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
0answers
3 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 ...
0
votes
1answer
14 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 ...
0
votes
0answers
20 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
84 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 ...
2
votes
4answers
239 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 ...
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 ...
3
votes
1answer
80 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 ...
0
votes
1answer
35 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 ...
1
vote
3answers
161 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
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"? ...
0
votes
0answers
21 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 ...
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 ...
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 ...
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 ...
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
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
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 ...
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 ...
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, ...
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 ...
0
votes
1answer
45 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 ...
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 ...
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 ...
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,
...
0
votes
1answer
45 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 ...
0
votes
0answers
39 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 ...
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 ...
4
votes
1answer
133 views
Optimum configuration for 4 SSD drives
I would like to move a SQL Server database from a shared configuration with the web-server to it's own dedicated box. My current budget will allow me to put 4 disks together in an array with a single ...
1
vote
1answer
77 views
Database hangs randomly
My database works fine but suddenly it stops responding to queries and I get only timeout errors on my website then after about 10-30 minutues it starts responding again on it's own but queries take ...
8
votes
2answers
271 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 ...
0
votes
1answer
37 views
Will Partitions and Indexes on the same table help in performace of Inserts and Selects?
I have a table containing the list of visitors and this table has the following information.
Visitor Browser Information
Visitor Location Information
Visitor Time Information
No of Visits
I have a ...
2
votes
1answer
22 views
Debugging SSAS Timeouts
I have a drill-through problem apparently related to security. Users in one role are seeing timeout failures when trying to invoke a drill-through action. They have permission on the action through ...
3
votes
3answers
324 views
Are individual queries faster than joins?
Conceptual question: Are individual queries faster than joins, or: Should I try to squeeze every info I want on the client side into one SELECT statement or just use as many as seems convenient?
...
-1
votes
4answers
83 views
Dropping and recreating indexes [closed]
I most often come in a situation where the users move there database from one server to another and immediately after they move they face performance problems(slowness).
I somehow manage to rebuild ...
-1
votes
1answer
43 views
Performance issues with query of many joins on MySQL server [closed]
We have serious performance issues with a query joining a lookup table (stores key values pairs) around 20 times. The lookup table contains around 100.000 entries.
SELECT DISTINCT
...
5
votes
1answer
106 views
Troubleshooting SOS_SCHEDULER_YIELD wait
Running our corporate ERP (Dynamics AX 2012), I noticed our production environment seemed much slower than our development systems.
After performing the same activities in both the development and ...
2
votes
2answers
61 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: ...
0
votes
1answer
20 views
Separate table by often changed / not often changed data?
I have a application which querys different gameservers, and stores for example if the server is online, and how many players are connected. But of course there is also data which is changed rarely.
...
0
votes
0answers
55 views
How to improve the performance for SQL Server Count(distinct()) and Sum() functions? [closed]
The below one is my query. It's taking 12 seconds for the execution process. The count(distinct()) and SUM() functions are taking long time for execution. I tried it after create the non-cluster index ...
0
votes
1answer
49 views
Do certain string patterns affect query performance on a VARCHAR column?
I am a beginner on MySQL Administration and performance problems. Now this is confusing me.
I have a VARCHAR column identity, the string in it is consisted of a Class type and an id, like note:123, ...
7
votes
4answers
620 views
Index Seek vs Index Scan
Looking at an execution plan of a slow running query and I noticed that some of the nodes are index seek and some of them are index scan.
What is the difference between and index seek and an index ...
5
votes
1answer
58 views
Sudden increase in log_file_sync waits
I'm on Oracle 11gR2 with a 2 node RAC system. It's shared fiber storage to an EMC Clariion.
Last friday things went bad..fast. All of the sudden processes that normally ran fine for years became ...
1
vote
0answers
35 views
Performance of database with transactional data
There are lots of row modifications (several thousands of rows per minute) in our PostgreSQL database that stores transactional data. We have a problem because PostgreSQL runs vacuuming process and ...
1
vote
1answer
25 views
How un-clustered is a CLUSTER USING table
I have some tables which benefit greatly from CLUSTER ON/CLUSTER USING in Postgres. Data accessed at the same time is "defragmented" into a small number of disk blocks:
# CLUSTER table USING ...
1
vote
0answers
69 views
Performance Hit when upgrading to Oracle 11gr2
I am experiencing the same symptoms as noted in this question which was closed and does not have a satisfactory answer.
Original Question
We've recently upgraded from Oracle 10gR2 (10.2.0.4 ) to ...
0
votes
1answer
51 views
When is it worth it to use Triggers and stored procedures/functions? [closed]
As an example, lets say I have a forum application and for every topic that is created, I have a trigger that fires a database function creating a post.(lets assume we have a topics table and a post ...
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
71 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 ...
