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Jun
9
comment Dynamically change schema to accommodate custom fields!
@ThaDafinser, thank you!
Feb
24
comment How are auto_increment keys handled in INSERT (SELECT * FROM…)
@Pacerier, the pivot/transpose functions I have seen do not make the column headers into a column. So your made-up syntax does not work. I don't know why you're trying to do acrobatics to avoid using select *. This problem has a straightforward solution.
Feb
24
comment How are auto_increment keys handled in INSERT (SELECT * FROM…)
@Pacerier, if I understand correctly, you're asking if select * can mean select * except for the first column. The answer is no. select * always requests all the columns from that table. If you want a subset, you must spell out the columns you want.
Nov
25
comment Increase performance WITHOUT adding indexes
@RolandoMySQLDBA, have you gotten improvement from putting tmpdir on a tmpfs? I have tried it and found little to no improvement. The overhead of creating temp tables seems to be the bottleneck. The savings by using tmpfs isn't enough to fix performance issues. I suspect temp tables on disk use the filesystem cache and end up living in system memory anyway.
Nov
25
comment Increase performance WITHOUT adding indexes
@TobiasBaumeister, tmp tables on "disk" (even if it's a RAM disk or tmpfs) uses the MyISAM storage engine by default. You can also put a limit on the size of the RAM disk. Whereas tmp tables in memory use the MEMORY (aka HEAP) storage engine, and can use up to tmp_table_size memory per thread. Also, MEMORY storage engine does not support TEXT/BLOB columns.
Oct
29
comment How can i make dump of big mysql table?
"Connection timed out" or "No route to host" when you try to connect usually indicates that you cannot reach the server from the host you're running the mysqldump client on. Sounds like you have no access to the server at all, possibly because of a firewall. You should talk to the network administrator to find out if you can get a VPN connection or access to another client host on the same network.
Oct
10
comment Percona MySQL 5.5 Unique key is duplicated
@PrakashK, here's a link: dev.mysql.com/doc/refman/5.6/en/binary-log.html
Oct
2
comment Upgrading to new cPanel Server with mySQL on SSD — What should I change in my.cnf?
@ceejayoz, we at Percona frequently see scaling problems that are fixed by disabling the query cache. I advise to disable it unless you see a very favorable ratio of QC hits/misses, perhaps 10:1 or more.
Sep
26
comment Using an index for both asc and desc on a string column
@ypercube, yeah, you're right, I think I created the collation naively by just reversing the order of all the bytes. It turns out that designing collations is more complex than can be done in a few minutes in a StackOverflow post! :-) Anyway, this answer at least serves as a demo of how to do it.
Sep
26
comment Using an index for both asc and desc on a string column
@ypercube, see example of CHAR above.
Sep
25
comment Using an index for both asc and desc on a string column
It's a pretty odd case.
Sep
25
comment Using an index for both asc and desc on a string column
@Cratylus, I just copied the block of codes from the latin1_general_ci collation in the same file, and reversed the order.
Sep
25
comment Speed Up Index Creation in MySQL
I guess I assume everyone using MySQL is using a Linux server. Because for the most part, they are. Running a Windows server on a VM seems to me like fighting a boxing match with both hands tied behind your back.
Sep
25
comment Speed Up Index Creation in MySQL
See msdn.microsoft.com/library/dn197896.aspx, it confirms that you only get 300 IOPS per disk in Azure. That's really disappointing.
Sep
25
comment Speed Up Index Creation in MySQL
Okay then go with the tmpfs solution. Based on this and your other question, it sounds like your VM disks are really slow.
Sep
12
comment Amazon: How to change database name in Amazon RDS MySQL?
Aha, I tried it, and that doesn't work if you have triggers. I get an error: ERROR 1435 (HY000): Trigger in wrong schema
Sep
12
comment Amazon: How to change database name in Amazon RDS MySQL?
Why not just RENAME TABLE tablename TO db2.tablename; for each table? Then there shouldn't be any shipping of data back and forth.
Sep
4
comment MySQL does not start - Ubuntu 14.04 LTS after migration to new disk
At this point I'd try using sudo -u mysql -g mysql and see if you can read and write files under the datadir. It could still be permission problems in the ancestor directories, or it could be AppArmor interfering and giving misleading error messages. Try disabling AppArmor temporarily and see if that makes the errors go away.
Sep
4
comment Calculating RAM requirements for an in-memory database
Check the total resident memory used by all processes by summing the RSS column from ps. You can also use free to check RAM in use. Also don't forget to leave some spare RAM for filesystem buffers.
Sep
1
comment How to generate auto increment values for my duplicate column in my sql?
You just cross-posted this on StackOverflow. Please post to one site.