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.
0
votes
2answers
50 views
How to modify MySQL 5.5 settings that were set during the installation?
Especially the one that defines how MySQL is gonna use server's CPU. I'd like to boost performance. Also, what are other ways to boost MySQL performance? (Maybe some code optimization hints?) Anyway. ...
0
votes
2answers
30 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
1answer
275 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: ...
1
vote
1answer
20 views
Will certain Database Compatibility cause performance degradation?
I'm running a variety of MSSQL Servers from 2005 to 2012 across several servers.
I have many of these databases running in MSSQL 2000 compatibility.
Will using an older compatibility in a newer ...
0
votes
1answer
18 views
What is wrong with table_cache hit rate?
In my.cnf I have:
table_cache = 524288
open_files_limit = 65535
Both are at max allowed value for mysql config. Both are less than max open file limit:
# cat ...
3
votes
1answer
81 views
Insert performance with Geography column
I've been tasked with inserting data into a SQL Server table with a geography column. I've found that my times for doing inserts (same data 1.5 million rows) go up increasingly.
I started out with no ...
1
vote
1answer
91 views
Why does that query cause lock wait timeouts?
From time to time, I find a lot of these errors in my PHP error log:
MYSQL.1213: Deadlock found when trying to get lock; try restarting transactionSQL
The problem persists for about 2 or 3 minutes. ...
0
votes
0answers
22 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 ...
6
votes
2answers
85 views
What can I add to a server to make SQL restores faster?
I have a 2.8TB SQL database (mostly data files, some 400GB of log files) that currently takes around 9 hours to restore. This database is used for testing purposes and must be deleted and restored ...
0
votes
1answer
56 views
How to keep an Oracle 11g instance lean?
As a Mac user I run a local Oracle Enterprise Linux (OEL) Developer Day VM that houses an Oracle 11g instance for development/unit testing. I frequently refresh the data in the schemas (sometimes ...
1
vote
1answer
44 views
Why InnoDB ALTER TABLE is so slow? [closed]
The machine has a 4-core hyper-threaded Intel i7 670 @ 2.8GHz, 16G RAM, 8G of which is InnoDB buffer pool. The database resides on Intel SSD disk. DBMS is MariaDB 5.5.30 x64 running under Windows ...
1
vote
0answers
115 views
sql server 2008 execution plan different on two production servers [closed]
We have two servers running SQL server 2008 R2, with identical databases, where we implemented a datawarehousing solution. The cube processing operation was taking a VERY long time in one of the ...
2
votes
4answers
245 views
High CPU usage on SQL server - Slow queries [closed]
Our MS SQL Server is using about 95% of the CPU-power.
After a server (hardware) restart, or a SQL-Service restart, the usage is 0% and slowly increases over the course of 1-3 days. Depending on how ...
8
votes
2answers
272 views
More CPU cores vs faster disks
I'm part of a small company so as usual covering a number of different roles. The latest of which is procuring a dedicated SQL Server box for our .NET web app. We've been quoted on a dual Xeon E5-2620 ...
2
votes
2answers
257 views
SELECTing multiple columns through a subquery
I am trying to SELECT 2 columns from the subquery in the following query, but unable to do so. Tried creating alias table, but still couldn't get them.
SELECT DISTINCT petid, userid,
(SELECT ...
3
votes
0answers
29 views
High CPU usage on SQL server - Slow queries [duplicate]
Our MS SQL Server is using about 95% of the CPU-power.
After a server (hardware) restart, or a SQL-Service restart, the usage is 0% and slowly increases over the course of 1-3 days. Depending on how ...
0
votes
2answers
101 views
How do I use subquery on the same table in MySQL?
I have a query like this which takes a really long time to run. The table is around 4 million rows.
DELETE FROM TABLE WHERE value_was IS NULL OR value_was <= value_now;
I'm hoping I could ...
0
votes
1answer
36 views
Can we create a table in specific datafile - Oracle 11g R2?
