ALTER TABLE using reserved word (1 reply)
I had mental slippage one day and added a column called "status" after an existing column... I also added another column after my newly created "status" column... The alters looked like this: ALTER...
View ArticleMysql mysql hangs up 1-2 times per day (no replies)
MySQL after some period of time just hangs up... I'm thinking that it's table lock or dead lock, but cant prove that or find how to fix situation... OS : Debian 7.7 Mysql version : 5.6.20-68.0 Table...
View ArticleRegarding stack trace of different threads for a mysqld process (no replies)
I would like to know is there any tool which can provide me the stack trace of all the threads for a mysqld process. For example, we are using jstack tool for displaying the stack traces of java...
View ArticleMysql crash with glibc errors (1 reply)
Hello, Mysql server-5.6.16 got crashed , i dont know the particular scenario so i am not able to regenrate that crash. I do have SAN storage connected with Mysql server. Please check following error...
View Articlewhy UPDATE requires share lock(S) for table joined (3 replies)
for example update t inner join lktest on lktest.c3=t.x set t.y=t.y where lktest.c3=2; in this case , mysql always places share lock on the rows(c3=2) of lktest table no matter what transaction level...
View ArticleFunction and indexes (1 reply)
Hi, I'd like to know if there are functions which, when used in WHERE conditions on indexed columns, these conditions continue to use indexes. An example: Select * From MyTable Where MyColumn Like...
View ArticleWhat's the format of the redo log record? (no replies)
Hi all, I've been reading the source code and trying to figure what exactly the format of the redo log record is. I found some articles talking about this, but they are different from what I find in...
View ArticleData loss after hardware fault (no replies)
I'm experiencing some troubles with data loss after power or hardware fault of a innodb/mysql installation in desktop PC computer. Db is used by a web application used every days. These are the facts...
View ArticleHow to measure each MySQL query CPU utilization. (1 reply)
I am running MySQL 5.6 on Linux platform. I want to put some load(like Insert/Read/Delete query ) on MySQL server and want to measure CPU consumption (even in millisecond and microsecond) at run time...
View Articledoes NO_ZERO_ON_DATE working bad in 5.1? (no replies)
Hi all, I'd like to prevent that some SQL generate wrong date, and I tried to use NO_ZERO_ON_DATE, but it seems that it doesn't run well: select @@session.sql_mode ; Select cast(data as datetime) As...
View ArticleWhen does innodb buffer pool charge for memory? (no replies)
Hi, I have 16G Ram on System. I configure for innodb_buffer_pool = 6G. when I start the mysql server. How many memory does system use for innodb_buffer_pool? all of 6G ? or some low memory?
View Articlehow to tune for innodb_io_capacity? (no replies)
Hi, I have a test for insert and read performance in mysql. I'm expecting mysql server to accommodate about 1.3 ~ 2 GB/Sec. Please tell me how to configure it. Thanks
View ArticleInnoDB byte limit encountered with a column for emails (1 reply)
I am trying to switch an email column set to VARCHAR(255) from the charset/collation of latin1_swedish_ci to utf8mb4_unicode_ci. The column also is set to unique and has a unique index associated with...
View ArticleSelects grinding to a halt with 16 inserts/min (no replies)
I've just switched a table with 2.5 million rows to InnoDB to avoid table locking but I'm still seeing a significant slow down of select queries when the table is being updated. When the table is not...
View Articleshow processlist state statistics make cpu increase cpu usage (no replies)
Hi, show processlist state statistics make cpu increase cpu usage. How can I reduce the cpu usage in this status? what variables can I change?
View Articlemissing InnoDB (partitioned) tables(s) ? (no replies)
Has anyone experienced missing InnoDB (partitioned) tables(s) after a disk has been full? I know, it may sound weird… Basically I’ve been testing a little bit, “no space left on device” occurred (my...
View ArticleCan't edit the tables in innoDB (3 replies)
Hi guys, I got a problem with my WordPress-sites running on my VPS. Some of the tables are in innoDB and some in MyISAM. I can't edit the tables that are in innoDB. In my my.cnf-file I got...
View Articlewhy delete will block by select? (2 replies)
hi ,all: i am very confused about this deadlock,here is the detail info,why the delete will be blocked by select ? *** (1) TRANSACTION: TRANSACTION 657EBD98, ACTIVE 0 sec fetching rows mysql tables in...
View ArticleInnoDB use TABLE LOCK ? (1 reply)
Hi As I know that innodb just use row level lock. is it right? when it alter table definition. does innodb use table lock ? or not use ? when altering index ? adding index ? modifing colums ? does it...
View ArticleInnoDB buffer pool setting of large Innodb database (2 replies)
Hi Friends, I have a dedicated Mysql server with 16 GB of RAM and my database size (data and Index) is about 42 GB. I have already set InnoDB Buffer Pool size 12 GB as per mysql recommandation. My all...
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