Initial Commit
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qewc
0
db/__init__.py
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0
db/__init__.py
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237
db/dbConnector.pyx
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db/dbConnector.pyx
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import queue
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import MySQLdb
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import MySQLdb.cursors
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import time
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from objects import glob
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from common.log import logUtils as log
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class worker:
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"""
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A single MySQL worker
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"""
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def __init__(self, connection, temporary=False):
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"""
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Initialize a MySQL worker
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:param connection: database connection object
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:param temporary: if True, this worker will be flagged as temporary
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"""
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self.connection = connection
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self.temporary = temporary
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log.debug("Created MySQL worker. Temporary: {}".format(self.temporary))
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def ping(self):
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"""
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Ping MySQL server using this worker.
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:return: True if connected, False if error occured.
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"""
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c = self.connection.cursor(MySQLdb.cursors.DictCursor)
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try:
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c.execute("SELECT 1+1")
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return True
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except MySQLdb.Error:
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return False
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finally:
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c.close()
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def __del__(self):
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"""
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Close connection to the server
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:return:
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"""
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self.connection.close()
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class connectionsPool:
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"""
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A MySQL workers pool
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"""
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def __init__(self, host, username, password, database, size=128):
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"""
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Initialize a MySQL connections pool
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:param host: MySQL host
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:param username: MySQL username
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:param password: MySQL password
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:param database: MySQL database name
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:param size: pool max size
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"""
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self.config = (host, username, password, database)
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self.maxSize = size
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self.pool = queue.Queue(self.maxSize)
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self.consecutiveEmptyPool = 0
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self.fillPool()
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def newWorker(self, temporary=False):
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"""
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Create a new worker.
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:param temporary: if True, flag the worker as temporary
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:return: instance of worker class
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"""
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db = MySQLdb.connect(
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*self.config,
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autocommit=True,
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charset="utf8",
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use_unicode=True
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)
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conn = worker(db, temporary)
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return conn
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def fillPool(self, newConnections=0):
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"""
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Fill the queue with workers
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:param newConnections: number of new connections. If 0, the pool will be filled entirely.
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:return:
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"""
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# If newConnections = 0, fill the whole pool
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if newConnections == 0:
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newConnections = self.maxSize
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# Fill the pool
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for _ in range(0, newConnections):
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if not self.pool.full():
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self.pool.put_nowait(self.newWorker())
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def getWorker(self, level=0):
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"""
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Get a MySQL connection worker from the pool.
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If the pool is empty, a new temporary worker is created.
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:param level: number of failed connection attempts. If > 50, return None
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:return: instance of worker class
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"""
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# Make sure we below 50 retries
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#log.info("Pool size: {}".format(self.pool.qsize()))
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glob.dog.increment(glob.DATADOG_PREFIX+".mysql_pool.queries")
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glob.dog.gauge(glob.DATADOG_PREFIX+".mysql_pool.size", self.pool.qsize())
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if level >= 50:
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log.warning("Too many failed connection attempts. No MySQL connection available.")
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return None
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try:
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if self.pool.empty():
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# The pool is empty. Spawn a new temporary worker
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log.warning("MySQL connections pool is empty. Using temporary worker.")
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worker = self.newWorker(True)
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# Increment saturation
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self.consecutiveEmptyPool += 1
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# If the pool is usually empty, expand it
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if self.consecutiveEmptyPool >= 10:
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log.warning("MySQL connections pool is empty. Filling connections pool.")
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self.fillPool()
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else:
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# The pool is not empty. Get worker from the pool
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# and reset saturation counter
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worker = self.pool.get()
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self.consecutiveEmptyPool = 0
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except MySQLdb.OperationalError:
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# Connection to server lost
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# Wait 1 second and try again
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log.warning("Can't connect to MySQL database. Retrying in 1 second...")
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glob.dog.increment(glob.DATADOG_PREFIX+".mysql_pool.failed_connections")
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time.sleep(1)
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return self.getWorker(level=level+1)
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# Return the connection
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return worker
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def putWorker(self, worker):
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"""
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Put the worker back in the pool.
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If the worker is temporary, close the connection
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and destroy the object
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:param worker: worker object
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:return:
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"""
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if worker.temporary or self.pool.full():
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# Kill the worker if it's temporary or the queue
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# is full and we can't put anything in it
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del worker
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else:
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# Put the connection in the queue if there's space
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self.pool.put_nowait(worker)
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class db:
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"""
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A MySQL helper with multiple workers
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"""
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def __init__(self, host, username, password, database, initialSize):
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"""
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Initialize a new MySQL database helper with multiple workers.
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This class is thread safe.
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:param host: MySQL host
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:param username: MySQL username
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:param password: MySQL password
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:param database: MySQL database name
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:param initialSize: initial pool size
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"""
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self.pool = connectionsPool(host, username, password, database, initialSize)
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def execute(self, query, params = ()):
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"""
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Executes a query
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:param query: query to execute. You can bind parameters with %s
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:param params: parameters list. First element replaces first %s and so on
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"""
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cursor = None
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worker = self.pool.getWorker()
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if worker is None:
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return None
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try:
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# Create cursor, execute query and commit
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cursor = worker.connection.cursor(MySQLdb.cursors.DictCursor)
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cursor.execute(query, params)
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log.debug(query)
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return cursor.lastrowid
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finally:
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# Close the cursor and release worker's lock
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if cursor is not None:
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cursor.close()
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if worker is not None:
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self.pool.putWorker(worker)
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def fetch(self, query, params = (), _all = False):
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"""
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Fetch a single value from db that matches given query
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:param query: query to execute. You can bind parameters with %s
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:param params: parameters list. First element replaces first %s and so on
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:param _all: fetch one or all values. Used internally. Use fetchAll if you want to fetch all values
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"""
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cursor = None
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worker = self.pool.getWorker()
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if worker is None:
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return None
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try:
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# Create cursor, execute the query and fetch one/all result(s)
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cursor = worker.connection.cursor(MySQLdb.cursors.DictCursor)
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cursor.execute(query, params)
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log.debug(query)
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if _all:
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return cursor.fetchall()
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else:
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return cursor.fetchone()
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finally:
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# Close the cursor and release worker's lock
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if cursor is not None:
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cursor.close()
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if worker is not None:
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self.pool.putWorker(worker)
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def fetchAll(self, query, params = ()):
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"""
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Fetch all values from db that matche given query.
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Calls self.fetch with all = True.
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:param query: query to execute. You can bind parameters with %s
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:param params: parameters list. First element replaces first %s and so on
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"""
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return self.fetch(query, params, True)
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