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Example Database for tunning

I've been searching for so long and I've still have not found what I'm looking for ,is there any database or similar resource that people uses for tuning a database, or optimize queries?. I would be ...
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3answers
715 views

Oracle Compatible Parameter to set

Is there any difference in setting the Compatible Parameter to 11.2.0.0 vs 11.2.0.4 ? Are there any advantages / dis-advantages ?
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2answers
201 views

Please recommend changes for my.cnf

I am not having any performance problems per se but want to improve my sites' performance if possible. Would appreciate any advice for how I can improve my.cnf. I have just one server, not ...
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4answers
243 views

mysql need help optimizing query

I have a table containing servers logs, and another table containing rules to match certain and drop them. The logs tables contains around 1 million rows, and there are about 20-30 rules. The ...
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5answers
14k views

How to determine the optimal sort_buffer_size?

I read from a sample configuration file which says the following: # Sort buffer is used to perform sorts for some ORDER BY and GROUP BY # queries. If sorted data does not fit into the sort buffer, a ...
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1answer
50 views

Same query same data different server different query plan

I have a query that hits a view, which references other views etc...several levels down. The query plan is a bit complex. I run the query on 2 different servers. On both servers, the number of rows ...
3
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0answers
87 views

Sort operation SQL Server 2012

I am trying to optimize a query and the sort operation (91% cost) is the costliest operation. Any help will be appreciated. Query is : SELECT TOP 1 ArchiveType, CONVERT(NVARCHAR(30), ...
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1answer
92 views

Query tuning issues

I'm in trouble trying to tune this following query. I used to be 100% focused in the infrastructure side of the stuff, but since August this year I'm working for a processing card company that is ...
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1answer
35 views

Query speed improvements [closed]

Referencing: CREATE TABLE words ( word_id int(11) NOT NULL, word varchar(25) NOT NULL, PRIMARY KEY (word) ) CREATE TABLE synonyms ( source_index int(10) unsigned NOT NULL, ...
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0answers
62 views

Postgresql configuration for tiny server and append-only data

Currently my database is runing on tiny-sized hardware (digital ocean 5$) and I want to keep this hardware. It is: 512M memory 1 CPU My database works with these conditions: Data is never ...
2
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3answers
295 views

Export Query Plans

I know it is very easy to export a single query plan. My question is, when I create a query which returns multiple plans, such as looking at the most costly queries on the server, is there a way to ...
21
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4answers
21k 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
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1answer
176 views

Performance tuning in Sybase

Does Sybase have a tool like AWR in Oracle which can be used to identify high load SQL, tell the important waits that are happening, help in understanding the workload? What are the main tools to be ...
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0answers
160 views

Tuning MySQL with InnoDB engine for my application

I've read through a lot of answers, and I realize this is mostly application specific, so I wanted to give some background as to what I'm doing with the database and hopefully get some tips on tuning ...
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2answers
98 views

Database Tuning Issues

I'm not a DBA so looking for some advice on tuning a MySQL (MyISAM) database. I've found that during peak hours we are getting pretty severe load spikes which are slowing down the web front-end. I've ...
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0answers
595 views

Low Query cache efficiency after mariadb 5.5 migration

We change from Percona MySQL server 5.5 to MariaDB but performance is not as good as we think. This graph is from a day in MariaDB. You can see the low performance in terms of cache_hits: We have ...
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1answer
65 views

Confused over table_open_cache

I've been reading about the table_open_cache and I'm slightly confused about how big it should be, I've seen conflicting advice. My DB is running on MyISAM and has 199 tables. I ran into an issue ...
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0answers
109 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. ...
3
votes
1answer
154 views

How to monitor load on database server

Could anybody please suggest me a way to monitor the load on my database server? What perfmon counters should I monitor on daily basis and confirm that load on the server is increasing day by day [or] ...
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2answers
116 views

Seeking help to test a use case on sql server memory

This is a question which came out of curiosity to know of how SQL Server handles memory. Assume I set a very low value for max server memory and I increase my workload like running dbcc checkdb, ...
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4answers
106k 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 ...
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2answers
4k 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 ...
1
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1answer
354 views

Why the optimizer does not use an Index Unique Scan?

