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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51 views

SQL Server Perfmon % Processor Time unbalanced

I am somewhat of an accidental DBA, and I'm troubleshooting a SQL Server box where performance has been notoriously poor (as reported by the customer). I was not involved in the initial planning of ...
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26 views

Mysql table with only two columns, nothing unique: Will an index increase search performance?

If my table only has two columns (username, groupname) and a million or so rows, will an index improve performance at all? Wouldn't it take just as long to search the index file as it would to search ...
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17 views

MySQL 5.5, Xubuntu 14.04 - INSERT and UPDATE bottleneck

DBAs: I have been developing and maintaining plugins for Moodle for the last ~2 years, and have recently decided to try using my local desktop again, rather than my institutions ESX VMs, as a ...
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6 views

Sysadmin tools for SQLAnywhere

I'm seeing a performance issue in a 3rd party application based on SQLAnywhere 7. The DB engine seems to be dramatically underperforming on the hardware provided. It seems to have a upper limit on the ...
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5 views

Page cache installation in magento admin panel

Hi just added pagecache from varnish in Magento through the magento connect. It went in ok, just wanted to know, the correct configuration. In magento admin panel for the correct set up in the page ...
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24 views

Performance: Interleaving several statement handles in MySQL

Does interleaving several statement handles slow the system down? Example (Perl): $sth1->execute(...); $sth2->execute(...); $sth1->execute(...); $sth2->execute(...); (interleaved) vs ...
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13 views

Excesive use of RAM on MysqlServer

The RAM of a server where I have installed mysql is always 100% and looking at the processes that are running, MySQL is the most consumer on CPU and memory and I can see the cause of great use RAM.   ...
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54 views

Performance issue in Postgresql9.3

I have very good configuration server dedicated only for PostgresSql. Server is 16 Core 122 GB RAM on Linux machine. select version(); **PostgreSQL 9.3.4 on x86_64-unknown-linux-gnu, compiled by gcc ...
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16 views

View in View slower to execute?

Sometimes it's easier and clearer arranged to create a View from another View. Can this cause some speed losses in relation to selecting everything just in one Big and long View-Command?
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9 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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19 views

Approaching multiple values in same column

I'm developing an Android-application that scrapes the schedule for my university and presents it nicely since the current system is a nightmare. I'm processing a lot of data and it gets down to ...
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28 views

Oracle 9i Low performance on Windows Server Enterprise 2003

I'm facing some problems with performance with my Oracle database running on a virtual machine with Microsoft Windows Server Enterprise 2003 with 8GB RAM. It works pretty well after the database is ...
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51 views

MySQL: after query optimization the CPU is still over 100%

my first time here! First of all I want to say that I'm not a DBA and I have a very little experience with MySQL but I like to study and understand what I'm doing. I have a virtual machine (2gb RAM, ...
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17 views

Oracle after insert trigger vs update performance in plsql block

I want to know whether an after insert trigger is better than an insertion statement followed by update statement in plsql block.
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42 views

SLEEP_TASK and PAGELATCH_XX peaking after upgrade to R2 SP1

I wanted to just add a comment to this question: SLEEP_TASK Wait Type in SQL Server - What does it indicate? But I'm having not only SLEEP_TASK wait but also PAGELATCH_SH and PAGELATCH_EX wait types. ...
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18 views

How can I determine the performance (rows/second) for a certain query on one of my tables?

I want to find the performance (rows/second) for an UPDATE query on one of my tables so I can adjust my WHERE clause to select an appropriate number of records. The table has around 10 million rows. ...
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33 views

more queries vs storing results in database

Environment: Embedded (smartphones) Data Structures: Object Table A: id, field1, field2... Object Table B: id, field1, field2... Object Table C: id, field1, ... , Object A, Object B ... many ...
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55 views

Adding additional condition significantly degrades performance

Have the following query: SELECT * FROM table_A INNER JOIN table_B ON /* conditions */ INNER JOIN table_C ON /* conditions */ INNER JOIN table_D ON /* conditions */ WHERE table_B.state = 'active' ...
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92 views

Are mongodb bulk inserts really increase server perfomance (and faster)?

Bulk inserts always are faster in client side because of saving round-trips, but at the server-side is there any sensible performance improve? It seems the code for bulk inserts, just loops over ...
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60 views

Best design of mongo replica set for DB read/write speed

I'm building a Node app that uses MongoDB. Whilst it would probably be fine to have node and mongo sitting on the same VPS, I want to ensure that the MongoDB is backed up and maintain high ...
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25 views

Performance : MySQL replication or only one big server?

I'm searching about the best choice. We have to host a website with 10.000 - 20.000 visitors per day actually, growing. At the beginning, which would be the best : Having 2 MySQL servers (12 GB ...
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38 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. ...
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44 views

Efficient way to fetch/update X records in a loop

What I need is a simple process that handles requests. I have setup a simple table as follows: CREATE TABLE Requests ( id INT NOT NULL AUTO_INCREMENT PRIMARY KEY, request_param VARCHAR(250) ...
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31 views

Sql Server Standard VS Enterprise

I have been bench-marking SQL Server Enterprise and Standard, Enterprise is using Partitioning by month on the table. The table only has 3 fields, Date-time (DateTimeOffeset(3)), Value (integer in the ...
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31 views

How can the performance of a query that has a condition on two fields of each row be improved?

