hasattr(db_con, 'database')
assert db_con.database == 'PooledDBTestDB'
assert hasattr(db_con, 'user')
assert db_con.user == 'PooledDBTestUser'
assert hasattr(db_con, 'open_cursors')
assert db_con.open_cursors == 0
assert hasattr(db_con, 'num_uses')
assert db_con.num_uses == 0
assert hasattr(db_con, 'num_queries')
assert db_con.num_queries == 0
# a query opens and closes a cursor and counts as one query and one use
cursor = db.cursor()
assert db_con.open_cursors == 1
cursor.execute('select test')
r = cursor.fetchone()
cursor.close()
assert db_con.open_cursors == 0
assert r == 'test'
assert db_con.num_queries == 1
assert db._usage == 1
# two cursors can be open at the same time on the same connection,
# and a "set" command is recorded in the session instead of as a query
cursor = db.cursor()
assert db_con.open_cursors == 1
cursor.execute('set sessiontest')
cursor2 = db.cursor()
assert db_con.open_cursors == 2
cursor2.close()
assert db_con.open_cursors == 1
cursor.close()
assert db_con.open_cursors == 0
assert db_con.num_queries == 1
assert db._usage == 2
assert db_con.session == ['rollback', 'sessiontest']
@pytest.mark.parametrize("threadsafety", [1, 2])
def test_dedicated_connection(dbapi, threadsafety):
"""Check the difference between shared and dedicated connections."""
dbapi.threadsafety = threadsafety
shareable = threadsafety > 1
pool = PooledDB(dbapi, 1, 1, 1)
assert len(pool._idle_cache) == 1
if shareable:
assert len(pool._shared_cache) == 0
# connection() defaults to a shared connection
db = pool.connection()
assert len(pool._idle_cache) == 0
if shareable:
assert len(pool._shared_cache) == 1
db.close()
assert len(pool._idle_cache) == 1
if shareable:
assert len(pool._shared_cache) == 0
# asking for a shared connection explicitly does the same
db = pool.connection(True)
assert len(pool._idle_cache) == 0
if shareable:
assert len(pool._shared_cache) == 1
db.close()
assert len(pool._idle_cache) == 1
if shareable:
assert len(pool._shared_cache) == 0
# a dedicated connection never enters the shared cache
db = pool.connection(False)
assert len(pool._idle_cache) == 0
if shareable:
assert len(pool._shared_cache) == 0
assert db._usage == 0
db_con = db._con._con
assert db_con.database is None
assert db_con.user is None
db.close()
assert len(pool._idle_cache) == 1
if shareable:
assert len(pool._shared_cache) == 0
# dedicated_connection() is a shortcut for connection(False)
db = pool.dedicated_connection()
assert len(pool._idle_cache) == 0
if shareable:
assert len(pool._shared_cache) == 0
assert db._usage == 0
db_con = db._con._con
assert db_con.database is None
assert db_con.user is None
db.close()
assert len(pool._idle_cache) == 1
if shareable:
assert len(pool._shared_cache) == 0
def test_create_connection_with_settings(dbapi):
"""Check that maxusage and setsession are passed on to the connections."""
pool = PooledDB(dbapi, 0, 0, 0, 0, False, 3, ('set datestyle',))
assert pool._maxusage == 3
assert pool._setsession == ('set datestyle',)
con = pool.connection()._con
assert con._maxusage == 3
assert con._setsession_sql == ('set datestyle',)
@pytest.mark.parametrize("threadsafety", [1, 2])
def test_close_connection(dbapi, threadsafety):
"""Check that a closed connection is returned to the pool."""
