Re: weird replication problem with master.info being created empty
You need to shutdown mysql, delete the master.info and relay-log.info files and then start mysql again. The reason for this is because if the info files are present then mysql uses them as is and only recreates them from my.ini or my.cnf if absent. This should get your replication going again. regards Jurgen Have a problem, running a master/slave setup which worked until tonight and mysteriously broke with no changes to the setup at all. My server starts up fine, but the master.info and relay-log.info that are created are 0 bytes and empty. In the logfile, I get this: 040128 23:00:29 Error reading slave log configuration 040128 23:00:29 Failed to initialize the master info structure and when I run slave start I get this: ERROR 1201: Could not initialize master info structure, check permisions on master.info The blank files in question have okay permissions (mysql:mysql) as does the directory they're in, and they ARE getting written to, just nothing is being written. The my.cnf file also has appropriate permissions and is readable by mysql (so it's not a case of the server not knowing what to write in those files). Moreover, nothing has changed on the server config at all. I've tried resetting the master and slave but it doesn't help. I was running version 4.0.12-0 but just upgraded to 4.0.17-0 which hasn't helped at all, and the only thing I can find in the archives are similar problems with the same error number that either turn out to be legit permissions errors (which isn't the case here), and this: http://lists.mysql.com/bugs/15135 which I don't really follow as far as what the final solution was. __ http://www.webmail.co.za/dialup Webmail ISP - Cool Connection, Cool Price -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe:http://lists.mysql.com/[EMAIL PROTECTED]
Re: weird replication problem with master.info being created empty
Maybe you should check if the ip address resolved for the master's url is correct ? Also try using CHANGE MASTER TO MASTER_HOST='master host name', MASTER_USER='replication user name', MASTER_PASSWORD='replication password'; and then START SLAVE; and see what happens. regards Jurgen Tried that, but no luck, they get recreated, but they still have 0 bytes in them. This is really driving me crazy because although it's come up before on lists, noone has ever really had an answer for it that makes sense. The url I mentioned earlier does say something about the hostname of the server changing, but that isn't the case here, the hostname is the same as always (should have added that in the first place). You need to shutdown mysql, delete the master.info and relay-log.info files and then start mysql again. The reason for this is because if the info files are present then mysql uses them as is and only recreates them from my.ini or my.cnf if absent. This should get your replication going again. regards Jurgen Have a problem, running a master/slave setup which worked until tonight and mysteriously broke with no changes to the setup at all. My server starts up fine, but the master.info and relay-log.info that are created are 0 bytes and empty. In the logfile, I get this: 040128 23:00:29 Error reading slave log configuration 040128 23:00:29 Failed to initialize the master info structure and when I run slave start I get this: ERROR 1201: Could not initialize master info structure, check permisions on master.info The blank files in question have okay permissions (mysql:mysql) as does the directory they're in, and they ARE getting written to, just nothing is being written. The my.cnf file also has appropriate permissions and is readable by mysql (so it's not a case of the server not knowing what to write in those files). Moreover, nothing has changed on the server config at all. I've tried resetting the master and slave but it doesn't help. I was running version 4.0.12-0 but just upgraded to 4.0.17-0 which hasn't helped at all, and the only thing I can find in the archives are similar problems with the same error number that either turn out to be legit permissions errors (which isn't the case here), and this: http://lists.mysql.com/bugs/15135 which I don't really follow as far as what the final solution was. __ http://www.webmail.co.za/dialup Webmail ISP - Cool Connection, Cool Price -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe:http://lists.mysql.com/[EMAIL PROTECTED]
Group By Problem
Say I have the following table (TBL): KEY GRP VAL 1 A 2 2 A 3 3 A 1 4 B 2 5 B 1 6 B 3 select KEY, max(VAL) from TBL group by GRP gives: KEY max(VAL) 1 3 4 3 the desired result though is: KEY max(VAL) 2 3 6 3 any ideas on how to achieve this ? Apparently this query is invalid in other RDBMs (like Oracle) which don't allow it. The rule is that one should not have columns in your select that are not in the group by section, except for the grouping functions. MySQL though does allow it, but results can be strange as above. I realise that some selects don't make sense eg: select KEY, max(VAL), min(VAL) from TBL group by GRP (which KEY should be returned ?) I suppose one possibilty for solving my problem would be: 1. select GRP, max(VAL) from TBL group by GRP 2. for each row in 1.: select KEY from TBL where GRP=? and VAL=? Any other ideas or comments ? regards Jurgen __ http://www.webmail.co.za/dialup Webmail ISP - Cool Connection, Cool Price -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe:http://lists.mysql.com/[EMAIL PROTECTED]
