MySQL 5.5 brought many performance enhancements and expanded the feature set of the popular open-source RDBMS.
1
vote
1answer
17 views
ERROR 13 (HY000) When Creating Database
I'm trying to create a database and when I type in CREATE DATABASE epik; I get the error ERROR 13 (HY000): Can't get stat of './epik' (Errcode: 13) I am running kubuntu 13.04 with mysql 5.5.31.
0
votes
0answers
26 views
Do certain string patterns affect query performance on a VARCHAR column?
I am a beginner on MySQL Administration and performance problems. Now this is confusing me.
I have a VARCHAR column identity, the string in it is consisted of a Class type and an id, like note:123, ...
1
vote
0answers
38 views
ORDER BY optimization issue
I have a query:
SELECT
user_details.id , user_details.first_name , user_details.last_name,
user_accounts.name account_name, jtl0.account_id account_id,
user_details.title , ...
1
vote
1answer
25 views
Errors while creating multiple mysql-5.5 instances
I have installed 3rd mysql instance on my testing server.
2 instances already running without any issues.
When I installed 3rd instance by mysql-5.5.30 zip source, it installed successfully but when ...
3
votes
1answer
34 views
skip columns while using LOAD command mysql
I have a csv file having 5 columns and i want to load only one out of that, is there a way i can do it. I want to use LOAD statement of MySQL 5.5
Any pointers are welcomed, help would be much ...
0
votes
0answers
20 views
Commit count while using LOAD statements in MYSQL
I have a very big text delimited file, I am using Mysql LOAD statement but i want to put some commit count, for example if i put commit count 1000 then after inserting every 1000 rows it should commit ...
0
votes
2answers
50 views
How do I use subquery on the same table in MySQL?
I have a query like this which takes a really long time to run. The table is around 4 million rows.
DELETE FROM TABLE WHERE value_was IS NULL OR value_was <= value_now;
I'm hoping I could ...
1
vote
1answer
45 views
datetime vs timestamp in mysql 5.5
What is the difference between datetime and timestamp in MySQL with respect to data being inserted from different timezones? Does anyone have any clues on this?
I have a situation where I am trying ...
0
votes
1answer
25 views
Unable to use mysql_upgrade:
I updated mysql recently and found problem related to privileges and backup. When I am using mysql_upgrade command it says-
mysqlcheck: Got error: 1064: You have an error in your SQL syntax; check ...
0
votes
1answer
33 views
Having too many connection problem
We have an magento store and having 9K products and 2 store views the trouble is we are getting too many conection error while the site is in normal loads.
1) We have 100 connectoin open in mysql.
2) ...
0
votes
1answer
39 views
Dealing with empty strings while loading a table from a CSV
I am trying to load a CSV file into a table. The CSV file contains some empty strings for example:
1,2,,4
I want to load the empty field as null. One way I know is to use \N i.e:
1,2,\N,4
but it ...
0
votes
1answer
30 views
In place upgrade from MySQL 5.5 to 5.6.11 removes all users from user table
On Windows, I upgraded from 5.1 to 5.5 no problem.
Copied my 5.1 data folder into my 5.5 instance
Started mysqld skipping grants
Ran mysql_upgrade
All good, but going from 5.5 to 5.6:
Copied ...
0
votes
0answers
18 views
Should store procedures be cached?
Should store procedures be cached in MySQL? If so, How long it is stay in cache?
In my case, When I call one stored procedure first time, it is giving me results in 1 second, after that it gives me ...
1
vote
1answer
68 views
Should I increase max_connections in AWS RDS t1-micro for MySQL?
I have an AWS RDS t1-micro running MySQL 5.5. It gives me too many connections error. I checked and it allows 34 maximum connections concurrently. What I have read is that i can increase this max ...
1
vote
1answer
37 views
Table corruption: How to perform Innodb Checksum checks in MySQL 5.5 for Windows?
Having a corrupted Mysql 5.5.31 (Windows) database, my question relates to the the top solution provided in How do you identify InnoDB table corruption? , more precisely to the following script that ...
0
votes
0answers
35 views
Select query very slow [duplicate]
I have a query which is take less then 0.15ms to execute on mysql on local box. Same query takes 0.348 to 0.468ms to execute on RDS medium instance. Both has same table schema, indexes. Infect on my ...