dbapi.threadsafety = threadsafety
shareable = threadsafety > 1
pool = PooledDB(
dbapi, 0, 1, 1, 0, False, None, None, True, None, None, None,
'PooledDBTestDB', user='PooledDBTestUser')
assert hasattr(pool, '_idle_cache')
assert len(pool._idle_cache) == 0
# take a connection out of the pool and note its underlying connection
db = pool.connection()
assert hasattr(db, '_con')
con = db._con
assert len(pool._idle_cache) == 0
if shareable:
assert len(pool._shared_cache) == 1
assert hasattr(db, '_shared_con')
shared_con = db._shared_con
assert pool._shared_cache[0] == shared_con
assert hasattr(shared_con, 'shared')
assert shared_con.shared == 1
assert hasattr(shared_con, 'con')
assert shared_con.con == con
assert isinstance(con, SteadyDBConnection)
assert hasattr(con, '_con')
db_con = con._con
assert hasattr(db_con, 'num_queries')
assert db._usage == 0
assert db_con.num_queries == 0
db.cursor().execute('select test')
assert db._usage == 1
assert db_con.num_queries == 1
# closing the pooled connection invalidates it, but returns the
# underlying connection to the idle cache instead of closing it
db.close()
assert db._con is None
if shareable:
assert db._shared_con is None
assert shared_con.shared == 0
with pytest.raises(InvalidConnectionError):
assert db._usage
assert not hasattr(db_con, '_num_queries')
assert len(pool._idle_cache) == 1
assert pool._idle_cache[0]._con == db_con
if shareable:
assert len(pool._shared_cache) == 0
# closing it a second time is a no-op
db.close()
if shareable:
assert shared_con.shared == 0
# the next request gets the same underlying connection back,
# with its usage counters and connect parameters still intact
db = pool.connection()
assert db._con == con
assert len(pool._idle_cache) == 0
if shareable:
assert len(pool._shared_cache) == 1
shared_con = db._shared_con
assert pool._shared_cache[0] == shared_con
assert shared_con.con == con
assert shared_con.shared == 1
assert db._usage == 1
assert db_con.num_queries == 1
assert hasattr(db_con, 'database')
assert db_con.database == 'PooledDBTestDB'
assert hasattr(db_con, 'user')
assert db_con.user == 'PooledDBTestUser'
db.cursor().execute('select test')
assert db_con.num_queries == 2
db.cursor().execute('select test')
assert db_con.num_queries == 3
db.close()
assert len(pool._idle_cache) == 1
assert pool._idle_cache[0]._con == db_con
if shareable:
assert len(pool._shared_cache) == 0
# a dedicated connection is returned to the idle cache as well
db = pool.connection(False)
assert db._con == con
assert len(pool._idle_cache) == 0
if shareable:
assert len(pool._shared_cache) == 0
db.close()
assert len(pool._idle_cache) == 1
if shareable:
assert len(pool._shared_cache) == 0
def test_close_all(dbapi):
"""Check that closing the pool empties the idle cache."""
pool = PooledDB(dbapi, 10)
assert len(pool._idle_cache) == 10
pool.close()
assert len(pool._idle_cache) == 0
def test_close_all_when_pool_is_deleted(dbapi):
"""Check that deleting the pool closes the cached connections."""
pool = PooledDB(dbapi, 10)
closed = ['no']
def close(what=closed):
what[0] = 'yes'
pool._idle_cache[7]._con.close = close
assert closed == ['no']
del pool
assert closed == ['yes']
@pytest.mark.parametrize("threadsafety", [1, 2])
def test_close_all_shared(dbapi, threadsafety):
"""Check that closing the pool empties the shared cache as well."""
dbapi.threadsafety = threadsafety
shareable = threadsafety > 1
pool = PooledDB(dbapi, 10, 10, 5)
assert len(pool._idle_cache) == 10
if shareable:
assert len(pool._shared_cache) == 0
cache = []
for _i in range(5):
cache.append(pool.connection())
assert len(pool._idle_cache) == 5
if shareable:
assert len(pool._shared_cache) == 5
pool.close()
assert len(pool._idle_cache) == 0
if shareable:
assert len(pool._shared_cache) == 0
@pytest.mark.parametrize("threadsafety", [1, 2])
def test_close_all_shared_when_pool_is_deleted(dbapi, threadsafety):
"""Check that deleting the pool closes idle and shared connections."""
dbapi.threadsafety = threadsafety
shareable = threadsafety > 1
pool = PooledDB(dbapi, 10, 10, 5)
closed = []
def close_idle(what=closed):
what.append('idle')
def close_shared(what=closed):
what.append('shared')
# spy on one idle and one shared connection (or, when connections
# cannot be shared, on a second idle connection closed after the first)
if shareable:
cache = []
for _i in range(5):
cache.append(pool.connection())
pool._shared_cache[3].con.close = close_shared
else:
pool._idle_cache[7]._con.close = close_shared
pool._idle_cache[3]._con.close = close_idle
assert closed == []
del pool
if shareable:
del cache
assert closed == ['idle', 'shared']
@pytest.mark.parametrize("threadsafety", [1, 2])
def test_shareable_connection(dbapi, threadsafety):
"""Check that connections are shared when the maximum is reached."""
