0
votes
1answer
16 views

Last row from a query without Order by

I have something like SELECT var1,var2 FROM table where var3=X AND var4=Y order by var5 desc limit 1; Running this query takes roughly 5 seconds on my database which is far to slow. I was ...
1
vote
1answer
37 views

A table that consists of multiple FK or creating separate tables for each FK

I have tables called 'books', 'category', 'subcategory', and 'booksCategory'. Each book can have its own category and subcategories. For example, a Sci-Fi book can belong in the 'category' table under ...
0
votes
1answer
19 views

How to optimized mysql query having large dataset

I have two tables in MySql with the following schema, CREATE TABLE `open_log` ( `delivery_id` varchar(30) DEFAULT NULL, `email_id` varchar(50) DEFAULT NULL, `email_activity` varchar(30) DEFAULT ...
0
votes
1answer
43 views

A single, simple update takes 10+ seconds

We are running MySQL 5.1.71-log and have a table with 2.7 million rows. Simple updates to it are regularly taking more than 10 seconds to execute. The table structure is: CREATE TABLE `person` ( ...
0
votes
0answers
20 views

Help with MySQL query which is only occasionally slow? Temp tables/Disc caching?

We have an issue with one particular query whch runs regularly on our MySQL database, though I am not necessarily sure it is a problem with the query itself. 90% of the time it runs perfectly fine ...
0
votes
1answer
63 views

Help optimizing very slow mySQL query

I have a query which takes about 6 secs to execute. SELECT * FROM (SELECT ord.ID, op.name AS prodName, op.code, ord.date, ord.email, op.total, stat.ID AS statusID, stat.value AS status, ...
0
votes
0answers
18 views

Select changes in table by date

I have following table schema name type id int key string count int date date url_id id with example data id key count date url_id 1 system 100 ...
1
vote
1answer
35 views

Mysql super slow

I have a database of movies that I downloaded, it is around 51mb in size. One of the tables has more than 750k records(all separate insert statements(I believe this is bad)). The rest aren't so bad ...
0
votes
0answers
30 views

Slow query (Wordpress)

Can I speed up somehow the following query? Somehow to stop from creating a tmp table/filesort. Tried a couple of indexes but no luck. mysql> explain SELECT wp_posts.ID FROM wp_posts LEFT JOIN ...
1
vote
1answer
30 views

What is the generally accepted method and tools for profiling MySQL queries?

Profiling database queries is difficult, and dependent on database technology. In MySQL, what is the usual (or, in deference to that, a great) process for profiling a query? For example: Run the ...
1
vote
1answer
36 views

Difference between DATE(time_field) AND time_field in a WHERE clause

I have 3 tables: users movements unique_ids I want to get the records gotten from march until now of the users registered in march, counting the unique id of their movements with a distinct and the ...
0
votes
3answers
57 views

How to return last used record?

I have simple table called ips with 2 field ip and address, which schema is following CREATE TABLE IF NOT EXISTS `ips` ( `id` int(10) unsigned NOT NULL AUTO_INCREMENT, `address` varchar(255) ...
0
votes
2answers
39 views

Increased query_cache_size, Queries slowed drastically on increased traffic

I increased our servers query_cache_size to 2gb, hoping for performance benefits. After sometime the query performance would drastically decrease. Once I dug in deeper, I found the queries in State ...
0
votes
1answer
50 views

Select from a list of values from JSON encoded data

I have saved the details of the product in JSON format. I am wondering how to select from a list of values from a "JSON_ENCODED DATA" For Example I want to select TV with screen_type as LED or LCD. ...
2
votes
2answers
60 views

Super simple mysql query taking too long

I have the following: SELECT * FROM autorepair WHERE zip_code IN (91316,91356,91416,91426,91436) AND specialty = 'transmission' ORDER BY ABS(91316 - `zip_code`) LIMIT 0,10 Indexes: -zip_code ...
0
votes
1answer
39 views

How to optimise very simple query with subquery that only needs to execute once

SELECT products_id, products_model, products_iban_no, products_allocation_number FROM products WHERE products_model IN (SELECT products_model FROM products GROUP BY products_model HAVING ...
0
votes
1answer
52 views

How can I write queries as fast as possible in MySQL?

