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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Sql server full text search performance with additional conditions

We have a performance problem with SQL Server (2008 R2) Full text search. When we have additional where conditions to full-text search condition, it gets too slow. Here is my simplified query: ...
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1answer
587 views

Will certain Database Compatibility cause performance degradation?

I'm running a variety of SQL Servers from 2005 to 2012 across several machines. I have many of these databases running in SQL Server 2000 compatibility mode. Will using an older compatibility in a ...
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2answers
257 views

Performance effect of indexing foreign keys

My database is for an HR application with performance reviews and I am interested in whether I should index my foreign key. There are two tables involved. The first is a ratings table with 2 columns: ...
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1answer
167 views

excessive CPU utilization by SQL server

I have an issue with SQL server 2000. Its CPU utilization is high from 9.00 AM to 5.00 PM. Three applications use this server through three different instances but when the CPU utilization is high one ...
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1answer
221 views

Log all than queries taking more than X seconds

I have a database Microsoft SQL Server 2008r2. I have some applications in different programming languages. I would like to log all the queries that take more than X seconds. I guess that the I ...
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3answers
255 views

How can I identify and fix bottlenecks in an Oracle11gR2 import

I've recently been tasked with moving our Oracle 11g database from a linux CentOS desktop to a windows 2008 server. Given I've not done much behind the scenes stuff with oracle before I'm a bit out of ...
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2answers
798 views

Closed loops in database model, does it affect the performance?

I have heard that having loops in the database relational model should be avoided. From what I can think of, it is not a good practice, because there will be more than one different pathes to get the ...
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1answer
3k views

Why Is oracle ignoring my index?

This query is not too complex: select trunc(created_date, 'MONTH') as created_date, al.op_name, al.region, al.alarm_type, COUNT(1) as total_new, SUM( (SELECT ...
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Querying a database efficiently for a huge chunk of data

Here is my query SELECT * FROM ( SELECT a.*, rownum rnum FROM ( SELECT id, data FROM t ORDER BY id ) a ...
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1answer
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Prevent a single query from hogging all resources

I have a production database server running SQL Server 2008 R2. How can I keep a user query on one database from hogging all the system resources and bogging down all the databases on the server? The ...
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1answer
1k views

Performance Inserting and Updating Millions of rows into a table

We have a CSV the user imports into the Application. After inspecting the CSV, validating and applying some business logic, we got Inserts and Updates operations we should perform into a ...
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1answer
1k views

Postgres multiple joins slow query, how to store default child record

Ive got a small database in Postgres, about 10,000 records storing company customers. I have a "slow" performing query (about half a second) which is performed very frequently, and my boss wants me to ...
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1answer
206 views

SQL from/where or join?

I was wondering performance wise what would be faster a join or a from and where query. I am trying merge and update query but performance is terrible?
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1answer
444 views

Pros and Cons of having additional columns in join table of many to many relationship

I searched but did not find any discussions on this topic. Are there any pros and cons on creating many extra columns on joined table? Does it affect speed of data retrieval because we are joining 3 ...
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2answers
252 views

Improving the performance of a long query

I have a query that i have let run for a few hours. I am forced to kill the query because it is taking up 60% of the CPU. Is there anything i can do to improve its performance? select ...
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2answers
1k views

SQL 2005- stored procedure performance troubleshooting

I am investigating performance issues for a stored procedure on SQL 2005 server. This is how I intend to do it: Analyze the stored procedure for any bad TSQL practices (like count * etc) Run it ...
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2answers
521 views

Degrading PostgreSQL 8.4 write performance

Load testing of postgresql 8.4 for OLTP application suitability resulted in unpleasant situation when throughput of the database significantly degraded over time from thousands of write transactions ...
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2answers
704 views

SQL datatype choice for flagging a read/ unread message?

I have a table where I want to track Boolean type operations. in addition, a business requirement is that I know the date of the action and not just the Boolean value. for example if a message is ...
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1answer
98 views

Optimise huge Postgres table for fast read

I'm about to create a Postgres table with 1.5 billion rows. The table will just have a single TEXT column. The table is effectively a blacklist. When a user of my software saves certain data, this ...
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2answers
121 views

Is it possible for increasing the SQL Server max memory limit to degrade performance?

As far as I can tell, raising the SQL Server max memory limit has no drawbacks, provided that sufficient memory is left for the OS and other applications. Assuming this is the case, can there be any ...
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1answer
191 views

Can you put a SQL DB on a NAS? [closed]

Can you put a SQL DB on a NAS drive? For example can I put the PostgreSQL DB "files" on a Sinology NAS or am I better to leave everything on a "real" PC? (like, say, a regular PC server running Linux) ...
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2answers
151 views

Overhead of decomposing complex query into multiple simple queries?

What kind of overhead should I expect when replacing a single complex query with multiple simple queries? My goal is to improve the readability and portability of all SQL code so I will be favoring ...
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2answers
155 views

Should I drop a foreign key if I use a soft delete?

"ON UPDATE" scenario never happens in my application. As soft delete is used, "ON DELETE" cascade and restrict scenario never happen as well now. Then, should I just drop foreign key because I have ...
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2answers
960 views

Ideal values for wait time in SQL server

This is related to my own post here The SQL server starts everyday at 8:30 AM and stops around 9:30 PM.( So wait times will reset everyday) SQL server will be used by around 60 users ...
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1answer
385 views

MySQL with high CPU and memory usage

here we have a VPS with 3.2GHz quadcore processor with 2GB of RAM and 4GB of SWAP which need to work with a high intensive legacy system (read: bad coded). The main problem is that the CPU (~80 - ...
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1answer
658 views

Performance issue with TOP (1) on a nullable column

I need help to identify the reason for a performance issue. Actually following query sits in a scalar-valued-function but that is not the reason for the issue since it needs the same time as query: ...
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1answer
65 views

Can SQL Server WebAdmin degrade the performance of my site?