dbapi.threadsafety = threadsafety
shareable = threadsafety > 1
pool = PooledDB(dbapi, 0, 1, 2)
assert len(pool._idle_cache) == 0
if shareable:
assert len(pool._shared_cache) == 0
# the first two requests get connections of their own
db1 = pool.connection()
assert len(pool._idle_cache) == 0
if shareable:
assert len(pool._shared_cache) == 1
db2 = pool.connection()
assert db1._con != db2._con
assert len(pool._idle_cache) == 0
if shareable:
assert len(pool._shared_cache) == 2
# maxshared is reached now, so the next requests share those connections
db3 = pool.connection()
assert len(pool._idle_cache) == 0
if shareable:
assert len(pool._shared_cache) == 2
assert db3._con == db1._con
assert db1._shared_con.shared == 2
assert db2._shared_con.shared == 1
else:
assert db3._con != db1._con
assert db3._con != db2._con
db4 = pool.connection()
assert len(pool._idle_cache) == 0
if shareable:
assert len(pool._shared_cache) == 2
assert db4._con == db2._con
assert db1._shared_con.shared == 2
assert db2._shared_con.shared == 2
else:
assert db4._con != db1._con
assert db4._con != db2._con
assert db4._con != db3._con
# a dedicated connection is never taken from the shared cache
db5 = pool.connection(False)
assert db5._con != db1._con
assert db5._con != db2._con
assert db5._con != db3._con
assert db5._con != db4._con
assert len(pool._idle_cache) == 0
if shareable:
assert len(pool._shared_cache) == 2
assert db1._shared_con.shared == 2
assert db2._shared_con.shared == 2
# and once returned it stays in the idle cache,
# since a shareable request prefers to share an existing connection
db5.close()
assert len(pool._idle_cache) == 1
db5 = pool.connection()
if shareable:
assert len(pool._idle_cache) == 1
assert len(pool._shared_cache) == 2
assert db5._shared_con.shared == 3
else:
assert len(pool._idle_cache) == 0
@pytest.mark.parametrize("threadsafety", [1, 2])
def test_unshare_connection(dbapi, threadsafety):
"""Check that a shared connection is cached again when fully unshared."""
dbapi.threadsafety = threadsafety
shareable = threadsafety > 1
pool = PooledDB(dbapi, 0, 0, 1)
assert len(pool._idle_cache) == 0
db1 = pool.connection(False)
if shareable:
assert len(pool._shared_cache) == 0
db2 = pool.connection()
if shareable:
assert len(pool._shared_cache) == 1
db3 = pool.connection()
if shareable:
assert len(pool._shared_cache) == 1
assert db2._con == db3._con
else:
assert db2._con != db3._con
# dropping one of the two sharers leaves the connection shared once,
# so it is not cached as idle yet
del db3
if shareable:
assert len(pool._idle_cache) == 0
assert len(pool._shared_cache) == 1
else:
assert len(pool._idle_cache) == 1
# dropping the last sharer moves it back to the idle cache
del db2
if shareable:
assert len(pool._idle_cache) == 1
assert len(pool._shared_cache) == 0
else:
assert len(pool._idle_cache) == 2
del db1
if shareable:
assert len(pool._idle_cache) == 2
assert len(pool._shared_cache) == 0
else:
assert len(pool._idle_cache) == 3
@pytest.mark.parametrize("threadsafety", [1, 2])
@pytest.mark.parametrize(("mincached", "maxcached", "cached", "rounds"), [
# every round takes the given number of connections out of the pool
# and expects the given number of idle connections after releasing them
(3, 0, 3, [(3, 3), (6, 6)]), # unlimited cache grows with the demand
(3, None, 3, [(3, 3), (6, 6)]), # None is the same as zero here
(None, None, 0, [(3, 3), (6, 6)]), # and also when nothing is cached
(0, 3, 0, [(3, 3), (6, 3)]), # cache fills up to maxcached
(3, 3, 3, [(3, 3), (6, 3)]), # cache stays at the common bound
(3, 2, 3, [(4, 3)]), # mincached wins when it exceeds maxcached
(2, 5, 2, [(10, 5)]), # cache grows from mincached to maxcached
])
def test_min_max_cached(dbapi, threadsafety,
mincached, maxcached, cached, rounds):
"""Check that the idle cache is kept between the given bounds."""
