Expected behaviour
Redis documentation for the SELECT command says that
New connections always use the database 0
So subsequent SELECT commands on different connections should not change the database number for other connections, even if the database 0 was not explicitly selected.
And if the database for connection was changed for any reason, Redis::getDbNum() method should return database number being used.
Actual behaviour
I have the following script which runs in PHP-FPM:
<?php
$redis0 = new Redis();
$redis0->pconnect('redis', 6379, 0.0, 'redis0');
# No explicit select 0 here
$redis1 = new Redis();
$redis1->pconnect('redis', 6379, 0.0, 'redis1');
$redis1->select(1);
$redis2 = new Redis();
$redis2->pconnect('redis', 6379, 0.0, 'redis2');
$redis2->select(2);
echo $redis0->getDbNum();
$redis0->set('REDIS_0', '0');
echo $redis1->getDbNum();
$redis1->set('REDIS_1', '1');
echo $redis2->getDbNum();
$redis2->set('REDIS_2', '2');On the first and second requests the keys appear in correct databases (MONITOR output from redis-cli):
# Request 1
1611942079.015152 [0 172.18.0.9:45512] "SELECT" "1"
1611942079.016807 [0 172.18.0.9:45514] "SELECT" "2"
1611942079.017168 [0 172.18.0.9:45510] "SET" "REDIS_0" "0"
1611942079.017464 [1 172.18.0.9:45512] "SET" "REDIS_1" "1"
1611942079.017689 [2 172.18.0.9:45514] "SET" "REDIS_2" "2"
1611942219.691163 [2 172.18.0.1:47622] "flushall" # flushall from redis-cli
# Request 1
1611942223.955243 [0 172.18.0.9:45592] "SELECT" "1"
1611942223.955885 [0 172.18.0.9:45594] "SELECT" "2"
1611942223.956078 [0 172.18.0.9:45590] "SET" "REDIS_0" "0"
1611942223.956166 [1 172.18.0.9:45592] "SET" "REDIS_1" "1"
1611942223.956259 [2 172.18.0.9:45594] "SET" "REDIS_2" "2"
Checking the keys in redis-cli:
127.0.0.1:63799> keys *
1) "REDIS_0"
127.0.0.1:63799> select 1
OK
127.0.0.1:63799[1]> keys *
1) "REDIS_1"
127.0.0.1:63799[1]> select 2
OK
127.0.0.1:63799[2]> keys *
1) "REDIS_2"
However, on the third request (without flushall between requests) the "REDIS_0" key appears in the database 2:
1611942329.811933 [2 172.18.0.9:45514] "ECHO" "phpredis:601449b9c6073:1867ae6f"
1611942329.812692 [1 172.18.0.9:45512] "ECHO" "phpredis:601449b9c6586:3eac0768"
1611942329.813386 [1 172.18.0.9:45512] "SELECT" "1"
1611942329.813804 [0 172.18.0.9:45510] "ECHO" "phpredis:601449b9c6a0c:1bb3c7f6"
1611942329.814144 [0 172.18.0.9:45510] "SELECT" "2"
1611942329.814439 [2 172.18.0.9:45514] "SET" "REDIS_0" "0"
1611942329.814647 [1 172.18.0.9:45512] "SET" "REDIS_1" "1"
1611942329.814945 [2 172.18.0.9:45510] "SET" "REDIS_2" "2"
Checking the keys:
127.0.0.1:63799> keys *
1) "REDIS_0"
127.0.0.1:63799> select 1
OK
127.0.0.1:63799[1]> keys *
1) "REDIS_1"
127.0.0.1:63799[1]> select 2
OK
127.0.0.1:63799[2]> keys *
1) "REDIS_2"
2) "REDIS_0"
Meanwhile, during all the requests $redisN->getDbNum(); outputs correct database numbers: 0 1 2.
I'm seeing this behaviour on
- OS: Linux 5.10.9-201.fc33.x86_64 x86_64 (redis docker image)
- PHP: 7.4.13
- Redis: 6.0.8
- phpredis: 5.3.2
I've checked
Expected behaviour
Redis documentation for the SELECT command says that
So subsequent SELECT commands on different connections should not change the database number for other connections, even if the database 0 was not explicitly selected.
And if the database for connection was changed for any reason,
Redis::getDbNum()method should return database number being used.Actual behaviour
I have the following script which runs in PHP-FPM:
On the first and second requests the keys appear in correct databases (MONITOR output from redis-cli):
Checking the keys in redis-cli:
However, on the third request (without flushall between requests) the "REDIS_0" key appears in the database 2:
Checking the keys:
Meanwhile, during all the requests
$redisN->getDbNum();outputs correct database numbers:0 1 2.I'm seeing this behaviour on
I've checked
developbranch - not sure how do I check that