Once upon a time a had to use the Parallels WebAdmin interface. After contacting the support team that hosts my website and informing them that I must use the Webadmin, they informed me that: MS ...
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2answers
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Does using LIMIT improve the performance and is it noticeable?

I want to understand the following. Assume that I have a complicated query with let's say a join of 5 tables a group by summations and order by. Letting aside any optimizations to the query itself ...
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2answers
4k views

MySQL not using indexes when joining against another table

I have two tables, the first table contains all articles / blog posts within a CMS. Some of these articles may also appear in a magazine, in which case they have a foreign key relationship with ...
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1answer
4k views

Why is my Amazon RDS instance so slow?

I currently run a Windows Server with SQL Server Express. I'd like follow best practice and separate the application from the database, so I've created an RDS instance and exported my database. ...
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1answer
656 views

SQL Server manage indexes

Is it possible to automate the managing of indexes on my database? I'm looking to see if there are any scripts or programs that can automate this process. Would it be possible to use stats generated ...
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2answers
5k views

Why does MySQL (InnoDB) table get faster after OPTIMIZE TABLE, but then don't work?

I have a Django web application that stores data in a MySQL InnoDB database. There is a particular page that is accessed a lot on the django admin, and the query is taking a long time (~20 seconds). ...
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1answer
3k views

MySQL / InnoDB: Does daily optimization improve performance?

Would performing daily optimizations of tables increase performance for MySQL and InnoDB? I have never did this before, but I have seen this module for Drupal http://drupal.org/project/db_maintenance, ...
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2answers
276 views

Writing to a DKNF database, but reading from a de-normalized table for performance?

Would the following approach be reasonable? The Goal: queries have to be relatively fast, but without the hassles incurred by writing to a de-normalized database. The Context: A database for ...
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2answers
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Improving performance of nasty nested-view joins

I have a moderate-sized database spread out over a few tables, the rough architecture is: Input Data (Data ID, Session ID and a few fields of statistical importance) Input File (Data ID and a blob) ...
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2answers
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How to sync two MySQL high load tables with 10M rows?

I have two identical MySQL innodb table with 10M rows each. One is used at backend while other at application end. Thus, either of them loaded. I need to synchronize them in a way which is fast and ...
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1answer
363 views

Oracle ash report

Recently, i have been handed over with an ash report from DBA. To me this report is like french. I have no idea what it is about and what all is written in this report. Can someone please guide me in ...
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2answers
733 views

How to compare performances of two databases

There are two database servers and I want to compare their performances. Both have Windows operating system and and Oracle (10.2.0.4 and 11.0.2) database. Both are OLAP databases with 15-20 users ...
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2answers
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Mysql consumes a lot of memory

Here is my situation. I have an ubuntu server monitored by nagios. recently nagios sends alarms regarding the memory consumption on the server. I logged into the server and executed the top command ...
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2answers
402 views

Slow SSD on Dell 710

We recently upgraded our Dell T110 server to a Dell T710 with a 100GB SSD drive. We were hoping that we would see a tremendous improvement in mysql select performance, but unfortunately the new ...
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2answers
319 views

Differences between development and live database setups

I was wondering if there are any best practice recommendations on setting up databases in a dev environment versus a live environment with regards to configuration. Should they be as similar as ...
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1answer
54 views

Which database technologies to consider for a data search application?

I'm designing an application that only does read queries to some database tables (it's a kind of search application); the queried data is updated at night by the system (so speed is less critical, ...
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1answer
1k views

Finding reason behind high write IOPS on MySQL (RDS) server

I am having performance issues with an AWS RDS instance (running MySQL 5.6). This is the backend db to an XMPP server called Tigase. According to Tigase Inc. this type of db instance should be able ...
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2answers
101 views

Why is this simple join taking so long?

I'm trying to run some reporting queries on a MySQL database, and I'm running into serious performance issues for some reason. One table, page_views, is extremely large (~70 million records), so some ...
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1answer
303 views

Character varying index overhead & length limit

I have a unique constraint on a character varying column that will mostly have lengths of approximately 600 but could get to 10 million. I have read about B-Trees, but I can't determine how much disk ...
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1answer
100 views

Will adding more indexes speed up using RedGate SQL DATA compare?

We want to use RedGate's SQL Data Compare to migrate user data from one DB to a DB on a completely different provider. This will be a time-sensitive operation as we do not want our site offline for ...
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2answers
196 views

SQL Server 2008 R2 Missing Index

I am performing index maintenance on a database. I have run SQL script that uses DMVs to provides a list of indexes SQL Server believes should be created. I am not creating indexes just because the ...
2
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1answer
113 views

Avoiding Deadlocks

We currently have a trigger-based system in place that does the following: When records in certain tables are modified, a trigger fires that makes a field NULL in a varying number of records in ...
2
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1answer
309 views

Specifying columns in LEFT JOIN through subquery beneficial performance wise?

I'm trying to understand how JOINS are handled, and was wondering about the following: Imagine a big query concerning a lot of tables, I'm really looking for small optimizations as it's a pretty ...
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2answers
290 views

Autogrowth, shrink and database performance

I have already asked some questions about Autogrowth and shrink. But I have some doubts related to it. 1)I have a database which grows about 300 MB every month. So is it best to set Autogrowth of 300 ...