dbapi.threadsafety = threadsafety
pool = PooledDB(dbapi, mincached, maxcached)
assert len(pool._idle_cache) == cached
for taken, cached_again in rounds:
cache = [pool.connection() for _i in range(taken)]
assert len(pool._idle_cache) == 0
assert cache
del cache
assert len(pool._idle_cache) == cached_again
@pytest.mark.parametrize("threadsafety", [1, 2])
def test_min_max_cached_with_shared(dbapi, threadsafety):
"""Check the idle cache bounds when connections can also be shared."""
dbapi.threadsafety = threadsafety
shareable = threadsafety > 1
pool = PooledDB(dbapi, 1, 2, 3)
assert len(pool._idle_cache) == 1
# dedicated connections are cached up to maxcached when released
cache = [pool.connection(False) for _i in range(4)]
assert len(pool._idle_cache) == 0
if shareable:
assert len(pool._shared_cache) == 0
assert cache
del cache
assert len(pool._idle_cache) == 2
# shared connections do not touch the idle cache while they are in use
cache = [pool.connection() for _i in range(10)]
assert len(pool._idle_cache) == 0
if shareable:
assert len(pool._shared_cache) == 3
assert cache
del cache
assert len(pool._idle_cache) == 2
if shareable:
assert len(pool._shared_cache) == 0
@pytest.mark.parametrize("threadsafety", [1, 2])
def test_min_max_cached_with_fewer_shared(dbapi, threadsafety):
"""Check the idle cache bounds when maxshared is below maxcached."""
dbapi.threadsafety = threadsafety
shareable = threadsafety > 1
pool = PooledDB(dbapi, 1, 3, 2)
assert len(pool._idle_cache) == 1
cache = [pool.connection(False) for _i in range(4)]
assert len(pool._idle_cache) == 0
if shareable:
assert len(pool._shared_cache) == 0
assert cache
del cache
assert len(pool._idle_cache) == 3
# only maxshared connections are needed, so one stays in the idle cache
cache = [pool.connection() for _i in range(10)]
if shareable:
assert len(pool._idle_cache) == 1
assert len(pool._shared_cache) == 2
else:
assert len(pool._idle_cache) == 0
assert cache
del cache
assert len(pool._idle_cache) == 3
if shareable:
assert len(pool._shared_cache) == 0
@pytest.mark.parametrize("threadsafety", [1, 2])
def test_max_shared(dbapi, threadsafety):
"""Check that the maximum number of shared connections is not exceeded."""
dbapi.threadsafety = threadsafety
shareable = threadsafety > 1
pool = PooledDB(dbapi)
assert len(pool._idle_cache) == 0
cache = [pool.connection() for _i in range(10)]
assert len(cache) == 10
assert len(pool._idle_cache) == 0
pool = PooledDB(dbapi, 1, 1, 0)
assert len(pool._idle_cache) == 1
cache = [pool.connection() for _i in range(10)]
assert len(cache) == 10
assert len(pool._idle_cache) == 0
pool = PooledDB(dbapi, 0, 0, 1)
cache = [pool.connection() for _i in range(10)]
assert len(cache) == 10
assert len(pool._idle_cache) == 0
if shareable:
assert len(pool._shared_cache) == 1
pool = PooledDB(dbapi, 1, 1, 1)
assert len(pool._idle_cache) == 1
cache = [pool.connection() for _i in range(10)]
assert len(cache) == 10
assert len(pool._idle_cache) == 0
if shareable:
assert len(pool._shared_cache) == 1
pool = PooledDB(dbapi, 0, 0, 7)
cache = [pool.connection(False) for _i in range(3)]
assert len(cache) == 3
assert len(pool._idle_cache) == 0
if shareable:
assert len(pool._shared_cache) == 0
cache = [pool.connection() for _i in range(10)]
assert len(cache) == 10
assert len(pool._idle_cache) == 3
if shareable:
assert len(pool._shared_cache) == 7
def test_sort_shared(dbapi):
"""Check that shared connections are sorted by transaction and shares."""
