MySQL 5.5 brought many performance enhancements and expanded the feature set of the popular open-source RDBMS.
0
votes
0answers
29 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, ...
0
votes
1answer
18 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.
1
vote
0answers
39 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 , ...
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
...
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
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 ...
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 ...
5
votes
1answer
217 views
effective mysql table/index design for 35 million rows+ table, with 200+ corresponding columns (double), any combination of which may be queried
I am looking for advice on table/index design for the following situation:
i have a large table (stock price history data, InnoDB, 35 million rows and growing) with a compound primary key (assetid ...
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) ...
2
votes
3answers
447 views
MySQL optimization - year column grouping - using temporary table, filesort
I have a transactions table which is having 600,000 records, I need to list the count for the dashboard on financial year basis. The table used is MyISAM. I tried adding index for the transaction date ...
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
2answers
51 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 ...
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
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
37 views
Strange characters in mysqlbinlog output
Has anyone experienced this? Data replicates fine but when output in mysqlbinlog there are hidden characters that break the input?
mysqlbinlog Ver 3.3 for Linux at x86_64
mysql 5.5.28 server
...
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
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
0answers
432 views
1286 - Unknown storage engine 'InnoDB'
I am trying to use roundcube and it recently just broke. I don't know if this is due to a MySQL update that happened recently or not but in phpMyAdmin I get the following error if I try and view a ...
0
votes
1answer
66 views
How to removing or reduce the size of redo logs in MySQL cluster
Can anybody tell me that how can we reduce the redo log file size or can we remove the redo log file size in MySQL Cluster and also what will be the impact of it on performance of cluster.Also can we ...
0
votes
1answer
59 views
Breaking Semisynchronous Replication in MySQL 5.5
I've set up Semisynchronous Replication between two MySQL 5.5 servers running on Windows 7.
My application is running and updating the database of the master server and same is being updated in the ...
1
vote
2answers
194 views
MySQL-5.5 InnoDB memory issue
Version in use is mysql-5.5.24.
In the Enterprise version of MySQL innodb_buffer_pool space is released after a while, however this does not appear to be happening in the community version.
I am ...
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 ...
1
vote
1answer
72 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
163 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!
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 ...
2
votes
1answer
96 views
innobackupex is failing while exporting backup
I am using perl script which is working fine in one of my other box which used to take individual schema backups & finally take all schema together using percona innobackupex.
I have following ...
1
vote
2answers
115 views
MySQL information_schema doesn't update
I have a database, say abc, in mysql server. It has only one table named test. test uses innodb engine and I've set innodb_file_per_table to true.
After I run the query delete from abc.test, I want ...
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
91 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 ...
0
votes
2answers
153 views
MySQL Table not repairing
Table info:
Database name: user_motiva
Table name: wp_options.frm wp_options.MYD wp_options.MYI wp_options.TMD
when I do a mysqlcheck -r --all-databases it gets hung on that table even if you ...
0
votes
3answers
48 views
Using MySQL InnoDB as an Archive
My site has a main MySQL InnoDB table that it does most of its work on. New rows get inserted at a rate of 1 million per week, and rows older than a week gets moved over to an archive table on a daily ...
0
votes
1answer
151 views
Error 1044 Access denied to user
This is driving me crazy.
When I try to create a few tables from my Workbench model I get this error 1044.
I've been trying to find a solution but nothing works for me.
Curiously when I run ...
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 ...
1
vote
1answer
235 views
InnoDB - How to get top locked tables and rows which are locked
I was searching for a tool OR query which can give me top locked tables and which particular row is locked, Is it possible to get ?
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:
...
1
vote
1answer
55 views
INSTALL PLUGIN 'rpl_semi_sync_master' SONAME 'semisync_master.so' not working
I'm trying to install semi synchronous replication in my mysql 5.5 and trying to execute the below command:
INSTALL PLUGIN 'rpl_semi_sync_master' SONAME 'semisync_master.so'
but this command is ...
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 ...
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 ...
2
votes
1answer
60 views
MySQL specific database configuration file
In MySQL's configuration file I've globally disabled autocommit as so.
[mysqld]
autocommit=0
I need to turn MySQL's autocommit on for a specific Ruby on Rails database though. It could be for the ...
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 ...
1
vote
2answers
268 views
SUPER privilege not defined for master user in Amazon MySQL RDS
I have created one medium instance on amazon rds in asia pecific (singapore) region. i have created my master user with master password. and it is working/connecting fine with workbench installed 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
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 ...
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
132 views
consequences of using “innodb_flush_method = O_DIRECT” without having a battery backed write cache? or on a KVM guest?
Mysql 5.5.29 Innodb- 128GB Ram - 32 cores - Raid 10 SSD.
Our server which is a dedicated KVM guest on a 'baremetal' is hosting our heavy read-write DB server.
Everything is file-per-table. ...
1
vote
1answer
292 views
“Lost connection to MySQL server during query” error
I have MySQL 5.5.20 and this table:
mysql> desc country;
+----------------+-------------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
...
