An evaluation of whether a system works well enough to be fit for purpose. Normally performance refers to the speed with which a system completes an operation or set of operations over time.

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486 views

Select * from statement execute very slowly, innodb io read speed is low

I have a very simple query " select * from ap_statistic " running in my servers. the servers have the same hardware and software configuration (CPU 8 core, mem :32G, OS: redhat 5.5, mysql version: ...
2
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1answer
57 views

What are possible causes for consistently volatile INSERT performance in MySQL tables?

I have a Java program running on a VM that is sequentially feeding a queue of single row INSERTs through a single connection to a MySQL server on the same VM. The queue execution is not artificially ...
2
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1answer
65 views

Will MySQL be effective when selecting a row from a table with billions of records?

Note: this is a hypothetical scenario Lets say that: I'm running MySQL, InnoDB engine, UTF-8 encoding I have a table with 50+ billions of rows The tables primary key is a BIGINT The table also has ...
2
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1answer
155 views

Is this amount of disk IO expected with MySQL?

I am running MySQL 5.5.34 on an Amazon EC2 micro instance with EBS (elastic block storage). The instance has been running for around 10 days and according to Amazon I've accumulated around 8.5 ...
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1answer
66 views

Optimizing large MySQL SELECT WHERE IN clauses

How can the following SELECT WHERE IN case be optimized? I have a table with over 100 million rows with only 3 columns. The primary key (col1) is a 127 varchar. I am performing a SELECT col1 WHERE ...
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1answer
53 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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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 ...
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1answer
134 views

Inserting to table: Insert rows with Left Outer Join or Insert rows then Update?

I have a table of Orders and another table of Deliveries. The Orders table will contain a reference to the Deliveries table if there is a corresponding row. Not every row in Orders will have a row in ...
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1answer
44 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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1answer
108 views

Partition : understanding files and file groups

We are trying to partition a large history table. Being new to partitioning, I was trying to understand the concept of files and file groups. File groups can be set up in following three ways : 1. ...
1
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1answer
182 views

Internal query on CDEF$ and CON$ very CPU bound

I am checking an application (Infor ERP LN) that loads a lot of data into an oracle 10.2 database. While checking one of the user sessions with SQL_TRACE and its output with tkprof, I found that the ...
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1answer
79 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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1answer
23 views

Perl - MySQL/MariaDB - slow with no identifiable bottleneck

I am running a Perl script (using DBI) which reads from raw files from a hard disk, and updates MySQL database (which is on a separate SSD). My performance is rather slow (1000 files processed in ...
0
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1answer
32 views

MySQL ON DUPLICATE KEY UPDATE performance issue

We have a table with over 200k rows. Every row belongs to a category, there are almost 50k rows per category. What is the best way to update all rows of that category? We are using a script like ...
0
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1answer
41 views

Does having a big table that I do not query cause the whole DB to be slower?

I have a log table that I use for logging files sent to clients. I'm not querying that table, just use it for logging (INSERT) and when I need to check when something was sent to clients, usually once ...
0
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1answer
33 views

MySQL 5.1: change datadir variable value in my.cnf

Below is my system configuration: OS: RHEL5 MySQL: 5.1.73 Default datadir=/var/lib/mysql/ But, the above directory has space crunch. So, I decided to change the path. I found /u000 directory has ...
0
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1answer
31 views

Mysql improve Self join performance large table?

I have a task to help identify conflicting IP ranges , I want to highlight when one companies IP range falls within another's ... below is the sample table, I have converted the IP ranges from .dot ...
0
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1answer
26 views

How can I measure the number of IOPs for a certain query

I need to estimate the max IOPs for a certain MySQL DB (one that does not exist yet). The OS is Linux and the DB is MySQL 5.1.x (though I don't think the DB brand is important for the asked topic) ...
0
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1answer
21 views

MySQL 5.1: How to rollback partitioned table

I have partitioned a table on the basis of one flag column have value either 0 or 1. Now, I want to roll back these tables. How can I do this?
0
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1answer
93 views

How to configure my.cnf for Mysql 5.1, which is using too much CPU?

I am new Database engineer. I am having trouble in my server which is using too much CPU on database query(simple count statement). I have googled about it, so i found out it depends on system ...
0
votes
1answer
37 views

Slow INSERT/UPDATE on InnoDB

I have a problem with the performance of my MySQL server, let me explain: I instaled a MySQL server, version 5.5.20 Server version: 5.5.20-log Source distribution SELECT queries runs fast on ...
0
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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 ...
0
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1answer
45 views

How to prepare executon plan for given sql query on a server with 4 processors (Oracle database)

4 processors means the query runs in parallel. Select /*+ parallel(4) */ T1.A FROM T1,T2,T3 WHERE T1.A = T2.A AND T1.B=T3.B AND T1.C=T3.C Tables T1,T2 and T3 have 4,8, and 16 partitions ...
0
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1answer
69 views

Oracle 11g max login fail attempts workaround

My problem with database starts with situation where I cant really modify anything in database. My project specialist has limited time to help me. Here is the thing: My user in Oracle database has ...
0
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1answer
51 views

DB2 - how to track IOPS statistics?

DB2 9.7. Is there some easy way in every moment go have statistics about IO operations per second? I am not interested for hit ration on Buffer Pool but really on IOPS? THANK YOU
0
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1answer
96 views

DB disk space requirements comparision between MySQL versions

I have 2 labs where MySQL is installed. DataBases are created and deleted dynamically by certain internal processes. InnoDB is the Engine used. In one lab, MySQL version 5.0.77 is installed. The DB ...
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46 views

how to design my database for faster reads for my situation

I have a situation where i have two categories. Lets say type A and type B. In my database I have some 50,000 type A entries and 100,000 type B entries as of now. For each entry mentioned above(type ...
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0answers
101 views

Oracle - How can I improve this query?