pool = PooledDB(dbapi, 0, 4, 4)
cache = []
for _i in range(6):
db = pool.connection()
db.cursor().execute('select test')
cache.append(db)
for i, db in enumerate(cache):
assert db._shared_con.shared == 1 if 2 <= i < 4 else 2
cache[2].begin()
cache[3].begin()
db = pool.connection()
assert db._con is cache[0]._con
db.close()
cache[3].rollback()
db = pool.connection()
assert db._con is cache[3]._con
@pytest.mark.parametrize("threadsafety", [1, 2])
def test_equally_shared(dbapi, threadsafety):
"""Check that the load is spread equally over the connections."""
dbapi.threadsafety = threadsafety
shareable = threadsafety > 1
pool = PooledDB(dbapi, 5, 5, 5)
assert len(pool._idle_cache) == 5
for _i in range(15):
db = pool.connection(False)
db.cursor().execute('select test')
db.close()
assert len(pool._idle_cache) == 5
for i in range(5):
con = pool._idle_cache[i]
assert con._usage == 3
assert con._con.num_queries == 3
cache = []
for _i in range(35):
db = pool.connection()
db.cursor().execute('select test')
cache.append(db)
del db
assert len(pool._idle_cache) == 0
if shareable:
assert len(pool._shared_cache) == 5
for i in range(5):
con = pool._shared_cache[i]
assert con.shared == 7
con = con.con
assert con._usage == 10
assert con._con.num_queries == 10
del cache
assert len(pool._idle_cache) == 5
if shareable:
assert len(pool._shared_cache) == 0
@pytest.mark.parametrize("threadsafety", [1, 2])
def test_many_shared(dbapi, threadsafety):
"""Check that many shared connections are counted correctly."""
dbapi.threadsafety = threadsafety
shareable = threadsafety > 1
pool = PooledDB(dbapi, 0, 0, 5)
# 35 requests are spread evenly over the 5 shareable connections,
# each of which then carries 7 shares and 3 uses per share
cache = []
for _i in range(35):
db = pool.connection()
db.cursor().execute('select test1')
db.cursor().execute('select test2')
db.cursor().callproc('test3')
cache.append(db)
del db
assert len(pool._idle_cache) == 0
if shareable:
assert len(pool._shared_cache) == 5
for i in range(5):
con = pool._shared_cache[i]
assert con.shared == 7
con = con.con
assert con._usage == 21
assert con._con.num_queries == 14
# dropping 6 of the requests unshares the connections unevenly,
# and re-sorts the cache so that the least shared one comes first
cache[3] = cache[8] = cache[33] = None
cache[12] = cache[17] = cache[34] = None
assert len(pool._shared_cache) == 5
assert pool._shared_cache[0].shared == 7
assert pool._shared_cache[1].shared == 7
assert pool._shared_cache[2].shared == 5
assert pool._shared_cache[3].shared == 4
assert pool._shared_cache[4].shared == 6
# 6 new requests fill up the gaps, so the load is balanced again
for db in cache:
if db:
db.cursor().callproc('test4')
for _i in range(6):
db = pool.connection()
db.cursor().callproc('test4')
cache.append(db)
del db
for i in range(5):
con = pool._shared_cache[i]
assert con.shared == 7
con = con.con
assert con._usage == 28
assert con._con.num_queries == 14
del cache
if shareable:
assert len(pool._idle_cache) == 5
assert len(pool._shared_cache) == 0
else:
assert len(pool._idle_cache) == 35
@pytest.mark.parametrize("threadsafety", [1, 2])
def test_rollback(dbapi, threadsafety):
"""Check that connections are rolled back when returned to the pool."""