I'm looking for two things: Awesome manual about writing fast MySQL queries. Tool which will decompose my query into discrete steps, and give estimations of each step. I've seen the next tool, ...
1
vote
1answer
57 views

Improve select query performance

The following select query from my application is taking more than 200ms. The table has around 2 million rows. Is there any ways to improve the performance of this query ? select count(id) from ...
1
vote
1answer
65 views

Performance issues when extracting scatter plot data

First off: Sorry for the title, couldn't think of anything better. Feel free to change it though. Ok, assume I have the following table: ...
-5
votes
1answer
80 views

Recommendation for mysql please :MySQLTuner [closed]

>> MySQLTuner 1.3.0 - Major Hayden <major@mhtx.net> >> Bug reports, feature requests, and downloads at http://mysqltuner.com/ >> Run with '--help' for additional options ...
0
votes
0answers
17 views

Analize Query in MySQL Server 5.1

I try use MySQL Workbench 6 to analyze the cost, but they don't show the cost of query. How i get this costs?
0
votes
1answer
98 views

Improve MySQL Query Performance - Too many records

I am using MySQL RDMS for a contact management system. Now a days my database grew in size and contains more than 1 million records. Checking duplicate phone numbers became a big issue during ...
1
vote
1answer
30 views

Will composite indexes or unique indexes help with query performance?

I need help with identifying indexes to increase performance of the following query. I'm currently using v5.5 with InnoDB. I cannot modify the query. However, I can add indexes as needed. The ...
2
votes
0answers
79 views

poor and/or unreliable InnoDB performance

I recognize that there are a ton of posts like this, but after reading up on InnoDB performance problems, nothing I tried has helped. I have a database containing four InnoDB tables. The largest ...
1
vote
1answer
50 views

Slow queries InnoDB occasionaly

I have the next table: CREATE TABLE `sessions` ( `session_id` char(32) COLLATE utf8_unicode_ci NOT NULL, `session_expires` int(11) NOT NULL DEFAULT '0', `session_data` varchar(10000) COLLATE ...
1
vote
1answer
59 views

LOAD DATA stuck at Null State MySQL

I'm stuck trying to move one table to another, due to columns now no longer having proper references/meaning to their column titles. In doing this, I've created a new table with the same number of ...
0
votes
0answers
66 views

group by and order by making query very slow in mysql?

Query works fast: select SQL_NO_CACHE users.id, users.name from useres left join user_statistics on users.id = user_statistics.user_id where users.is_deleted = 0 group by users.id ...
0
votes
1answer
41 views

Query with INNER JOIN takes long time than expected?

I have the following query, which takes longer than expected. Anybody help me find a faster alternative? SET SESSION MAX_JOIN_SIZE=18446744073709551615; SELECT claims.claim_id, ...
3
votes
1answer
207 views

MySQL queries are 10 to 100 times slower after OS reboot

I have a MySQL server running on Ubuntu. If I restart the MySQL, everything is fine. If I however restart the OS, my queries take anywhere from 10 times to 100 times as long. The only "solution" to ...
1
vote
1answer
80 views

Why does innodb_flush_method = O_DSYNC provide such a performance boost with SAN-backed storage?

I've seen some people suggest that O_DSYNC should be used with a SAN. The MySQL docs have this to say about O_DSYNC in general: In some versions of GNU/Linux and Unix, flushing files to disk with ...
1
vote
2answers
105 views

Why does “SELECT *” take longer than “SELECT <primary_key>”?

I'm having a problem with a query running on a little PHP program. When I use * to select all the columns, it takes way more to return the result than when I use just one column. The query that is ...
0
votes
0answers
47 views

Latest of group in subquery is bottleneck, how to optimizing query?

