Innodb lock tables (1 reply)
Can somebody please explain me following scenario: User A - lock tables test_table; User B - insert into test_table values ('test'); Why does User B never run into a timeout?
View ArticleWhat is the actual difference between innodb_autoinc_lock_mode 0,1,2 (no...
I would like to understand the differences between innodb_autoinc_lock_mode options 0,1 and 2 when parallel load data infiles are given. I see in "0" option, it locks the entire table and does the...
View ArticleInternal Temporary tables (no replies)
Hello, I have a question about the internal temporary tables which are created when ever ORDER BY or GROUP BY are used. As far I understood the internal temporay tables are created initially in...
View ArticleHow do i change the password of a USER in MySql (no replies)
hi folks, I want to know how can i change the password of MySql ? I presently login as 'har' with password 'hello' say i want to change the password to root.how do i do it ? Thanks in advance.
View Articlealter multiple tables (no replies)
I need to alter several tables in one database. The following commands needs to be executed on each table: alter table tbl modify column ID bigint(20) NOT NULL; alter table tbl DROP PRIMARY KEY; alter...
View ArticleInnoDB in 5.6 ULTRA FAST? (no replies)
Hello! I already installed MySQL 5.6 in one laptop just for tests. in the same computer i have MySQL 5.5 and one table with 59 million rows, I migrated the same table to 5.6 in the same computer, so I...
View Articlehard to test select for update scenario (2 replies)
Hi, Consider a table with just one column, the primary key, a string, or possibly a second counting column with no meaning. It has 1000000s of rows. Transactions that use the rows in this table for...
View ArticleNegative numbers in InnoDB Status (no replies)
There are some negative numbers displayed in the InnoDB Engine Status output. Anybody has encountered this or know why this happens ? ---------------------- BUFFER POOL AND MEMORY...
View Articlehow to recover this innodb error ? (no replies)
The Mysql server 5.5.27 has been running more than 30 days, but the below error suddey occurs. the table files exists. how to repair or recover the problem? I restarted the Mysql server , but can't...
View ArticleSQL Error (1064): You have an error in your SQL syntax. (1 reply)
Hi I'm new to MYSQL My company has version 4.0.16 of MySQL and I installed onto My Laptop for testing the latest version, I know first problem. but please could someone help in correcting the error....
View ArticleCreate table, drop database, much slower on better server (no replies)
Problem Server A runs MySQL 5.5.19 and InnoDB. When creating a database or a table and even an issuing a select takes much longer than exact the same statements on Server B. Server B runs MySQL...
View ArticleOrder of execution (1 reply)
Hi Guys, not sure if this is the ideal forum for my problem, but I have a question on order of execution of mysql queries. In particular, if the the same query was executed twice, on a mysql server...
View Articlelarge table design / query performance (3 replies)
I need advise on how to speed up queries from a large table (MySQL 5.5 INNODB). I believe the problem is my primary key consists of strings and sorting the data is taking a long time and my queries...
View ArticleHelp Optimizing Large Query Sort (Detailed) (5 replies)
Hello, I'm hoping i can find help with this here because I've reached the end of my understanding with the problem I'm facing. I manage a db, but my experience with db administration has been limited...
View ArticleInnoDB table locking error (2 replies)
I'm seeing this error in my logs after running a query: [ERROR] Got error 147 when reading table './epi/epi_qe_meas_values' Looking up that error, it's: MySQL error code 147: Lock table is full;...
View Articlealter table foreign key syntax error (1 reply)
Hi, I have two problems when I tried to modify a column to foreign key reference, appreciate helps: 1. Change to foreign key I have two tables both have an identical column provider_id tinyint(8)...
View ArticleError doing Create Table with Auto_Increment row (1 reply)
I am attempting to create a table with an auto_increment row as the last row of a primary key. It works for a primanry key with two rows but this key has three rows. I am using MySQL 5.5.16 on a local...
View ArticleHow long would a delete take for 50 million records in MySQL with the InnoDB...
How long would a delete take for 50 million records in MySQL with the InnoDB engine? Server Config: MySQL Version 5.0.77 CentOS 5.4 Final 64 bit 16GB RAM RAID 5 Processor Model : Intel(R) Xeon(R) CPU...
View ArticleDeadlock issue when transaction tries to accuire a lock it's already holding...
I've found a very confusing deadlock situation that I need help to understand. There are two transactions going on: (2) holds a lock for the query delete from myTable where id =...
View ArticleMinimize locking on UPDATE with multiple WHERE columns (no replies)
I have a problematic query that's causing a lock timeout: UPDATE <some_table> SET row1=<some value> WHERE row1 IS NULL AND row2 > <some value> ORDER BY row2 LIMIT 100 I have two...
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