dbapi.threadsafety = threadsafety
pool = PooledDB(dbapi, 0, 1)
assert len(pool._idle_cache) == 0
db = pool.connection(False)
assert len(pool._idle_cache) == 0
assert db._con._con.open_cursors == 0
cursor = db.cursor()
assert db._con._con.open_cursors == 1
cursor.execute('set doit1')
db.commit()
cursor.execute('set dont1')
cursor.close()
assert db._con._con.open_cursors == 0
del db
assert len(pool._idle_cache) == 1
db = pool.connection(False)
assert len(pool._idle_cache) == 0
assert db._con._con.open_cursors == 0
cursor = db.cursor()
assert db._con._con.open_cursors == 1
cursor.execute('set doit2')
cursor.close()
assert db._con._con.open_cursors == 0
db.commit()
session = db._con._con.session
db.close()
assert session == [
'doit1', 'commit', 'dont1', 'rollback',
'doit2', 'commit', 'rollback']
@pytest.mark.parametrize("threadsafety", [1, 2])
def test_maxconnections(dbapi, threadsafety):
"""Check that the maximum number of connections is enforced."""
dbapi.threadsafety = threadsafety
shareable = threadsafety > 1
pool = PooledDB(dbapi, 1, 2, 2, 3)
assert hasattr(pool, '_maxconnections')
assert pool._maxconnections == 3
assert hasattr(pool, '_connections')
assert pool._connections == 0
assert len(pool._idle_cache) == 1
# three dedicated connections exhaust the pool
cache = []
for _i in range(3):
cache.append(pool.connection(False))
assert pool._connections == 3
assert len(pool._idle_cache) == 0
if shareable:
assert len(pool._shared_cache) == 0
with pytest.raises(TooManyConnectionsError):
pool.connection(False)
with pytest.raises(TooManyConnectionsError):
pool.connection()
# releasing them frees the pool again (only maxcached=2 are kept)
cache = []
assert pool._connections == 0
assert len(pool._idle_cache) == 2
if shareable:
assert len(pool._shared_cache) == 0
# three shareable connections only need maxshared=2 connections,
# which leaves room for one more dedicated connection
for _i in range(3):
cache.append(pool.connection())
assert len(pool._idle_cache) == 0
if shareable:
assert pool._connections == 2
assert len(pool._shared_cache) == 2
cache.append(pool.connection(False))
assert pool._connections == 3
assert len(pool._shared_cache) == 2
else:
assert pool._connections == 3
with pytest.raises(TooManyConnectionsError):
pool.connection(False)
# further shareable requests are always served by sharing
if shareable:
cache.append(pool.connection(True))
assert pool._connections == 3
else:
with pytest.raises(TooManyConnectionsError):
pool.connection()
del cache
assert pool._connections == 0
assert len(pool._idle_cache) == 2
@pytest.mark.parametrize("threadsafety", [1, 2])
def test_maxconnections_one(dbapi, threadsafety):
"""Check that a pool can be limited to a single connection."""
dbapi.threadsafety = threadsafety
shareable = threadsafety > 1
pool = PooledDB(dbapi, 0, 1, 1, 1)
assert pool._maxconnections == 1
assert pool._connections == 0
assert len(pool._idle_cache) == 0
# while the one connection is used exclusively, nothing else is served
db = pool.connection(False)
assert pool._connections == 1
assert len(pool._idle_cache) == 0
if shareable:
assert len(pool._shared_cache) == 0
with pytest.raises(TooManyConnectionsError):
pool.connection(False)
with pytest.raises(TooManyConnectionsError):
pool.connection()
assert db
del db
assert pool._connections == 0
assert len(pool._idle_cache) == 1
# when it is used as a shared connection, it can serve any number
# of shareable requests, but still no dedicated one
cache = [pool.connection()]
assert pool._connections == 1
assert len(pool._idle_cache) == 0
if shareable:
assert len(pool._shared_cache) == 1
cache.append(pool.connection())
assert pool._connections == 1
assert len(pool._shared_cache) == 1
assert pool._shared_cache[0].shared == 2
else:
with pytest.raises(TooManyConnectionsError):
pool.connection()
with pytest.raises(TooManyConnectionsError):
pool.connection(False)
if shareable:
cache.append(pool.connection(True))
assert pool._connections == 1
assert len(pool._shared_cache) == 1
assert pool._shared_cache[0].shared == 3
else:
with pytest.raises(TooManyConnectionsError):
pool.connection(True)
del cache
assert pool._connections == 0
assert len(pool._idle_cache) == 1
if shareable:
assert len(pool._shared_cache) == 0
# afterwards the connection can be used exclusively again
db = pool.connection(False)
assert pool._connections == 1
assert len(pool._idle_cache) == 0
assert db
del db
assert pool._connections == 0
assert len(pool._idle_cache) == 1
@pytest.mark.parametrize("threadsafety", [1, 2])
def test_maxconnections_raised_to_maxcached(dbapi, threadsafety):
"""Check that maxconnections is raised to the value of maxcached."""
