[clue] MySQL Question

[adam bultman]

On 11/30/2012 02:42 PM, Jason Friedman wrote:
>> I've inherited a complex LAMP application.
>>
>> A script runs nightly to dump the databases for a backup.  After the
>> dumps and before emailing the results, the script issues the following
>> commands on each database:
>>
>>   mysql -u <user> -p<password> -h <DB Server> -e "reset master"
>>   mysql -u <user> -p<password> -h <DB Server> -e "flush logs"
>>
>> What does "reset master" and "flush logs" do to a running database?  At
>> no time does the script stop and restart the instances, BTW.
Reset master: Removes all the binary logs.
Flush logs:  Closes and reopens all log files.

It might make more sense to reset the master after *all* DB dumps are 
complete; because you could in theory lose changes that were made 
mid-backup process.  Flush logs seems near pointless.

Like Raymond said, if replication is being used, it's a big no-no. If I 
issue that command on my master MySQL server, I made myself a lot of work.

You might spend some time 'auditing' this complex application to see if 
some of the complexity is the result of a lack of knowledge on the 
previous admin's part.  I've inherited a lot of those, and most 
certainly left some of those types of things behind, personally.