We have performance problems with some queries. We always use the rank() function to get the latest entries with a status. The question is, how to speed up things. CREATE TABLE PAYMENT ( CLIENT ...
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0answers
129 views

SQL queries are very slow

I have noticed that my queries are getting slower. Some update queries take about 48-50 seconds. Here's how it looks: [root@db-1 ~]# tail /var/lib/mysql/mysql-slow.log # Time: 131113 17:09:48 # ...
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316 views

SQL Server: Batch Requests/sec showed increase in performance, but performance actually decreased

We are currently on SQL Server 2005, with a plan to move to SQL 2012. To make this move we have to test new database drivers for the application (Java). We performed 2 load tests using the 2 different ...
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0answers
52 views

MySQL showing non-linear behavior for a simple insert

I've come across a symptom in MySQL which got me baffled. First, the time it takes to INSERT a certain amount of records changes non-linearily with the amount of records. Second, the time also depends ...
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0answers
101 views

My queries are slow under load

I am performing a load test for my application. All my SQL queries which are fired from my application, individually look better and perform fast. The same SQL are becoming bottleneck when they are ...
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0answers
118 views

mysqldump & upload to mysql speed impact due to SSD and innoDb?

I am testing an AWS Medium Instance with CentOS (AWS AMI) and comparing it with Hetzner's EX40-SSD (http://www.hetzner.de/hosting/produkte_rootserver/ex40ssd). Software setup on both is comparable( ...
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0answers
131 views

PostgreSQL 9.2 (PostGIS) performance problem

A month ago i got acquainted with PostgreSQL and only now i've noticed that some of my queries are pretty slow. Well, for example, i have table: CREATE TABLE sometable ( gid serial NOT NULL, geom ...
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0answers
179 views

Improve Speed of MySQL Database Import

I'm importing around 44 GB (14 million rows) of information into an InnoDB MySQL database, and I'd like to do so in a reasonable timeframe. Since I'm doing this on a personal computer, I only have 8 ...
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0answers
99 views

Slow query with ORDER BY with index created (more than 4mins on 0.6million records

I ran into a very weird query performance situation. If I run this query without order by, it finish in millsecs, with order by, it ends up with more than 4mins. EXPLAIN SELECT `book_book`.`id`, ...
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0answers
253 views

Is it possible to optimize a range query so an explain statement would state “using index” instead of “using index condition”?

I have a very large table where specific queries made by my application are timing out. The table looks something like this: LargeTable ------------ Id [BIGINT(20)] UtcTimestamp [BIGINT(20)] Pivot ...
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0answers
201 views

How to increase MySQL performance with joins

I have a MySQL database with InnoDB engine. Particularly one of my queries became very slow. The query is shown below: SELECT t1.`ARTREF1` FROM `lijnen` AS t3 INNER JOIN (`kortingen` AS t2, ...
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42 views

Is it better performance wise to check if a field needs update if you know the record does

In the queries we use all the records in one table that has data which needs to be placed in a another system had a Insert, Update and Delete flags (i, u, d being 1 in the record), this way we can ...
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0answers
59 views

designing mysql for large tables

Currently I've been assigned the task to research ways to speed up an existing project. It's going to be rebuild so we can start from scratch, the current implementation has been build by another ...
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0answers
53 views

Postgresql function taking long time on newly restored database

I have developed one function in my PostgreSQL database. It was taking 12-15 seconds to execute. Now I have restored a new PostgreSQL 9.0 dump using following command: pg_restore -hx.x.x.x -p5432 -d ...
0
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0answers
43 views

Creating a dedicated HD parition at beginning of disk for data files, benefits and draw backs?

I am thinking of creating a dedicated partition on the harddisk for the mysql database data files in /var/lib/mysql , while considering those 2 points: a dedicated partition will avoid any file ...
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0answers
73 views

Query take a long time! Is that server issue?

When Query runs on Server (shared-server) it takes (2.5332 sec) But when I run the same Query on another Server (dedicated-server), it takes only (0.0205 sec). I don't know where is the issue! Is ...
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0answers
95 views

MySql Scalability, Master Slave replication a good idea? Read description please

I have a database on mysql which is scaling on daily basis and right now its on 5M records and in a month it may double itself. I have a table containing users data which is the largest one. I have ...
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579 views

Using something better than UNION for combining multiple queries

I have one big query which is based on 12 smaller queries that I have put together using UNION. A relative simple example of my query: (SELECT 'type1' AS 'type', fieldOne AS someField, ...
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288 views

Temporarly disable cache in oracle 11g

I want to disable the caching for my session in oracle 11g to see how long a query takes. Is this possible or is there a better way for meassuring the time a query takes to run?
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58 views

Database too slow after CHARSET Conversion

I have an Oracle database which runs on version 9.0.1 with WE8859P1 charset and i'm trying to migrate it to the version 9.2i which has the WE8MSWIN1252 charset. The conversion is made without any ...
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0answers
599 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 ...
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135 views

Please help configure my Mysql for 12GB 4cores server

I use a dedicated server with 12GB memory and 4 core CPU with Ubuntu 12.04 LTS (x64). This not just a database server. MySQL appears to be restarting frequently, I think I can tune the config to ...
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0answers
71 views

Long disk queue when no traffic

I got dedicated disk (RAID 10 - 4 SAS disks) for Postgres. I am bit worried as recently, I see under Windows Resource Manager disk queues like 3+ in the mornings (low traffic hours), like every 30-60 ...