The tag has no wiki summary.

learn more… | top users | synonyms

23
votes
8answers
6k views

Tool to generate large datasets of test data [closed]

Many times when trying to come up with an efficient database design the best course of action is to build two sample databases, fill them with data, and run some queries against them to see which one ...
18
votes
5answers
751 views

Should Query Tuning be Proactive or Reactive?

As a software developer and an aspiring DBA, I try to encorporate best practices when I design my SQL Server databases (99% of the time my software sits on top of SQL Server). I make the best ...
17
votes
2answers
576 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, ...
13
votes
2answers
4k views

How do I properly perform a MySQL bake-off?

I want to performance test (aka bake-off) MySQL server rpm against some other forks such as Percona server, MariaDB, and possibly some others. I'm hoping that by asking this question I can better ...
10
votes
4answers
1k views

What tools are there to generate test data for SQL Server?

As you can see from another question of mine, generating test data is my theme right now. At this point, I'm still generating my test data by hand. However, this process always generates small ...
9
votes
2answers
7k views

SQL Server commands to clear caches before running a performance comparison

When comparing the execution time of two different queries, it's important to clear the cache to make sure that the execution of the first query does not alter the performance of the second. In a ...
9
votes
1answer
555 views

Definitive list of steps for SQL Server baseline testing?

Before running a performance test / baseline for an app that uses SQL Server, I want to be able to set the instance to a "clean" state, without restarting the instance. There are steps I tend to ...
8
votes
4answers
6k views

Aggressive Autovacuum on PostgreSQL

I'm trying to get PostgreSQL to aggressively auto vacuum my database. I've currently configured auto vacuum as follows: autovacuum_vacuum_cost_delay = 0 #Turn off cost based vacuum ...
8
votes
3answers
3k views

How to stress test a SQL server?

I've been tasked to stress test our MSSQL Server and MySQL Server. I would like to know if there are any tools or scripts which I could use on our current systems and the new system to compare ...
7
votes
3answers
1k views

Testing stored procedure scalability

I have an email application that will be called upon to deliver to the UI the number of new messages for a given user on each page load. I have a few variations of things I am testing on the DB level ...
6
votes
3answers
509 views

Single query sending and retreiving duplicate data on MS SQL Server?

Very odd thing happening. It would appear that all queries against a particular database in our system are periodically "running slow". Ie "normal speed" for 5 minutes then slow for 5 minutes ...
4
votes
2answers
238 views

How to compare performance of two versions of a function?

I just saw this function definition: create function dbo.f (@a int, @b int) returns integer as begin return case when not exists (Select * from t1 where t1.col1 = @a) AND @b ...
4
votes
2answers
449 views

Multi-threaded replay of master activity for load/performance testing

Does anyone know of any existing tools/products that accomplish what I'm trying to do? After searching around for a bit the only thing I could find surrounding what I'm trying to accomplish is ...
3
votes
3answers
793 views

Database Performance Tuning

I have a MySQL backend, MS Aaccess front-end system that is nice and responsive over a local network but becomes sluggish over a broadband connection. I haven't done any performance tuning as of yet. ...
3
votes
2answers
246 views

Pipe psql timing to file

I am currently using \timing on to do some simple performance testing in Postgres. I would like to run many queries and pipe the timing results to a file. However, all of the options I have tried ...
3
votes
1answer
119 views

How to track overhead of Change Tracking in SQL Server

We're going to implement a solution based on Change Tracking feature from SQL Server. Before going in production (even after), we'd like to keep track of the overhead the CT will introduce. Once in ...
3
votes
1answer
290 views

Can't understand results of pg_stat_statements view

I configured my postgresql.conf (my version is 9.1) with the normal persistent configuration: shared_preload_libraries = 'pg_stat_statements,plperl' custom_variable_classes = ...
3
votes
1answer
440 views

PostgreSQL WAL Archiving: Does having archive_mode set to 'on' without copying logs cause performance issues?

Using PostgreSQL 8.4/CentOS 6: if I set the archive_mode parameter to on in postgresql.conf, but don't actually store the generated WAL files anywhere via the archive_command parameter, is there any ...
2
votes
2answers
2k views

Generate sample data for an Oracle database [closed]

Good morning, What free [or trial] software can I use to generate sample data for an Oracle database? I've been trying with various tools, but none work. Thanks for all suggestions, Alec Taylor
2
votes
2answers
538 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
1answer
63 views

Can one assign a performance score to a stored proc to compare performance of 2 procs

I have an existing stored procedure, and an updated version of that same stored procedure where changes have been made, but the same resultset is returned. The updated version of the procedure ...
2
votes
2answers
152 views

Which performance can I expect?