3
votes
3answers
89 views
Issue after moving the ib_logfile1 and ib_logfile0 files
I wanted to increase the innodb_log_file_size for better performance. And I increased it from the default value to 256 MB. As usual I got the error saying InnoDB: Error: log file ./ib_logfile0 is of ...
1
vote
1answer
48 views
MySQL localhost vs Amazon RDS instance
I am seeing unexpected behavior with some MySQL performance.
When I run a simple query SELECT 1; on my local host (MySQL 5.6.x) using workbench, it executes in 0.000s, but the same query run on ...
2
votes
1answer
59 views
Problem in Fetching Result set in Desired Format
I have 2 tables having the following columns
Person
------
person_id,
first_name,
middle_name,
last_name
Items
-----
person_item_id,
person_id,
item_type,
status,
ordered_date
The query is
...
1
vote
2answers
57 views
How to avoid lagging when enabling log-slave-updates?
Master:
48GB RAM
16-core
my.cnf: https://clbin.com/hlkUo
Slave:
64GB RAM
24-core
my.cnf: https://clbin.com/viLm0
Both are running 5.5.28.
For the incremental backup purpose, I need to enable ...
1
vote
0answers
28 views
Repeated values in group_concat
I have two tables, first the table food and Second is Activity:
INSERT INTO food
(`id`, `foodName`)
VALUES
(1, 'food1'),
(2, 'food2'),
(3, 'food3'),
(4, 'food4'),
(5, ...
1
vote
1answer
28 views
Identical subquery optimisation in an update
update activitybooking set `submitted`='1' where id='958'
and (select SUM(pool1_count) from (select pool1_count from `activitybooking` where `abt`='12' and
(id='958' or ...
0
votes
0answers
31 views
MM Replication and Zabbix in slave, Error code 1032
I have multi-master replication and using Zabbix for server monitoring. Since the replication is row based, I get this error in slave everytime which also breaks my replication. The error I get is:
...
0
votes
1answer
34 views
Optimizing Query
Can anyone help me tuning this query.....
explain extended
SELECT DISTINCT a.msisdn FROM `std_msc_opr_wise` a
LEFT OUTER JOIN
(SELECT msisdn
FROM as_treat_pre_usage_30days
GROUP BY ...
0
votes
2answers
45 views
Unable to drop the table since its showing waiting for meta data lock
We are trying to drop one table but it's getting hanged, and when we see the 'SHOW PROCESSLIST' command it's showing as 'waiting for meta data lock'. Even we are unable to perform any operation on ...
0
votes
1answer
49 views
Creating a partial unique constraint for MySQL
I have the same question as asked in a previous post: PostgreSQL multi-column unique constraint and NULL values. But the solution there is not applicable as I am using MySQL instead of PostgreSQL.
My ...
0
votes
0answers
28 views
MySQL replication is not happening when piping sql into mysql client
Today I noticed a very strange issue where if I cat a SQL file and then pipe it to MySQL client, replication doesn't happen. These MySQL statements aren't also written to the binlog. But replication ...
0
votes
1answer
43 views
Database migration, how to
I have two databases DB1 and DB2. In both databases exists this two tables mo_sms and mt_sms. This is the structure of those tables:
CREATE TABLE IF NOT EXISTS `mo_sms` (
`id_MO` int(11) unsigned ...
1
vote
1answer
47 views
MySQL replication — issue with mysql.proc during replication from 5.0 to 5.5 host
We are replicating from a mysql 5.0.45 host to a 5.5.26 host over WAN. Every once in a while one of our databases does not accept a query and halts the replication.
"'Column count of mysql.proc is ...
0
votes
1answer
40 views
Misunderstanding statement in MySQL documentation
I can't understand this statement in Optimizing Data Size:
Declare columns with identical information in different tables with
identical data types, to speed up joins based on the corresponding
...
0
votes
0answers
21 views
ERROR while doing coalesce partition Mysql Cluster
My table contains 3299000 rows. My Mysql Cluster contains 2 storage nodes with NoOfReplicas=2. By default it contains 2 partitions and after that i added 3 partitions more one by one using command ...
0
votes
2answers
61 views
Steps to upgrade MySQL from version 5.0 to version 5.5
I have been developing under MySQL v5.0 for a while now and need to upgrade to v5.5 to be in step with the hosted production server.
After having searched for precise steps to do this migration, I am ...
0
votes
1answer
78 views
Amazon RDS MySQL performance issues
I have published my website on Amazon EC2 (Singapore region) and I have used MySQL RDS instance for the data storage. Everything is working very fine except performance.