I am buying a new server than has two HDs:
300 GB with 15000 rpm.
600 GB with 10000 rpm.
I am thinking to allocate the datafiles in both hard disks. and put the less used tables in the data files ...
0
votes
1answer
47 views
Having too many connection problem
We have an magento store and having 9K products and 2 store views the trouble is we are getting too many conection error while the site is in normal loads.
1) We have 100 connectoin open in mysql.
2) ...
7
votes
2answers
3k views
When To Update Statistics?
I've inherited a Maintenance Plans that does the following:
Cleanup old data
Checks DB integrity
Performs Database and Transaction Log Backups
Reorganizes Our indexes
Updates Statistics
Delete old ...
1
vote
3answers
162 views
Will performance be better if I specify a filter multiple times?
Do I gain more performance if I repeat the filter in the WHERE clause on both sides of an OUTER JOIN?
To clarify using code:
select *
from #main_select
left outer join
(
select
main_id
...
0
votes
0answers
27 views
Firebird database performance after server upgrade/restart
Got a 350 GB database (more than 40M records plus 0 - 1000 BLOBs for each record in another table). After upgrading Firebird to version 2.1.5 (mainly because of filesystem cache issue) database became ...
0
votes
0answers
25 views
Which database and which database model for commenting system?
I am working on some commenting system and I have some doubts. Firstly, my question is which model would perform faster for "find conversation and show it and its comments with specific attributes"? ...
1
vote
1answer
51 views
Most efficient way to sort data fields into SQL
I'm trying to decide on the most efficient way to sort various data values. Here's how the data arrives:
Device X sends a text string "name=value&name2=value&name=value"
On arrival that ...
1
vote
2answers
436 views
Mysql innoDB write operations are extremely slow
I'm having serious performance problems with MySQL and the InnoDB engine. Even the simplest table makes writing operations (creating the table, inserting, updating and deleting) horribly slow, as you ...
0
votes
0answers
22 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 ...
4
votes
4answers
102 views
In Memory Database for high transaction and volume spikes on a website [closed]
I am looking at the IA for a hypothetical application scenario, for example:
A high demand application such as an online ticketing website where there can be demand for 100,000 tickets to be ...
1
vote
1answer
107 views
Deriving formulas for input/output
I'm currently enrolled in a DBS class and am having problem with an assignment. I've searched around and have been unable to understand what it is I'm meant to be doing with this derivation formula.
...
0
votes
0answers
12 views
FTP map disapears after a while [migrated]
I'm deploying an C# mvc application with a couple of content maps to save my images in. I made them all in the ~Content/Images/ map and they work fine but after a while, sometimes just 15 minutes, a ...
2
votes
1answer
410 views
MySQL performance tuning + queries stuck on “Copying to tmp table”
The latter part of the question's title (queries stuck on "Copying to tmp table") has been addressed many times, and I have spent a fair amount of time researching this. I would appreciate it if you ...
0
votes
1answer
46 views
MySQL+Web-App Performance Issues using different servers
We are having a performance issue with our MySQL servers that does not make any sense. I have read countless articles from many people (mostly Percona) and have made my.cnf tweaks. We have even manage ...
3
votes
2answers
67 views
If I update a column record in a table, will indexes that do NOT have this column in it be affected?
In terms of performance if I have a table like so:
CREATE TABLE [TESTDATA].[TableA](
[Col1] [nchar](5) NOT NULL,
[Col2] [nchar](2) NULL,
[Col3] [float] NULL
CONSTRAINT [TableA_PK] PRIMARY ...
0
votes
1answer
65 views
Am I wrong in table design or wrong in selected index when made the table?
I've build web application as a tool to eliminate unnecessary data in peoples table, this application mainly to filter all data of peoples who valid to get an election rights. At first, it wasn't a ...
