1. Reference URL: https://blog.csdn.net/zhanghan18333611647/article/details/81434786 . This is implemented via a program (Python version 2.x). Create a new file named migrate.py.
#!/usr/bin/env python
# -*- coding:utf-8 -*-
# 把redis里面一个数据库的东西，迁移到另外一个数据库里面
# 建立两个redis连接
# 获取到所有的key .keys()
# 判断key的类型 string\hash\list\set
import redis
#redis_from源数据，redis_to目标数据 redis_from——>redis_to
redis_from = redis.StrictRedis(host='ip',port=6379,password='',db=10)
redis_to = redis.StrictRedis(host='ip',port=6379,password='',db=0)
if __name__ == '__main__':
cnt = 0
scnt = 0
lcnt = 0
setcnt = 0
hcnt = 0
for k in redis_from.keys():
# 循环keys里面每一个key
data_type = redis_from.type(k)
# 判断key的类型 string\hash\list\set
if data_type == 'string':
v = redis_from.get(k)
t = redis_from.ttl(k)
redis_to.set(k, v)
if int(t) > 0:
redis_to.expire(k,t)
scnt = scnt + 1
elif data_type == 'list':
values = redis_from.lrange(k, 0, -1)
t = redis_from.ttl(k)
redis_to.lpush(k, values)
if int(t) > 0:
redis_to.expire(k,t)
lcnt = lcnt + 1
elif data_type == 'set':
values = redis_from.smembers(k)
t = redis_from.ttl(k)
redis_to.sadd(k, values)
if int(t) > 0:
redis_to.expire(k,t)
setcnt = setcnt + 1
elif data_type == 'hash':
hcnt = hcnt + 1
keys = redis_from.hkeys(k)
for key in keys:
value = redis_from.hget(k, key)
t = redis_from.ttl(k)
redis_to.hset(k, key, value)
if int(t) > 0:
redis_to.expire(k,t)
else:
print 'not known type'
print data_type
file_object = open('/data/thefile.txt','a+')
file_object.write(data_type)
file_object.write('\n')
file_object.close( )
cnt = cnt + 1
print 'total', cnt
print 'string', scnt
print 'list', lcnt
print 'set', setcnt
print 'hash', hcnt
2. On the self-hosted Redis machine, connect to the self-hosted Redis and the Tencent Cloud built-in Redis respectively. Database 0 of the Tencent Cloud built-in Redis is empty. I plan to use this database as the migration target. See Figure 1.
3. Check the Python version, which is Python 2.7.5. The version meets the requirements. See Figure 2.
[root@iz2zeeh3rrqalw11oajd6zz ~]# python
Python 2.7.5 (default, Nov 16 2020, 22:23:17)
[GCC 4.8.5 20150623 (Red Hat 4.8.5-44)] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>>
4. Connect to the self-hosted Redis and check the total number of keys in database 0: 40.
[root@iz2zeeh3rrqalw11oajd6zz ~]# redis-cli -h 127.0.0.1 -p 6379 -a 2021Chinamcloud
127.0.0.1:6379> select 0
OK
127.0.0.1:6379> dbsize
(integer) 40
127.0.0.1:6379>
5. Run python migrate.py. An import error occurs: ImportError: No module named redis. See Figure 3.
[root@iz2zeeh3rrqalw11oajd6zz ~]# python migrate.py
Traceback (most recent call last):
File "migrate.py", line 9, in
import redis
ImportError: No module named redis
[root@iz2zeeh3rrqalw11oajd6zz ~]#
6. After installing redis-py, continue running python migrate.py.
[root@iz2zeeh3rrqalw11oajd6zz ~]# python migrate.py
Traceback (most recent call last):
File "migrate.py", line 39, in
redis_to.lpush(k, values)
File "/usr/lib/python2.7/site-packages/redis/client.py", line 1961, in lpush
return self.execute_command('LPUSH', name, *values)
File "/usr/lib/python2.7/site-packages/redis/client.py", line 900, in execute_command
conn.send_command(*args)
File "/usr/lib/python2.7/site-packages/redis/connection.py", line 725, in send_command
self.send_packed_command(self.pack_command(*args),
File "/usr/lib/python2.7/site-packages/redis/connection.py", line 775, in pack_command
for arg in imap(self.encoder.encode, args):
File "/usr/lib/python2.7/site-packages/redis/connection.py", line 120, in encode
"bytes, string, int or float first." % typename)
redis.exceptions.DataError: Invalid input of type: 'list'. Convert to a bytes, string, int or float first.
[root@iz2zeeh3rrqalw11oajd6zz ~]#
7. Check the Redis versions respectively. The self-hosted Redis version is 3.2.12. The Tencent Cloud built-in Redis version is 2.8.23. The versions are inconsistent. See Figure 4 and Figure 5.
[root@iz2zeeh3rrqalw11oajd6zz ~]# redis-cli -h 127.0.0.1 -p 6379 -a 2021Chinamcloud
127.0.0.1:6379> select 0
OK
127.0.0.1:6379> info
# Server
redis_version:3.2.12
redis_git_sha1:00000000
redis_git_dirty:0
redis_build_id:7897e7d0e13773f
redis_mode:standalone
os:Linux 3.10.0-1160.11.1.el7.x86_64 x86_64
RDM Redis Console
Connecting...
Connected.
Tencent Cloud (Company Development Environment):0>info
"# Server
redis_version:2.8.23
run_id:0a99b4d4dac9744a76075aa77a978a2dfcdf1ba6
uptime_in_seconds:74995115
uptime_in_days:867
hz:10
lru_clock:8808554
8. Check the installed redis version in Python. Create a new file named python_redis.py, and observe that the version is 3.5.3. See Figure 6.
import redis
print redis.VERSION
9. Execute the command: pip install redis==2.10.6. Roll back the version to 2.10.6. See Figure 7.
10. After rolling back the version to 2.10.6, continue running python migrate.py. The data migration is successful. The reason why the total number of keys migrated in database 0 is 53 is that the data in the self-hosted Redis was changing. See Figure 8.
[root@iz2zeeh3rrqalw11oajd6zz ~]# python python_redis.py
(2, 10, 6)
[root@iz2zeeh3rrqalw11oajd6zz ~]# python migrate.py
total 53
string 25
list 3
set 0
hash 25
11. Check the data in database 0 of the Tencent Cloud built-in Redis. The total number of keys is 53, confirming the migration was successful. When the Tencent Cloud built-in Redis is version 4.0, the migration can also succeed. See Figure 9.