See Original question I'm fetching the activity data for the latest activity for each company as part of a bigger query. I've been using the method provided by ypercube, and it works fine, but I find ...
1
vote
1answer
896 views

MySQL SQLSTATE[HY000]: General error: 1205 Lock wait timeout exceeded

I have database session enable, when website got thousands of visitor. It gives me error [30-Apr-2014 04:27:12 America/Denver] PHP Fatal error: Uncaught exception 'PDOException' with message ...
2
votes
2answers
384 views

MySQL COUNT Query taking too long time to execute

I have below query that takes 7 secs to run SELECT COUNT(*) AS `count` FROM `yuldi`.`businesses` AS `Business` LEFT JOIN `yuldi`.`businesses_categories` AS `BusinessesCategory` ON ...
0
votes
0answers
22 views

Can't run subqueries on my server (MySQL)

I have a weird problem, where I can run sub-queries just fine on my local machine, however they seem to be hanging forever when I attempt to run them on my server. Note that my server has plenty of ...
0
votes
0answers
31 views

MySql query keep running for a long time

Following query keep running for a long time and I'm using MySql 5.5.34 on XAMPP on Windows SELECT id_package, `pck`.`fk_sales_order`, `pck`.`fk_picklist`, count(pci.id_package_item) as items, ...
1
vote
1answer
67 views

Any idea why this seemingly-simple query is really slow?

Here's the query SELECT count(*) FROM registration r LEFT JOIN registration r2 ON r.baggage_group_id = r2.baggage_group_id AND r2.team_id IS NULL WHERE r.event_id = "102577"; It seems pretty ...
1
vote
2answers
67 views

What's the best way to translate a website [closed]

I have a website in Django using MySQL, and I have more than 4.000 entries that I want to translate. What's the best way to do it? Create a new database for every language? Create other table for ...
1
vote
0answers
76 views

Best database for fast read all in one table

I currently have a large database in SQLite that I was using for rapid-prototyping for a software I am working on. Now that I am planning to move it to another database that should give better ...
0
votes
2answers
167 views

How to fix slow LIMIT queries with big offsets without heavily rewriting them?

Imagine a very basic example of your average discussion board. For example: CREATE TABLE threads ( id INT UNSIGNED NOT NULL AUTO_INCREMENT, title VARCHAR(100), PRIMARY KEY (id) ) CREATE ...
0
votes
0answers
40 views

Big Mysql table optimization

I have a table that I use to cache google translate API answers. Table structure is orig_string and group are indexes Now it has more that 1million rows with 35000 distinct values in group field. ...
0
votes
3answers
65 views

Get only future records

I have the following query: SELECT master.master_id, master.showname, MIN(CONCAT(shows.show_date, ' ', shows.show_time)) AS first_show_date, MAX(CONCAT(shows.show_date, ' ', shows.show_time)) AS ...
1
vote
1answer
53 views

Is there any way to get the estimate cost of executing a query in MySQL?

In PostgreSQL, EXPLAIN or EXPLAIN ANALYZE will show the estimate cost of executing a query. But EXPLAIN in MySQL doesn't provide this information. How can I get the estimate cost without installation ...
0
votes
2answers
46 views

MySQL query optimization for legacy application

I'm working with a legacy application that started out with little data years ago (developed by a third party custom for this client), and now we're seeing MySQL load skyrocket on this query alone. ...
2
votes
2answers
593 views

Optimized query to fetch a record from 10 million entries

A table has 2 fields | UniqueKey | TimeStamp | ------------------------- | xfsddddq | 1024125412 | | xfstttdx | 1024125413 |< | xfsdxxau | 1024125415 | Estimated, there are 10 million ...
1
vote
0answers
53 views

Tagged questions

I have similar to StackExchange network that utilises tagged questions. In my web application Users also can find questions by tags. The query below returns a set of tagged questions: SELECT ...
0
votes
1answer
146 views

Delete millions of rows, fast

I currently have a database with the following structure: id->varchar(9) time->datetime val01 - val20->int(11) val21 - val40->tinyint(1) id and time are the primary key. also I defined an index ...
0
votes
1answer
57 views

Query causing Database lock problem (php/Mysql) [closed]

hi friends can anyone tell me what is the issue with my query. when i execute, it lock the Database for 5 to 10 minutes, please help me to optimize this query . SELECT u.username, ...
-1
votes
1answer
103 views

Approximate MySQL Query Time For A Where Clause On A 10 Million Records Table

I'm looking forward to designing a database (in MySQL) but before I start I need to have some calculations to make sure that my application will remain efficient even if there are 10 Million+ rows ...
-4
votes
2answers
74 views

Performance with IN clause

Does indexed data affect query performance? means If I passed value as 1,2,3,4... in ordered form in any IN clause, can it improve query performance? and what happen in case I pass value randomly ...