How to install and use the database connection pool DBUtils

Preface

DBUtils is a Python library for managing database connection pools. It provides management of connection pools to avoid re-establishing connections every time a database operation is performed. With DBUtils, you can manage database connections more efficiently, especially in high concurrency, which can effectively reduce the overhead of creating and destroying connections. DBUtils supports a variety of database drivers, including MySQL, PostgreSQL, SQLite, etc.

Install DBUtils

First, use pip to install DBUtils:

pip install dbutils

Connect to the pool using DBUtils

Here is a simple example of how to manage MySQL database connection pools using DBUtils.

import MySQLdb
from dbutils.pooled_db import PooledDB

# Create a database connection poolpool = PooledDB(
    creator=MySQLdb,    # Database driver, use MySQLdb to connect to MySQL database    maxconnections=10,   # Maximum number of connections allowed in the connection pool    mincached=2,         # Number of free connections created during initialization    maxcached=5,         # Maximum number of idle connections in the connection pool    maxshared=3,         # Maximum number of shared connections in the connection pool    blocking=True,       # Whether to block and wait if there is no connection available    host='localhost',    # Database host address    user='your_username',# Database username    passwd='your_password', # Database Password    db='your_database',  # Database name    port=3306            # Database Port)

# Get a connection from the connection poolconn = ()

# Get cursorcursor = ()

# Perform query operationstry:
    ("SELECT * FROM your_table")
    result = ()
    for row in result:
        print(row)
finally:
    ()  # Close cursor    ()    # Return the connection to the connection pool

Code explanation

1. Create a connection pool: PooledDB is used to create a database connection pool. Its parameters are as follows:

creator: Specifies the driver library used to connect to the database, usually a database driver like MySQLdb or pymysql.
maxconnections: The maximum number of connections in the connection pool.
mincached: The number of free connections created when the connection pool is initialized.
maxcached: The maximum number of idle connections in the connection pool.
maxshared: The maximum number of shared connections allowed.
blocking: Whether to block if there is no connection available to the connection pool. True means blocking, False means no blocking.

2. Get the connection: Use () to obtain a database connection from the connection pool.

3. Operate the database: Use the connection to create a cursor (), and then execute SQL statements to query or modify the database.

4. Close cursor and connection: Use () to close the cursor and return the connection to the connection pool with () instead of actually closing the connection.

Configuration options:

maxconnections: The maximum number of connections allowed in the connection pool. If the connection pool is full, it will block until a connection is idle (if blocking=True).
mincached: The minimum number of connections in the connection pool. This number of connections is created when initialized. If there are enough connections in the pool, new connection requests will use the idle connection directly.
maxcached: The number of free connections in the connection pool. If this number exceeds, the idle connection will be destroyed.
maxshared: The maximum number of connections that can be shared in the connection pool. When the maximum number of shares is reached, other requests will queue for an idle connection.
blocking: If True, when there is no connection available to the connection pool, the program will block until a connection is available. If it is False, an exception will be thrown.

Use DBUtils for database operations

Perform an insert operation

conn = ()
cursor = ()

try:
    ("INSERT INTO your_table (col1, col2) VALUES (%s, %s)", ('value1', 'value2'))
    ()  # Submit transactionfinally:
    ()
    ()

Perform update operations

conn = ()
cursor = ()

try:
    ("UPDATE your_table SET col1 = %s WHERE col2 = %s", ('new_value', 'value2'))
    ()  # Submit transactionfinally:
    ()
    ()

Exception handling

When using a connection pool, you can use exception handling to catch errors in database operations:

try:
    conn = ()
    cursor = ()
    ("SELECT * FROM your_table")
    result = ()
    for row in result:
        print(row)
except Exception as e:
    print(f"An error occurred: {e}")
finally:
    ()
    ()

advantage

Improve performance: Avoid the overhead of establishing and closing connections for every database operation.
Reduce resource consumption: Database connections are expensive resources, and the connection pool can reuse established connections, reducing the number of connections.
Automatic management: DBUtils automatically manages connection pools to help you easily handle connection acquisition and return.

Summarize

DBUtils is a very convenient library that can help you efficiently manage database connection pools in Python. By reasonably configuring the size of the connection pool, the number of idle connections and the maximum number of connections, the performance and resource utilization of database operations can be effectively improved. Very useful for high concurrency crawlers, web applications and other projects.

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