用Python脚本迁移MongoDB数据到金仓-kingbase数据库

1、首先需要明确MongoDB与kingbase的对应关系，collection相当于table，filed相当于字段，根据这个对应关系创建表；

此次迁移的MongoDB里的数据字段是：_id（自动生成的objectid），image（转成二进制存储的文档）

所以在金仓里创建表 create table admin(id varchar,image bytea);

2、安装Python环境，由于是内网环境，没有yum源，需要从能连接互联网的环境下载好相应的安装包

Python：3.9.0版本

用到以下这些包

import pymongo
import ksycopg2
import concurrent.futures
from ksycopg2 import pool
import logging
from urllib.parse import quote_plus

------------------------------------------------------------------------------------

pip download pymongo -d pymongo_packages --下载pymongo库

pip3 install --no-index --find-links=. pymongo --安装pymongo库

金仓的Python驱动可以到金仓官网下载，需要找和Python对应的版本

以下是Python脚本内容：

import pymongo
import psycopg2
import concurrent.futures
from psycopg2 import pool
import logging
from urllib.parse import quote_plus
import os

# 初始化日志记录
logging.basicConfig(level=logging.INFO, format='%(asctime)s - %(levelname)s - %(message)s', datefmt='%Y-%m-%d %H:%M:%S')

# MongoDB设置
username='admin'
password='SCJGscjg@123'
host='10.253.228.41'
port='27017'
encoded_username = quote_plus(username)
encoded_password = quote_plus(password)
uri = f"mongodb://{encoded_username}:{encoded_password}@{host}:{port}/"
mongo_client = pymongo.MongoClient(uri)
mongo_db = mongo_client['admin']
mongo_collection = mongo_db['admin']

# 连接池设置
kb_pool = psycopg2.pool.ThreadedConnectionPool(
    minconn=1,
    maxconn=20,
    host="10.253.228.110",
    database="mongo",
    user="system",
    password="1",
    port="54322"
)

# 偏移量存储文件
OFFSET_FILE = 'offset.txt'

def read_offset():
    if os.path.exists(OFFSET_FILE):
        with open(OFFSET_FILE, 'r') as f:
            return int(f.read().strip())
    return 0

def write_offset(offset):
    with open(OFFSET_FILE, 'w') as f:
        f.write(str(offset))

def batch_insert(mongo_data):
    kb_conn = None
    try:
        kb_conn = kb_pool.getconn()
        with kb_conn.cursor() as kb_cursor:
            for data in mongo_data:
                id_value = data['_id']
                image_data = data['image']
                insert_query = "INSERT INTO dzzzwj(id, image) VALUES (%s, %s)"
                kb_cursor.execute(insert_query, (id_value, image_data))
            kb_conn.commit()
        return True
    except Exception as e:
        logging.error(f"批量插入错误: {e}")
        return False
    finally:
        if kb_conn:
            kb_pool.putconn(kb_conn)

def main():
    batch_size = 80
    offset = read_offset()
    executor = concurrent.futures.ThreadPoolExecutor(max_workers=8)
    
    try:
        while True:
            mongo_data = list(mongo_collection.find().skip(offset).limit(batch_size))
            if not mongo_data:
                break

            future = executor.submit(batch_insert, mongo_data)
            future.add_done_callback(lambda f, offset=offset: (
                logging.info(f"Batch completed with offset {offset}") if f.result() else logging.error(f"Batch failed with offset {offset}"),
                write_offset(offset + batch_size) if f.result() else None
            ))
            offset += batch_size if future.result() else 0
    except Exception as e:
        logging.error(f"主循环错误: {e}")
    finally:
        executor.shutdown(wait=True)
        mongo_client.close()
        kb_pool.closeall()
        logging.info("资源已清理完毕。")

if __name__ == "__main__":
    main()

这段代码思路：

（1）连接MongoDB和kingbase数据；

（2）因为MongoDB数据量比较大，并且需要断点续传，索引用了分页和排序；

（3）数据成功插入金仓数据库后，增加偏移量，并且将当前偏移量记录在offset.txt里面，以便脚本停了，可以再重启接着迁数据；

因为二进制数据从MongoDB和金仓数据查询出来的内容看着不一样，所以下面的代码是计算两边数据md5值对比的简单代码

import pymongo
import ksycopg2
import base64
import hashlib

def compute_hash(data):
    return hashlib.md5(data).hexdigest()

mongo_client = pymongo.MongoClient('mongodb://127.0.0.1:27017/')
mongo_db = mongo_client['admin']
mongo_collection = mongo_db['mongodb']

database = "test"
user = "system"
password = "1"
host = "127.0.0.1"
port = "54322"

conn = ksycopg2.connect(database=database, user=user, password=password, host=host, port=port)

cursor = conn.cursor()


mongo_data = mongo_collection.find()
print(mongo_data)    

    # 插入到 kingbase
for data in mongo_data:
   id_value = data['_id']
   image_data = data['image']

   #image_data = base64.b64encode(base64_data).decode('utf-8')

   image_data_byte = image_data 
   if isinstance(image_data, bytes):
       mongo_hash = compute_hash(image_data_byte)
       print(mongo_hash)

   #image_data = base64.b64encode(base64_data).decode('utf-8')
   if id_value and image_data:
      insert_query = "INSERT INTO zzwj(_id, image) VALUES (%s, %s)"
      cursor.execute(insert_query, (id_value, image_data))

    # 提交事务
conn.commit()

cursor.execute("select _id, image from zzwj")
rows = cursor.fetchall()

for row in rows:
    _id = row[0]
    image_byte = row[1]
    
    pg_hash = compute_hash(image_byte)
    print(pg_hash)


# 关闭连接
cursor.close()
conn.close()
mongo_client.close()