Which Gateway database is in use? (MySQL replication master-master)

Document created by ajake01 Employee on Jan 5, 2016
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Hi there,

 

I have found this write-up,  I though it could be helpful ...


With respect to monitoring which Gateway database is in use: You can determine which host is the active host by checking the output of `netstat -tnap` to see where TCP connections over the designated MySQL port are connecting to.

 

For an example:

 

Output of netstat on the primary (on 192.168.1.10):

tcp    0    0    0.0.0.0:3306        0.0.0.0:*            LISTEN        - Listening on all interfaces at port 3306

tcp    0    0    192.168.1.10:3306    192.168.1.10:53540    ESTABLISHED   - Local GW connecting to a local DB. 192.168.1.10 is using 192.168.1.10 as the active DB

tcp    0    0    192.168.1.10:3306    192.168.1.20:42631    ESTABLISHED   - Remote connecting to a local DB. 192.168.1.20 is using 192.168.1.10 as the active DB

tcp    0    0    192.168.1.10:31722   192.168.1.10:3307     ESTABLISHED   - Local GW connecting to a remote DB for replication.

 

 

Output of netstat on the secondary (on 192.168.1.20):

tcp    0    0    0.0.0.0:3306        0.0.0.0:*            LISTEN        - Listening on all interfaces at port 3306

tcp    0    0    192.168.1.20:20613   192.168.1.10:3306     ESTABLISHED   - Local GW connecting to a remote DB. 192.168.1.20 is using 192.168.1.10 as the active DB

tcp    0    0    192.168.1.20:42631   192.168.1.10:3306     ESTABLISHED   - Local GW connecting to a remote DB. 192.168.1.20 is using 192.168.1.10 as the active DB

tcp    0    0    192.168.1.10:3307    192.168.1.10:16249    ESTABLISHED   - Remote GW connecting to local DB for replication.

 

 

To summarize: Look at the TCP connections for port 3306 on a Gateway appliance. A majority (if not all of them, outright) will be connected to whichever database host is considered "active" (regardless of primary or secondary status).

 

 

OR ...

 

Run below mysql query on both nodes Primary and Secondary DB

 

mysql -e 'show processlist';

 

The one that lists more connections is the one that is active.

 

 

Thanks
CA Support
Kemal Ajan

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