MySQL 5.5 brought many performance enhancements and expanded the feature set of the popular open-source RDBMS.
0
votes
0answers
10 views
Having trouble connecting tungsten replicator from EC2 to RDS
I am testing using Tungsten Replicator to help migrate large databases to RDS. I have no trouble setting up the service on the EC2 "master". I am using a second EC2 instance as a kind of relay server ...
0
votes
1answer
23 views
Select unique value whereas the time is highest in the most optimal way
Given a simple, with a text and time column, I want to select X unique values from the text column, whereas that row contains the highest value for time.
INSERT INTO `test` (`id`, `text`, `time`)
...
0
votes
1answer
26 views
How to run a SELECT query within while loop in PHP?
Within a SELECT query via PHP while loop, I need to run a mysql SELECT query as
$result1 = $mysqli->query("SELECT * FROM table1");
while ( $row = $result->fetch_assoc() ) {
if ( $row['X'] == ...
3
votes
1answer
32 views
Getting Random Sample from large database MYSQL (No Auto Inc Field)
You were so helpful with my last question, I thought id throw another one at you thats stumping me.
Basically I got a table, requirements from company was it was all supposed to be 1 table so I got ...
1
vote
1answer
23 views
Is there a way to find the least recently used tables in a schema?
Is there a way to find the least recently used tables in a MySQL schema? Besides going into data directories? I was hoping there was a metadata or status trick-- but Update_Time in STATUS and ...
0
votes
1answer
63 views
Am I wrong in table design or wrong in selected index when made the table?
I've build web application as a tool to eliminate unnecessary data in peoples table, this application mainly to filter all data of peoples who valid to get an election rights. At first, it wasn't a ...
0
votes
1answer
16 views
HOW to “SUM” and “JOIN” for single query of a poll results?
I have a poll database as
CREATE TABLE poll_answer
answer_id,
answer varchar(255),
poll_id int(11),
FOREIGN KEY(poll_id) REFERENCES polls(poll_id) ON DELETE CASCADE,
PRIMARY KEY(answer_id)
) ...
-1
votes
2answers
60 views
Help my database isn't performing fast enough! 100M Merge with 6M need < 1 hour!
I have a server right now receiving more raw data files in 1 hour then I can upsert (insert -> merge) in an hour.
I have a table with 100M (rounded up) rows. Table is currently MyISAM. The table has ...
0
votes
0answers
38 views
Replicate database without Internet connection
I'm working on a company where I have a central DB and several agency databases. See the diagram at here. All the databases are identical, just the data can change and in some cases. I've no internet ...
0
votes
1answer
33 views
MySQL+Web-App Performance Issues using different servers
We are having a performance issue with our MySQL servers that does not make any sense. I have read countless articles from many people (mostly Percona) and have made my.cnf tweaks. We have even manage ...
2
votes
1answer
38 views
MySQL Subquery hangs / terrible perfomance
I am using MySQL 5.5.16 @ CentOS.
Please have a look at this query:
SELECT
inventory_ID,
(
SELECT
price_brutto
FROM
_inventory_prices
...
0
votes
1answer
46 views
Is it possible to force drop of mysql tables with FK?
For dropping a table in which a Foreign Key is used in other tables, it is necessary to drop all other tables having FK connection with the corresponding table.
Is there a short way to drop a table, ...
0
votes
1answer
36 views
Will Partitions and Indexes on the same table help in performace of Inserts and Selects?
I have a table containing the list of visitors and this table has the following information.
Visitor Browser Information
Visitor Location Information
Visitor Time Information
No of Visits
I have a ...
1
vote
2answers
27 views
Innodb table is taking randomly long time to execute the insert query and in show processlist showing as queryend/updating
Innodb table is taking randomly long time to execute the insert query and in show processlist showing as queryend/updating and it happens for the similar queries for the same table and the queries got ...
0
votes
1answer
26 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
1answer
43 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
1answer
53 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 , ...
0
votes
1answer
53 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
39 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
22 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
75 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
60 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
36 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
38 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
50 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
75 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
19 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
179 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
47 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
125 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
54 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
63 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
65 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
30 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
42 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
35 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
62 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
52 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
30 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
50 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
56 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
41 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
29 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
71 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
97 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
54 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
81 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
78 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) ...