It seems that all queries, ...
0
votes
2answers
51 views
Error log - What does this mean and what can I do about it?
I have the following repeated errors in my error.log and I don't know what it means or what I should/can do about it:
Access denied for user 'root'@'[some IP]' (using password: YES)
There are ...
1
vote
1answer
69 views
MySQL users corrupt
I have a strange situation here:
From time to time I cannot log in with any of my mysql users. I even cannot make a mysql dump.
So I started searching in mysql files and I found that users.MYD and ...
3
votes
1answer
72 views
In MySQL, does the order of the columns in a WHERE clause affect query performance,why?
I have a query that doesn't use any indexes:
SELECT 32,
guid,
1,
1,
1,
0,
5
FROM test
WHERE level >= 20
AND ( ( fun_GetIndexValue(data, 354) ...
0
votes
1answer
37 views
Redo Logs Mysql Cluster
The mysql cluster has 4 directories namely D8 D9 D10 D11 for redo logfiles.
But while inserting into table only one redo directory is used.
I ran following command to get redo information "all dump ...
1
vote
0answers
23 views
Error in alter table reorganize partition for MySQL Cluster
My cluster contains 48 million rows and cluster contains 4 storage nodes . After that I add online storage node and executed alter table 'customer_tbl' reorganize partition.
Some parameters of ...
0
votes
0answers
24 views
After optimize table statement my data usage increased Mysql Cluster
I deleted 500000 rows in my mysql cluster table having 12468000 rows and then i tried to OPTIMIZE TABLE so that all the freed up data memory can be used by another table also, but after optimizing ...
0
votes
0answers
18 views
Re-use disk data extents after delete Mysql Cluster
In my mysql cluster i have 1 million rows and my disk data tables are using all the disk usage available to them ;i.e; free extents are 0 . Now i deleted 50K rows from ap_perf_tbl but still it show ...
0
votes
0answers
20 views
Why data usage increases when deleting rows Mysql Cluster?
My mysql cluster data nodes data usage increased to 95%. Then i tried to delete 500000 rows and my data usage of nodes started increasing initially and reached to 99% and above and TABLE FULL error is ...
1
vote
1answer
43 views
Changing TEXT to VARCHAR
In a MySQL database (InnoDB) we have a table containing roughly 60.000.000 rows. One of the columns is of type text.
Currently the longest entry has length 360 (found using SELECT MAX(LENGTH(value)) ...
0
votes
0answers
46 views
Mysql query is very slow
I am developing a website like any other social networking site using mysql.
I wish it give people suggestion to my users, and I have implemented this functionality in my application, but It is ...
3
votes
1answer
97 views
MySQL Stress testing issues?
I had gone through MySQL High Performance book Chapter 2 for MySQL Bench marking and Profiling,I have some questions about benchmarking
How can we test an existing database and queries against it ...
1
vote
1answer
158 views
increasing mysql table open cache?
I often read that it is best to increase this variable slowly. Can someone explain why? My status indicates that I should increase it... What is best practice / "slowly"?
Thanks!
0
votes
2answers
77 views
Should I disable triggers, timestamps in a slave in mysql?
We're using MySQL. We have a master that eventually will have 2 slaves. There are triggers in the db that execute when data changes in certain tables. I am wondering whether to disable the triggers in ...
1
vote
1answer
86 views
select count(*) in mysql 5.5 innodb— rewrite advice?
I need advice on how to rewrite a select count(*) query for innodb tables mysql 5.5. in new environment its very slow...
select count(*)
from mails3
join questions using (question_id)
where ...
0
votes
1answer
28 views
Reinsert data in new table with new IDs
I have the following two tables:
buynsell
CREATE TABLE `buynsell` (
`id` VARCHAR(20) NULL DEFAULT NULL,
`msg` VARCHAR(255) NULL DEFAULT NULL,
`date` VARCHAR(25) NULL DEFAULT NULL,
...
0
votes
1answer
41 views
Limit Access To mysql information_schema
In case of mysql attacks, many times user extracts information from information_schema.
can i do something in mysql that can restricts user to xtracts information from information_schema while all ...
1
vote
1answer
53 views
Data usage increases initially when reorganize partition mysql cluster
In my MySQL cluster, the data usage of 4 data nodes is approximately 77%. I added a new data node online, and attempted to reorganize partition to redistribute data among all data nodes.
But before ...