I am on Oracle 10.2.0.4.0. I have a big Index Organized Table (IOT) with 74 columns and over 345 million of rows. An external tool execute a batch where I cannot touch the source code. The critical ...
2
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2answers
465 views

SQL Backup tuning large databases

I am tuning SQL backups using compression, writing to multiple files, and changing the BufferCount and MaxTransferSize options. I have SQL instance with a 4 TB database and several smaller databases ...
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2answers
4k 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 ...
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1answer
134 views

Why isn't this index helping my InnoDB MySQL query?

I'm having trouble understanding why an index I have on one of my tables is doing nothing to help the performance of a JOIN, even when forcing the index. Here is the query: EXPLAIN SELECT * FROM ...
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1answer
202 views

DB2 LUW Query Optimization - IXSCAN timerons greater than total timerons

Sorry - I feel like this is a newb question, but I can't find anything on it. In optimizing a query, I was able to apparently reduce the total timerons from 3,700 to 38. However, on closer examination ...
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0answers
294 views

No query cache efficiency mairaDB

I'm totally new to database tuning, and even though I've done well so far, I'm stuck with my database cache query efficiency 0%. Any help with this would much appreciated I've tried increasing ...
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0answers
88 views

Optimization of an old query multiple unioned subqueries

I am currently in the process of optimizing a large query that was written for oracle 8i. My company currently uses oracle 10g which gives us a lot of options for optimization. Please Reference the ...
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2answers
170 views

How do dirty reads at both the transaction and table level provide increased performance?

I ran the following code past our architect as I thought there may have been a tautology between the isolation level and table hint: SET NOCOUNT ON SET TRANSACTION ISOLATION LEVEL READ UNCOMMITTED ...
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2answers
601 views

Oracle 11.2 using too few memory

it is about one year that I have changed my server from Oracle 10g to 11.2g (and also changed the hardware and Windows from 2003R2 to 2012). The problem is that with more than doubled cpu power, ...
6
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5answers
1k views

Performance tuning a Great Circle distance calculation

I have a query that I am using to find locations that are within 1km of a known point. To do this, I am using the Spherical Law of Cosines formula with my latitude and longitudes. Currently, the ...
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2answers
3k views

Percona Xtradb Cluster : How to speed up insert?

I recently installed a 3 full master node cluster based on Percona Xtradb (very easy install). But now i need to make some tuning to increase INSERT/UPDATE requests. Actually, i made around 100 ...
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2answers
724 views

Tips on using SQL access advisor in Oracle

Please share how to use oracle SQL access adviser for single or multiple queries. you can assume that we know the sql ids for the queries we are interested in.
3
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1answer
2k views

Tuning key_reads in MySQL

We are trying to tune our MySQL database (Myisam, 5.1.73) which is getting busy. We investigated Key_reads: $ mysqladmin ext -ri10 | grep Key_reads During a normal load we have the following ...
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0answers
15 views

MySQL: index statistics dropped when table dropped?

When a table is dropped, are its index statistics also removed? The reason I ask is that I was hoping to 'prep' the stats by running log playback via the percona-playback tool prior to cutting over ...
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2answers
11k 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
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1answer
2k views

Pgpool, Postgresql and Apache tuning (1000 concurrent spatial queries) [closed]

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 -> ...
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2answers
111 views

Optimizing UDF - Is Using DUAL Expensive

I am new to Oracle technology (primarily versed in SQL Server) and I am having trouble with the performance of a UDF. The purpose of the UDF is to take some inputs for an "event", and look up an ...
0
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1answer
7k 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 ...
3
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1answer
2k views

Profiling PostgreSQL

We have a system built with Python 2.7, Django, PostgreSQL 9.1 and PostGIS 1.5. In this system there is some extensive validation processes that are, well, intensive. Our machine: SO: CentOS 6 HW: 8 ...
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1answer
2k 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 ...
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0answers
139 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 ...
4
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2answers
3k 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 ...
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0answers
492 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
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1answer
1k 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 ...
2
votes
1answer
6k 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 ...
5
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1answer
10k 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 ...
1
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1answer
108 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: ...
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2answers
460 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 , ...