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
6 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
...
5
votes
1answer
55 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
45 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
19 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
35 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
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, ...
7
votes
4answers
288 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
52 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
28 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
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
0answers
52 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 ...
1
vote
0answers
60 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
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 ...
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
19 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 ...
0
votes
2answers
58 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
79 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
33 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) ...
3
votes
0answers
99 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 ...
2
votes
1answer
44 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 ...
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, ...
0
votes
0answers
42 views
Hierarchical data best practices
I'm looking for a best practicies\databases to solve our problem:
Currently we are using SQL Server 2008 R2 with HierarchyId. It works ok, but we have a lot of performance penalties due to this ...
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 ...
2
votes
2answers
102 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 ...
0
votes
2answers
183 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 ...
3
votes
1answer
54 views
CPU column 5x higher on one machine vs another?
We're running into a strange issue in a deployed version of our product where the performance is just not very good. When we restore a backup of their DB on one of our machines, it performs as we ...
3
votes
1answer
37 views
Why do psql queries take longer when inserting many rows. Why is it non linear
So if I insert a single row into a postgres database it takes 18 ms. If I do this in a loop like this:
INSERT INTO contacts (numbers)
SELECT distinct array[
(random() * 99999999)::integer,
...
0
votes
1answer
60 views
MySQL Read Speed and Partitioning on Separate Drives
Introduction
Simple project but for an heavy read load -90% reads- over a table(~20Milion Rows ever-growing where I have to boost performance and ensure response low time for read queries) that was ...
2
votes
2answers
124 views
MySQL replication: most important config parameters for performance on slave server?
I'm setting up a mysql master-slave configuration, where slave is located on a much weaker sever.
Since, if I understand correctly, slave only works on updates/inserts, what are the most critical ...
1
vote
4answers
140 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 ...
2
votes
2answers
103 views
Optimizing bulk update performance in Postgresql
Using PG 9.1 on Ubuntu 12.04.
It currently takes up to 24h for us to run a large set of UPDATE
statements on a database, which are of the form:
UPDATE table
SET field1 = constant1, field2 = ...
0
votes
2answers
35 views
How to design database table to store process status?
I have an application (ProcessMonitor) that monitor some constantly running process at fixed interval (like 30 seconds, but can be changed by user) and store the process status to a database table, ...
0
votes
1answer
48 views
Efficient way to perform approximated search?
I have to perform a join between table_a and table_b, using three fields as key being one of them the date of the event, say, both tables have id1, id2 and evnt_time for eache record.
As it happens ...
0
votes
0answers
18 views
Table partionning problem
I need your help for a partionning problem. We are using a "log_event" table which log a lot of events sent by our players (subscription, connection, play, share, etc...). We insert 5,000 row / s in ...
0
votes
0answers
43 views
one vs two column index difference when doing JOIN query?
Let`s suppose that alfa,beta and gamma contains milions of rows so we need to create indexes obviously to get optimal performace for this query :
SELECT * FROM alfa
JOIN beta on beta.id = ...
0
votes
2answers
37 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 ...
0
votes
1answer
56 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 ...
5
votes
1answer
97 views
Start/Stop MySQL
I'm seeking help to understand what happens when the following command line is executed:
root@prodn$ service mysqld stop
Yes, it shuts down the MySQL server so access to it is no longer available ...
1
vote
1answer
74 views
How to enhance the SQL query performance for thousands and millions of huge data
Now Our team are involved in a forum data analysis project. Its target data is so huge(I think). We should find the potential informations from it. Such as the popular products,the customers ...
3
votes
1answer
106 views
Simple MySQL query randomly takes forever
I'm having an issue on my server with a simple PHP send emails script that runs every minute via a cronjob. The script contains a MySQL query that runs very fast most of the time, but randomly will ...
1
vote
2answers
58 views
How should I store multiple relationships (many posts to many categories)?
I have posts stored in a posts table and I want each post to have multiple categories, what is the most efficient way to store the categories and their relationships ?
I thought of it this way first:
...
1
vote
1answer
102 views
Switching to NoSQL for native JSON use?
I am rather comfortable writing concrete schemas with explicit primary keys, foreign keys, indexes, views and stored procedures. For queuing I use a NoSQL solution called: Redis.
Recently I heard a ...
3
votes
2answers
133 views
Why use separate databases for high traffic/volume tables?
While looking at the database structure of an application I am using I recognized that it uses 3 different databases on the same SQL Server instance for different things.
The first one contains the ...
4
votes
1answer
91 views
.mdf vs .ldf Performance considerations
I just learned from an answer to this question that the .mdf and .ldf files that SQL Server uses are an important pair for the database. I previously thought the .ldf was just a non-critical log for ...
0
votes
0answers
14 views
MySQL shared server regular lockup
I have a web/ database server with 5 websites on it, all of which execute fairly complex queries regularly.
Some of these queries appear in the slow log and take around 0.6-0.8 seconds. However I ...
5
votes
3answers
151 views
How to optimize a query that's running slow on Nested Loops (Inner Join)
Consider the following simple query (only 3 tables involved)
SELECT
l.sku_id AS ProductId,
l.is_primary AS IsPrimary,
v1.category_name AS Category1,
...
2
votes
2answers
69 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 ...
2
votes
1answer
59 views
PostgreSQL concurrent increment of counter
I need to maintain a statistical table for a project, composed by a list of items and their usage (Think about something like a website in which you would like to count pageviews). Each time an item ...
1
vote
1answer
68 views
Can putting mysql DB into memory or having the innodb_buffer_pool_size match the size of DB increase performance?
We have a mysql database that has roughly 80 gigabytes (GB) of data using inno_db engine. We are looking to increase performance on the database (we looked at the slow log and gone through and ...
