I already read a few threads here and I also went through the MySQL Replication Documentation (incl. Cluster Replication), but I think it’s not what I really want and propably too complicated, too.
I got a local and a remote DB that might get both accessed/manipulated by 2 different persons at the same time. What I’d like to do is to sync them as soon as possible (means instantly or as soon the local machine goes online). Both DB’s only get manipulated from my own PHP Scripts.
My approach is the following:
If local machine is online:
- Let my PHP Script on the loal machine always send the SQL Query to the remote DB too
- Let my PHP Script on the remote machine always store its queries and…
- …let the local machine ask the remote DB every x minutes for new queries and apply them locally.
If local machine is offline:
Do step 2. also for both machines and send the stored queries to the remote DB as soon as
local machine goes online again. Also pull the queries from the remote machine for sure.
My questions are:
- Did I just misunderstand Replication or am I right that my way would be easier in my case? Or is there any other good solution for what I’m trying to accomplish?
- Any idea how I could check whether my local machine is online/offline? I guess I’d have to use JavaScript, but I don’t know how. The browser/my script would always be running on the local machine.
What you’re describing is master-master or multi-master replication. There are plenty of tutorials on how to set this up across the web. Definitely do your research before putting a solution like this into production as replication in MySQL isn’t exactly elegant — you need to know how to recover if (when?) something goes wrong.