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.

learn more… | top users | synonyms

2
votes
1answer
608 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 ...
2
votes
2answers
3k views

Fast XML, slow XML

Our database update Windows application needs to transfer some data between two databases as part of the process for a certain one-time update. I chose XML as the intermediary to move the data. The ...
2
votes
1answer
2k 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, ...
2
votes
2answers
264 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 ...
2
votes
1answer
218 views

Why are my queries getting really slow?

I own a WordPress installation, and Updated to 3.4.1. After the upgrade, I experienced a very strange slow-down. After all, I used the define('SAVEQUERIES', true); in my wp-config.php with ...
2
votes
2answers
2k views

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) ...
2
votes
2answers
2k views

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 ...
2
votes
1answer
298 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 ...
2
votes
2answers
414 views

Performance differences between executing via Linked Server vs. SSMS

We've had an issue reported where a stored procedure was behaving badly when called from some .Net code. On the face of it, that sounds similar to this case, which turned out to be due to EDMX, but in ...
2
votes
2answers
663 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 ...
2
votes
2answers
3k views

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 ...
2
votes
2answers
387 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 ...
2
votes
2answers
289 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 ...
2
votes
1answer
48 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, ...
2
votes
1answer
524 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 ...
2
votes
2answers
91 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 ...
2
votes
1answer
210 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 ...
2
votes
1answer
92 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 ...
2
votes
2answers
154 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
votes
1answer
104 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
votes
1answer
245 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 ...
2
votes
2answers
219 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 ...
2
votes
1answer
176 views

Creating indexes on AutoId and time column

My table structure is as follows Events( AutoId int identity(1,1) //Primay Key, clustered index EventTime datetime // non unique, non clustered index FileName nvarchar(1000) ...
2
votes
1answer
397 views

What database and setup can handle several million inserts per minute? [closed]

We have come to a point where for a few of our customers' systems, at peak times, events are generated at that crazy rate. That is, millions of new events per minute (between 1M and 2M). The ...
2
votes
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. ...
2
votes
2answers
8k views

MySQL using too much CPU

I'm studying to be a DBA right now because I have a massive live database that is very sensitive that I manage. Here's the current system stats of my dedicated database server: CentOS 5.9 24gb Ram 8 ...
2
votes
2answers
1k views

Is there a difference in performance between @date and getdate()?

Usually I use the getdate() function in my where clauses to go back in time. Something like: DOC.DATUM >= DATEADD(DD,-1*SSN_SDO.DANA_ZA_POVRAT,GETDATE()) Will SQL Server 2008R2 perform faster ...
2
votes
2answers
355 views

How to implement posts with “seen by” like facebook?

Inside a Facebook group there is a feature when every time see the group newsfeed it mark all posts as seen by me. And if I see a specific post inside a group thought a url ...
2
votes
1answer
545 views

How should I model a binary-tree like data using Adjacency List?

I'm making a system where a user can recruit others, resulting in a binary tree model of users. I have decided to use Adjacency List to model the data but I have some doubts about the number of fields ...
2
votes
2answers
5k views

exist (select * from my table)

My colleague suggests that Query 1 should run faster than Query 2. If it's true, please anyone explain me the reason. Thanks. Query (1): IF ( SELECT COUNT(UnitTrustCounterId) FROM ...
2
votes
1answer
2k 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 ...
2
votes
1answer
46 views

In real terms, how much effect does a bad fillfactor have on performance?

There's a storm brewing, or maybe I should say firestorm. A customer has recently implemented SQL Server 2012 Always On but that's not the most important bit. A list of fires to be put out has been ...
2
votes
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). ...
2
votes
1answer
78 views

MySQL query took 98 seconds to run but EXPLAIN looks okay

I have a query that took 98 seconds to execute this morning, but I can't recreate the problem now, and the EXPLAIN output isn't giving me any clues. Am I missing something? Here's the SQL: SELECT ...
2
votes
5answers
247 views

How to shard 14 gb of data for archival database?

We have 14 GB worth of CSV's containing product information, with each CSV being all the records for a US state. We now want to store this in a database. There would be ~130 million records. The ...
2
votes
1answer
892 views

Tune postgres 9.1 to speedup deletes

I need to tune my postgres db to speed up delete queries. I cant't optimize my db structure yet, so I'm looking for options available on server level for postgres 9.1. I've seen in older posts the ...
2
votes
1answer
119 views

why/how does the number of matched columns influences the way of excecuting a query

Imagine the following situation: Table A uses MyISAM and contains 4 fields (text) with a combined FULLTEXT-index. FULLTEXT fulltext1 | fulltext2 | fulltext3 | fulltext4 Table B uses InnoDB and ...
2
votes
3answers
1k views

whether a big (but not used) ibdata1 slow anything down

Hi I have an ibdata1 that is around 10 gig. I have gradually migrated to 'file per table' using the innodb_file_per_table=1 option such that there are no big tables in ibdata1 anymore. I recently ...
2
votes
3answers
586 views

Tuning Question

Every so often our box is HAMMERED to a crawl %Wait goes to 40 or 50% and connections grows to 300 or so. i think its due to a query running, but i wanted to see if any of the settigns on the mysql ...
2
votes
1answer
300 views

what does SHOW /*!50000 GLOBAL */ STATUS do ?

What is the difference between SHOW /*!50000 GLOBAL */ STATUS and SHOW GLOBAL STATUS I saw that in few scripts and tuning presentations the first command is being used. Is there a difference, ...
2
votes
1answer
71 views

Single field instead of several fields

There is a relational database with the following Users table User Id Name Age Parents Friends Colleagues ... And there are tables Parents, Friends, Colleauges, etc. Due to specifics of database ...
2
votes
1answer
1k views

SQL Server Replication causing locks on table

we have three MSSQL 2005 servers (database is set to compatibility level 80 for legacy reasons) which we have just set up Transactional Replication w/ Updateable Subscriptions on. Two which are ...
2
votes
2answers
271 views

Dramatic decrease in SQL Azure performance after scaling to new edition

Yesterday, we scaled one of our databases in Azure from the old Business edition to the new Standard one (S2). Since then, it has been behaving rather erratically. We have a relatively simple table ...
2
votes
1answer
57 views

3 minutes to import 327Mo database

We do database import a lot of times per day on a server with those specs : Xeon E5-1620v2 4c/8t @ 3,8Ghz 32 Go DDR3 ECC 1600MHz Hard Drive 2x 3 To SATA3 MariaDB 10.14 with XtraDB Given a 327Mb ...
2
votes
2answers
101 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, ...
2
votes
1answer
152 views

Need help tuning my.cnf file

I need help tuning mysql. Currently it is using a lot of CPU. I dont find any query that last longer than 3 seconds in SHOW PROCESSLIST and there are only around 20-25 running most of the time. Still ...
2
votes
2answers
105 views

Does having many databases affect MySQL performance?

I have huge unused databases in MySQL. Do they affect my MySQL engine performance even if they are unused? Do they consume memory on their own? Thanks
2
votes
1answer
92 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] ...
2
votes
2answers
156 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. ...
2
votes
3answers
575 views

MySQL query extremely slow after server restart

I am managing a very large database for a custom application I wrote to keep track of visitors. The DB server was rebooted for the first time in over a year - not even to install any updates, but ...