I have an images table with approximately 5 million rows in it. For the purposes of this question lets say the table looks like this: CREATE TABLE `images` ( `id` int(11) NOT NULL AUTO_INCREMENT, ...
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127 views

index usages on table with recursive relationship

we are working on a project that uses jpa and oracle. In this project we have a table with a recursive relation: Create table alarm ( id varchar2(200), ... alarmcode varchar2(50), parent_id ...
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90 views

Performance measurement in PostgreSQL

When developing server-side stored procedures performance measurement is an important issue. EXPLAIN ANALYZE is very usefull, but when it comes to simple queries like SELECT name FROM clients WHERE ...
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62 views

Explain difference between insert as select and select

Can someone explain why there is plan difference? Same query, same time the explain plan taken. I understand what happen (different order of getting the data) and how to fix it(move to forall insert ...
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72 views

Mysql profiler different duration information_schema.profiling

Hi! I have a problem and no idea how to resolve it. I'm trying to use mysql profiler. I'm using the command: set profiling=1; to turn it on. Later, i execute my query which is correlated ...
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39 views

query comes in slow query when log_queries_not_using_indexes is enabled

This query comes in slow query log when log_queries_not_using_indexes is enabled. SELECT a.id, d.id AS city_id, d.city FROM booking a, sub_area_master b, area_master c, city_master d WHERE ...
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50 views

H2 database binary file full of @^@^@^@^

I am investigating H2 database performance and was curious to why the database file was several megabytes long when only storing hundreds kilos of text, I therefore opened the database file with vim ...
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46 views

Slow exporting SAP Data Services to MySQL (Oracle is faster)

We've a MySQL 5.1 server and we are trying to import data from SAP Data Services from another server. It works but it takes 3h! We tried to setup an Oracle XE server to test the same operation and it ...
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43 views

How to optimize subselect join on large tables

There exists a need to migrate from one definition of a column to the next, so a backfill must occur. In order to get a grasp for the task at hand, I needed some background on the data being updated. ...
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87 views

Mysql View Performance on Aggregate Functions

I've a table that contains weekly statistical infos. ex. Society - Week - Year - Data AAA Inc - 1 - 2014 - 10250 AAA Inc - 2 - 2014 - 5235 BBB Inc - 2 - 2014 - 3210 ... Over this table i need to ...
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70 views

Order before Group

I have this query: SELECT HOTEL.hotelname AS NAME, HOTEL.`boardbasis` AS board, HOTEL.`engine`, HOTEL.`itemcode`, Group_concat(Round(((hotel.cheapestprice / 2) + ...
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57 views

Performance difference search on INT or TEXT in SQLite 3

I'm a little bit confused about SQLite 3 type system. SQLite 2 was typeless with only exception of INTEGER PRIMARY KEY. I don't get if SQLite 3 are same or not.. I have in my table PRIMARY KEY of INT ...
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100 views

MySQL Load Avg High — CPU bound or IO Bound or Memory Issues

We are using MySQL 5.5 and the database is approximately 10TB. The load avg is constantly high during day time. Following are the configurations and a snap shot of a 'top' command. I wanted ...
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26 views

MySQL cluster with RAID0

I use several EC2 (M1.LARGE) instances with ephemeral storage. Would RAID0 improve write and read performance? I'am only interested in performance. Has someone experience? Is the speedup=2??
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35 views

Why does a scrambled junction table destroy the speed of my query?

I have two schema in a MySQL database, one containing raw data in MyISAM tables and the other containing the results of some processing tasks performed on the raw data, also in MyISAM tables. For ...
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28 views

MySQL: system variables and status variables related with Disk I/O

How disk I/O is related with MySQL performance improvement. I have a MySQL-5.1.58 based Intranet application equipped with Windows 2008 server and 8 GB RAM. Even, When my application face performance ...
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70 views

MySQL cluster performance very poor on Amazon

We have currently a project running where we need to store 1 to 20,30 million 500B to 2kB records. We need to use MySQL cluster on 4 EC2 instances (8GB Ram, 2 cores) and ephemeral storage (Records ...
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135 views

MySQl: slow query is not using index in joining

Below is the configuration of my DB server: Apache version : Apache/2.2.22 (Win32) mod_ssl/2.2.22 OpenSSL/0.9.8 PHP version : 5.3.13 MySQL version : mysqlnd 5.1.11 Windows Server 2008 Standard ...
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136 views

how I can set tmp_table_size for 16GB long table?

I am posting the same question as I posted in SO, but somebody advice me to post it here. I have a 16GB big table with 8 partition. And RAM 4 GB. I am running a query - SELECT ...
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92 views

Postgres chooses a bad query plan

The following query finishes in 1.5s (which is ok, the table contains about 500M rows): explain (analyze, buffers) select sales.* from sales join product on (product.id = sales.productid) join date ...
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42 views

Recommended plan for 0min RTO and RPO

I have a Windows Server 2008R2 Server, running SQL Server 2008R2 SP2. The server currently only does a full backup once daily. The server's operational hours are between 8am and 5pm. The server's new ...
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44 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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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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128 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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308 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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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 ...