0
votes
2answers
75 views
Multiple database servers for performance vs failover
If I have two database servers, and I am looking for maximum performance vs high-availability, what configuration would be best?
Assuming the architecture is two load-balanced web/app servers in ...
0
votes
0answers
17 views
MySQL innodb monitor and insert/update operation
There is only one table in MySQL that has two columns like id(int) and data(blob) And, the problem I've faced is that it looks like there's something wrong with insert/update operations. For some ...
1
vote
1answer
104 views
Mysql DB server hits 400% CPU
I have been facing problem with my database server quite a month, Below are the observations that I see when it hits the top.
- load average 40 to 50
- CPU % - 400%
- idle % - 45%
- wait % - ...
3
votes
2answers
200 views
Configuring PostgreSQL for read performance
Our system write a lots of data (kind of Big Data system). The write performance is good enough for our needs but the read performance is really too slow.
The primary key (constraint) structure is ...
2
votes
1answer
69 views
How to avoid large joins when determining which rows a user is authorized for?
Typical wep app situation: you have logged in users querying for resources exposed through an API. As a hypothetical example, company administrators quering for their employees' time sheets:
company ...
0
votes
4answers
76 views
MySql Order by isnull() Performance Problem
my sql below is use for listing stock added from 10 days ago.
Order by isnull(Price) is use so that stock without any price yet will still being listed.
AddDate and Price has an index.
SELECT Id, ...
3
votes
2answers
903 views
“freeing items” taking forever on inserts, updates and deletes
Recently I migrated all my MySQL database tables from MyISAM engine to InnoDB. I'm using the DotCloud MySQL service as my server (http://docs.dotcloud.com/services/mysql/).
After the migration, ...
4
votes
1answer
47 views
How much data can SQL Server full text indexing handle?
I realize that the question is vague and it depends on hardware and our needs.
We currently have 5 million rows of data, a total of 5GB of data which we want to index using full text indexing. Our ...
2
votes
1answer
46 views
SQL Server full safety mirror commit overhead less then Time to send?
How is it possible that the time to send value is greater then the mirror commit overhead? The mirror operates under full safety so this means that the commit is only done @ principal when the commit ...
0
votes
1answer
46 views
Changing the SGA and/or PGA in Oracle 11g affects the performance of the queries?
I am making a practice for school where one of the questions is if changing the SGA/PGA size would affect the queries performance and in what sense. I have been looking around for how to do that and ...
4
votes
1answer
39 views
Performance impact of sp_configure blocked process threshold change
I've been tasked with identifying any blocking happening on a production server. My plan to achieve this is to use
EXECUTE sp_configure 'blocked process threshold', 5
In combination with a server ...
17
votes
2answers
563 views
Get and Put performance testing on Google BigTables (and other integrated DBs)
What are some effective ways to perform programmatic performance testing on database operations, especially in environments where the databases themselves do not offer dedicated tools?
For example, ...
8
votes
2answers
643 views
In Google App Engine, what is the most effective many-to-many join model?
The BigTable design rejects many of the philosophies of standard relational models, explicitly preferring denormalization to a big host of tiny tables.
One of the larger areas where this is a problem ...
0
votes
0answers
36 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,
...
4
votes
2answers
5k views
way to prevent queries from waiting for table level lock
We've encountered a problem after moving the database of our customer to an extra server. This should have had positive effects on the site's performance, but there is a problem with table locking in ...
6
votes
1answer
76 views
Strange behaviour DBCC Shrinkfile
I am attempting to run a dbcc shrinkfile in chunks of 1GB against a database where 95% of the data has been archived and deleted. I'm leaft with a 235GB file where 9GB is data/indexes. I want to ...
0
votes
0answers
41 views
What's the best database for analysis/research applications, i.e. involving complex queries but few transactions? [closed]
I'd like to start a discussion on what people think what the best database environment (MySQL, MS SQL, PostgreSQL, ...) is for data analysis and research applications like encountered in empirical ...
