The tuning tag has no wiki summary.
4
votes
3answers
366 views
Are individual queries faster than joins?
Conceptual question: Are individual queries faster than joins, or: Should I try to squeeze every info I want on the client side into one SELECT statement or just use as many as seems convenient?
...
0
votes
0answers
72 views
InnoDB tuning with 1G of ram limit
I am trying to calculate variable moving averages crossover with variable dates.
That is: I want to prompt the user for 3 values and 1 option. The input is through a web front end so I can build/edit ...
0
votes
0answers
29 views
mysql: how many disk seeks were made for a select query
I will fire a select query. I want to know how many disk seeks does that query take.
mysql documentation has given formula for full table scan. ...
4
votes
2answers
243 views
How to Correctly Estimate the Average Number of I/O Operations my RAID 10 disk can offer?
The average Input/Output Operations per Second a disk can sustain is a very important factor in the tuning of MySQL / InnoDB databases, as it drives the speed with which Dirty InnoDB Buffer Pool pages ...
0
votes
0answers
53 views
PostgreSQL can't start after tuning some options
I'm having some issues with "too many clients" and I tried to change the max_connections param (currently 100). I tried to set some value like 300, but when I restart the service, I got this
...
1
vote
1answer
127 views
Slow queries to remote PostgreSQL db
I am running a Drupal site that is backed by Postgres. This is my first time running something with Postgres; I come from the MySQL world.
For doing dev work on the site, I connect to a VPN and ...
1
vote
1answer
211 views
MySQL 5.5 - determining correct write[read]_io_threads on high-end system?
Specifically dual-CPU 32 core - 128RAM - RAID 10 SSD . Ubuntu 64 server.
Heavy Innodb load at times - ~ 2000+ queries per sec. Heavy read and write.
Currently we are running on the default ...
2
votes
1answer
924 views
MySQL 5.5 - Innodb - innodb_log_file_size higher than 4GB combined?
When reading online about innodb_log_file_size, it says
The combined size of the log files must be less than 4GB
So what happens if it needs to be larger?
In books and online, it says to set ...
0
votes
1answer
1k views
Mysql 5.5: Optimizing all tables with mysqlcheck - is it useful to run the -check option along with -optimize?
I plan on running 'mysqlcheck --optimize --all-databases' to clear up some fragmentation.
Would it be useful to run -check with this option or does the -optimize already take care of that?
I am only ...
1
vote
1answer
55 views
tuning feed item's table query with multiple condition
I have a query like this:
SELECT *
FROM `rss_item`
WHERE `feed_id` = 1 and `timestamp` < 1350698635
ORDER BY `rss_item`.`timestamp` ASC
MySQL: 5.1; table engine: innodb
Explain result:
...
0
votes
2answers
179 views
Tuning query to remove joins for reporting
This is the query I was sent. There is currently no data in the system as I was converting this query from teradata to SQL server.
SELECT user_id FROM user_table
LEFT OUTER JOIN
(
SELECT user_id , ...
0
votes
0answers
283 views
Oracle 10g - Sudden change in execution time for specific query
After the DBAs fiddled with some parameters in our Oracle 10g Production Environment, most queries became a little faster. But a single query (a quite complex one) became dramaticaly slower - it went ...
1
vote
1answer
550 views
InnoDB Performance Tuning
I'm new to database administration so please excuse any omissions of what would seem like basic info to provide for this problem.
I'm a RoR developer and our team is currently short a DBA, so we're ...
5
votes
2answers
348 views
What can I do to speed up this SQL Query?
I've created this SQL query with the help of @Dems :-)
Here is some detail, I tried to make a SQLFiddle but I kept getting errors with my variables... This works in Sql Server 2008... My question ...
2
votes
2answers
749 views
MySQL 5.1.63 - using tuning-primer - Table Cache question
tuning_primer says the following:
TABLE CACHE
Current table_open_cache = 812 tables
Current table_definition_cache = 256 tables
You have a total of 498 tables
You have 812 open tables.
Current ...
4
votes
2answers
904 views
How I should fix the following update statement to make it run faster?
I have the following DML:
UPDATE rc_usutb011 u
SET cod_ant=(
SELECT cod_hst
FROM rc_pdptb101 p
WHERE ocip_hst=ocip_ant
AND p.sector=u.sector
);
The explain plan ...
5
votes
2answers
4k views
Learning to Optimize SQL Queries and Understand Execution Plans - Resources?
I find myself writing more and more SQL queries at work (mostly Oracle 11g, but some SQL Server 2005-2008) and have started creating some pretty complex views for the rest of the analyst team.
They ...
3
votes
1answer
727 views
Pgpool, Postgresql and Apache tuning (1000 concurrent spatial queries)
I'm trying to configure a load balancing system.
I've a python script, invoked through mod_wsgi on Apache, that generates a query and executes it on pgpool: request-> wsgi python -> pgpool -> ...
1
vote
1answer
361 views
Improve performance for my plsql block
First of all let me make kind of a disclaimer here:
1) i'm a developer, not an administrator;
2) and i dont have admin rights on my database.
3) table specs :
-- oulp_path_attendance_base_t - ...
4
votes
1answer
572 views
Tuning dedicated Percona Server with XtraDB for OLTP
Hardware specs for an OLTP DB
dual quad core xeon with hyperthreading
24GB ram
Hardware RAID10 BBU
Software specs
Standard install of Ubuntu 10.04LTS with default LVM partitioning
Installed ...
2
votes
1answer
214 views
SQL Server 2008 R2 DETA Error: Can not get minimal database information in allotted time
I have a 18,6 GB SQL Server 2008 R2 profiler trace file. Trace file recorded at tuning profile. When I submit this trace file to database engine tuning advisor I get this error:
Error: Can not get ...
16
votes
3answers
17k views
Possible to make MySQL use more than one core?
I've been presented with some dedicated MySQL servers that never use more than a single core. I'm more developer then DBA for MySQL so need some help
Setup
The servers are quite hefty with an ...
5
votes
2answers
513 views
DTA Recommends to CREATE STATISTICS
I just ran a T-SQL query through DTA and one of the recommendations is to CREATE STATISTICS on one of the columns that is part of many of the queries in the SQL code file.
My question is, how exactly ...
1
vote
1answer
116 views
Can SQL profiles be deployed to other Oracle Databases?
When using The SQL Tuning Advisor in SQL-Developer. I get often some recommendations to accept a SQL-Profil. I guess it is a good idea to do so.
But is this similar to proposed indexes, which I can ...
