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
13 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 ...
3
votes
3answers
101 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
vote
0answers
72 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
0answers
13 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 ...
0
votes
2answers
64 views
Cannot Utilize Maximum CPU and Memory Usage for MySQL
Good day.
I know this may be a duplicate of other questions however I have applied all the suggestions in many of the threads, but I remain with the same problem.
I have a single stored procedure ...
7
votes
4answers
347 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 ...
-1
votes
1answer
30 views
Performance issues with query of many joins on MySQL server
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
...
-1
votes
4answers
68 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 ...
0
votes
2answers
41 views
Is there slowdown inserting into an InnoDB table that has no index set?
I have an old application with lots of InnoDB tables, that have no indexes at all, not even a primary ID or such.
Those tables only contain a few thousand rows.
Would it be faster to INSERT data ...
4
votes
3answers
2k views
Is MariaDB a suitable drop in replacement for MySQL on a standard LAMP stack?
I've been wondering lately what (if any) are the improvements available in MariaDB over 'conventional' MySQL?
I understand that where platform interoperability and/or backwards compatibility may be ...
5
votes
1answer
62 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 ...
0
votes
1answer
37 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, ...
2
votes
2answers
56 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: ...
3
votes
1answer
637 views
Linked tables versus stored procedure performance in MySQL
Suppose I have a sub-form, in datasheet view for multiple records, that gives the user full CRUD control over a particular MySQL table. (The records are filtered by the parent-form).
Option 1 is to ...
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
41 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 ...
2
votes
1answer
149 views
Does MySQL have problems with nested insert like with subqueries in where?
Query 1:
INSERT `personal`.`locations`
SELECT DISTINCT `s`.*
FROM `references` `t`
JOIN `locations` `s` ON `first_id` = `s`.`id`
WHERE
`lat` >= 37.3
AND `lat` <= ...
0
votes
2answers
47 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. ...
2
votes
1answer
264 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: ...
0
votes
1answer
47 views
How should I set up my social network database design?
I am designing a db for a Social Network type website where users enter lot of information varying from family member details, education, employment, personal favorite such as TV, movie, music, food, ...
1
vote
1answer
22 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
1answer
66 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. ...
2
votes
2answers
70 views
Linked Server Risks
I'm implementing a new feature which requires data from databases on multiple servers. I just need to union data from all these servers and sort it. The two options that come to mind are:
Use linked ...
5
votes
1answer
53 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
4answers
147 views
Speed up large clustered index creation?
I have a large table, the row count of the table is more than 3 billion, the data space for this table is about 120 GB.
And Intel Xeon CPU E5645 @2.4GHz(2 processors), 24 CPUs, 64G memory, 64bit ...
1
vote
0answers
29 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
2answers
86 views
sql server 2008 execution plan different on two production servers
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 ...
1
vote
0answers
54 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
0answers
102 views
Where and how to store my weird datamart
I could really use some help here.
Here's my situation.
I'm building a datamart in SQL Server 2005, which will furnish a single report (for now). We have 26 clients (medical organizations) that ...
3
votes
2answers
70 views
Load Testing Crash Course
Can someone point me at a good resource to get a crash course in load testing. I have a sql server machine that I need to load test but I havent been thruogh the process before. Also we do not have ...
1
vote
2answers
221 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 ...
2
votes
1answer
65 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 ...
0
votes
2answers
20 views
Partitioning MySQL for “expired” transactions to improve performance
I am dealing with an existing application that uses the database as a sort of transaction log in several cases, for example orders or payments. These tables are large (20 - 60 million rows) and poorly ...
1
vote
3answers
71 views
Improve performance by partitioning
I'm using SQL Server 2012. I’m using CTE to create an orders table from the items table. The final count for the orders table is around 120 million. It is taking about 2 hours for the whole process.
...
0
votes
2answers
60 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 ...
3
votes
3answers
84 views
How can I improve this query?
About a year back I introduced a query which returns a sort of "Customers Also Purchased" data-set. At the time it ran reasonably fast however, as of late it's become very slow, sometimes taking up to ...
0
votes
1answer
34 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) ...
2
votes
1answer
45 views
How to ensure that date-range queries involving multiple time zones are sargable
I am building a web analytics application for search engine traffic only. You can see some screenshots here: http://myhappyanalytics.com/
It works similar to Google Analytics but it only saves and ...
1
vote
1answer
48 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 ...
39
votes
6answers
8k views
How to determine if an Index is required or necessary
I've been running an auto-index tool on our MS SQL database (I modified a script originating from Microsoft that looks at the index statistics tables - Automated Auto Indexing). From the stats, I now ...
1
vote
2answers
356 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 ...
2
votes
6answers
395 views
SQL Server split mdf into multiple files
I have a database called example.mdf with a total size of 1GB which suffers from performance issues. I checked the allocated hardware and it is higher than required, I double checked the design and ...
3
votes
1answer
57 views
How can I get this query to use it's index?
Queries matching this query below shows up in the slow log (with different contentVersionId & modifiedDateTime).
As I don't really know what I'm doing I tried adding indexes to all columns in ...
1
vote
1answer
100 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.
...
2
votes
2answers
103 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 ...
1
vote
1answer
297 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
2answers
190 views
How to tune mysql to be inmemory-like
I've given MySQL 5GB of memory (I use innodb), but when I insert lots of data (dumpfile is 1GB), hard drive I/O is still a bottleneck (CPU is not busy and hard drive is).
Is it possible to force ...
0
votes
2answers
68 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 ...
1
vote
1answer
74 views
Consolidating indexes
I have one big table that is used to generate business intelligence cube. Currently it has around 40M rows and 55 columns. A lot of the cube dimensions are generated by running 'select distinct' on a ...