I'm running a Postgres 9.1 database on a Debian Squeeze server. It's a paravirtualized XEN guest system with 4G RAM and 1 CPU core, based on a i7-2600 host system with Linux software-RAID1. I'm ...
2
votes
1answer
144 views

Good tool for simulating many threads doing INSERTS UPDATES SELECTS and DELETES on an ODBC database?

I've done load testing on a web application already using tools like JMeter, and tested my database for transactional integrity. But are there any tools for testing an ODBC connected database (like ...
2
votes
1answer
703 views

AWS performance of RDS with provisioned IOPS vs EC2

Has anyone done a performance comparison of AWS RDS with the new provisioned IOPS vs EC2? I've found plenty of non-high IOPS RDS vs EC2 but nothing with the new high IOPS feature in RDS.
2
votes
1answer
485 views

How to calculate query that access system view cost in Oracle?

For a query that returns if there are any active transactions within current session , SELECT COUNT(*) FROM v$transaction t INNER JOIN v$session s ON (t.ses_addr = s.saddr ) INNER ...
2
votes
0answers
156 views

A Tool to Manage Tracking Query Performance Improvements [duplicate]

I'm building a BI system on SQL Server 2012. I have a test set of data with some tens of millions of rows. Currently many functions and stored procedures are unacceptably slow. I'm looking for a tool ...
1
vote
2answers
236 views

Do natural keys provide higher or lower performance in SQL Server than surrogate integer keys?

I'm a fan of surrogate keys. There is a risk my findings are confirmation biased. Many questions I've seen both here and at http://stackoverflow.com use natural keys instead of surrogate keys based ...
1
vote
2answers
1k views

Stress test MySQL with queries captured with general log in MySQL

Is there any tool available which can do stress testing using the log file created by MySQL general log? After a lot of search on google I found few stress testing tools which only use some benchmarks ...
1
vote
1answer
198 views

How to do a simple SELECT/UPDATE/DELETE performance test?

I have a table which might be causing excessive delays during insertion of new records. I'd like to run a test against the database, measuring how long it takes to select, insert, and delete from the ...
1
vote
1answer
436 views

PostgreSQL vs MySQL benchmarks when a 2nd level cache is included

Has anyone been able to find any benchmarks comparing PostgreSQL and MySQL performance when they are used by a system through Hibernate (or another comparable ORM) and the 2nd level cache (backed by ...
1
vote
1answer
65 views

Any general reasonable performance tests for DBs on application server and DBs on separate server?

My company are planning to move the DBs (SQL Server 2008 R2) from the application server to another server (random distance). All servers are Windows 2003 x86. Are there any general performance tests ...
0
votes
1answer
2k views

Why does max_used_connections status not get refreshed automatically once it reaches max_connections, even though the Threads_connected falls down

I always wonder, why does the max_used_connections value not come down, once it reaches the peak value of max_connections? I always flush the status and bring down this value to avoid DB connection ...
0
votes
1answer
189 views

How to measure a perfomance of SQL Server database? [closed]

I have the task to improve the performance of a SQL Server 2012 database (one of 4 in an instance) by 60% confirmed by corresponding statistics. So, I need to measure "performance" of the RDBMS ...
0
votes
1answer
36 views

Is it possible that a same INSERT operation performance will suddenly degrade?

I am working on a code performance test project. Let me first describe the enviorment: MsSql Server, Ria Service The automation test runs a big set of Test cases in midnight where have minimum ...
0
votes
1answer
95 views

Maintain stable data in a database

I am doing Performance evaluation of my application. The size of database is around 20GB. I am using jMeter as a performance evaluation tool. Here each performance test (ie., Each jMeter run) there is ...
0
votes
1answer
40 views

MySQL: Use Sysbench on Windows

Sysbench is a tool to analyze the MySQL performance. I downloaded it and extracted but there is no executable file. Files having extensions like .sh or .c or .h are available. I gone through the ...
0
votes
0answers
212 views

hstore vs redis performance wise (without durability) [closed]

How do PostgreSQL's Hstore and Redis compare performance-wise? This question was asked here, but I would like to compare with a PostgreSQL configuration without durability guarantee, i.e. with ...
0
votes
0answers
31 views

How to make a consistent database dump with log recording for a later replay on MySQL?

This article explains how to collect MySQL load and how to replay it. My question is how to make a backup on a loaded server in a way that a recorded log will be consistent and not fail during replay ...