dbapi.threadsafety = threadsafety
shareable = threadsafety > 1
pool = PooledDB(dbapi, 1, 2, 2, 1)
assert pool._maxconnections == 2
assert pool._connections == 0
assert len(pool._idle_cache) == 1
cache = [pool.connection(False)]
assert pool._connections == 1
assert len(pool._idle_cache) == 0
cache.append(pool.connection(False))
assert pool._connections == 2
assert len(pool._idle_cache) == 0
if shareable:
assert len(pool._shared_cache) == 0
with pytest.raises(TooManyConnectionsError):
pool.connection(False)
with pytest.raises(TooManyConnectionsError):
pool.connection()
@pytest.mark.parametrize("threadsafety", [1, 2])
def test_maxconnections_raised_to_mincached(dbapi, threadsafety):
"""Check that maxconnections is raised to the value of mincached."""
dbapi.threadsafety = threadsafety
pool = PooledDB(dbapi, 4, 3, 2, 1, False)
assert pool._maxconnections == 4
assert pool._connections == 0
assert len(pool._idle_cache) == 4
cache = []
for _i in range(4):
cache.append(pool.connection(False))
assert pool._connections == 4
assert len(pool._idle_cache) == 0
with pytest.raises(TooManyConnectionsError):
pool.connection(False)
with pytest.raises(TooManyConnectionsError):
pool.connection()
@pytest.mark.parametrize("threadsafety", [1, 2])
def test_maxconnections_above_maxshared(dbapi, threadsafety):
"""Check that shared connections leave room for dedicated ones."""
dbapi.threadsafety = threadsafety
shareable = threadsafety > 1
pool = PooledDB(dbapi, 1, 2, 3, 4, False)
assert pool._maxconnections == 4
assert pool._connections == 0
assert len(pool._idle_cache) == 1
# four shareable requests only need maxshared=3 connections
cache = []
for _i in range(4):
cache.append(pool.connection())
assert len(pool._idle_cache) == 0
if shareable:
assert pool._connections == 3
assert len(pool._shared_cache) == 3
cache.append(pool.connection())
assert pool._connections == 3
# so the fourth connection is still available as a dedicated one
cache.append(pool.connection(False))
assert pool._connections == 4
else:
assert pool._connections == 4
with pytest.raises(TooManyConnectionsError):
pool.connection()
with pytest.raises(TooManyConnectionsError):
pool.connection(False)
@pytest.mark.parametrize("threadsafety", [1, 2])
def test_maxconnections_equal_to_maxshared(dbapi, threadsafety):
"""Check that all connections may be shared when maxshared allows it."""
dbapi.threadsafety = threadsafety
shareable = threadsafety > 1
pool = PooledDB(dbapi, 0, 0, 3, 3, False)
assert pool._maxconnections == 3
assert pool._connections == 0
# used exclusively, the three connections are exhausted right away
cache = []
for _i in range(3):
cache.append(pool.connection(False))
assert pool._connections == 3
with pytest.raises(TooManyConnectionsError):
pool.connection(False)
with pytest.raises(TooManyConnectionsError):
pool.connection(True)
# used as shared connections, they can serve any number of requests
cache = []
assert pool._connections == 0
for _i in range(3):
cache.append(pool.connection())
assert pool._connections == 3
if shareable:
for _i in range(3):
cache.append(pool.connection())
assert pool._connections == 3
else:
with pytest.raises(TooManyConnectionsError):
pool.connection()
with pytest.raises(TooManyConnectionsError):
pool.connection(False)
@pytest.mark.parametrize("threadsafety", [1, 2])
@pytest.mark.parametrize("maxconnections", [0, None])