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.

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14
votes
7answers
380 views

Which of these table designs is better for performance?

I have been asked to create something which tracks the daily cost to collect on accounts, and I am trying to figure out a database table schema that would support this. Here's what I know Company ...
6
votes
3answers
4k views

Too Many Connections

I'm using MATLAB to feed the database but after a time I'm getting a too many connections error. I always using opendb and closedb in pair. Is it to fast the feeding? Do I have to wait after I ...
21
votes
3answers
5k views

Efficency of stored procedures vs raw queries

I have read much on both sides of this debate: is there a signficant performance gain to be had by using only stored procedures over raw queries? I am specifically interested in SQL Server but would ...
11
votes
2answers
151 views

A question on SARGability

I just need to confirm that I understand something correctly: I recently viewed an SO question in which a user posted an answer in Linq like: from p in db.table where p.column.AddMinutes(1) > ...
5
votes
1answer
169 views

How big of an impact does NUMA really have?

I was reading up on Non-Uniform Memory Access (NUMA) and I was wondering how much of a difference it can really make? Another way to word that, what level of throughput is required before this ...
8
votes
2answers
6k views

Performance of a Trigger vs Stored Procedure in MySQL

A post here on DBA.StackExchange (What are the best practices for triggers to maintain a revision number on records?) has spawned an interesting question (at least, interesting to me) regarding ...
15
votes
2answers
6k views

How to create an index to speed up an aggregate LIKE query on an expression?

I may be asking the wrong question in the title. Here are the facts: My customer service folk have been complaining about slow response times when doing customer lookups on the administration ...
13
votes
3answers
2k views

Is there any point in undersizing VARCHAR columns?

Googling around there seems to be mixed reports whether the size of a VARCHAR2 column in Oracle impacts performance or not. I would like to give the question of VARCHAR size a little twist and hope ...
9
votes
2answers
9k views

Which performance counters can you look at on a SQL Server Instance to determine it's performance and over all health?

I am a student from Fontys University in Eindhoven, and I am currently carrying out a series of interviews to help with the development of a SQL Server tool and I would like to get feedback from the ...
13
votes
10answers
1k views

What are the top 3 performance Issues that you encounter with your SQL Servers?

I am a student from Fontys University in Eindhoven, and I am currently carrying out a series of interviews to help with the development of a SQL Server tool and I would like to get feedback from the ...
5
votes
3answers
382 views

Using DTA vs. evaluating DMVs?

Currently I am confronted with a production SQL Server database where someone had added almost all missing index proposals from DTA. Form How to determine if an Index is required or necessary I have ...
5
votes
3answers
12k views

Optimizing InnoDB default settings

I looked into my.ini and saw various default settings. My database is running on a single stand-alone PC. I want to optimize the performance of InnoDB and MySQL in general for performance. There is no ...
10
votes
2answers
444 views

@table_variable or #temp_table

I have a big user defined table type variable that has 129 columns. I will store around 2000-3000 records in this table variable at a time and pass it to various stored procedures and functions to get ...
5
votes
1answer
454 views

how to improve performance by using or not using table variables

I have a table variable: DECLARE @to_process TABLE ( [Id] [bigint] NOT NULL, [SequenceId] [bigint] NOT NULL, ... ) INSERT INTO @to_process ( Id , SequenceId ... ) SELECT ...
1
vote
0answers
154 views

SQL Server and Perfmon [duplicate]

Possible Duplicate: SQL 2008 Server agent cant see perfmon counters I'm trying to setup SQL Server Perfmon counters on a Windows Server 2003 with SQL Server 2005 SP3. I'd like to run ...
6
votes
2answers
556 views

MySQL: Does the order of the fields in a table make a difference in performance?

Specifically I am wondering if I should place all my fixed length fields like int, timestamp, char at the beginning of the CREATE TABLE and place all the variable length like varchar at the end. ...
12
votes
4answers
11k views

SQL Server statements intermittently slow on SQL Server 2008 R2

On one of our customers, we've been having some performance issues on our application. It's a .NET 3.5 web app that is consuming and updating data on a SQL Server database. Currently our production ...
7
votes
3answers
806 views

More Databases Per Sql Server 2005 Instance

Our company currently hosts about 400 databases per SQL Server 2005 instance. 500-600 databases and we see performance start to deteriorate. Database size ranges from 50mb to 40-60gb in the extreme, ...
1
vote
2answers
255 views

dm_db_missing_index_details - does the order of equality_columns matter

I've been investigating some databases using the dm_db_missing_index_group_stats DMV, and have a question about the equality_columns field in the dm_db_missing_index_details view. MSDN says that this ...
4
votes
1answer
2k views

Storing hex values as strings or integers?

I've inherited a database that uses sets of 32-byte hex strings to attempt to uniquely identify objects. Each string is called a fingerprint and each object can have up to 20 fingerprints. I'm ...
2
votes
3answers
758 views

Best database choice for a highly scalable web ticketing system?

Essentially, we are developing using Ruby on Rails and want to make a highly scalable ticketing system. Essentially we will have a small database (containing event details and tickets sold) that will ...
5
votes
3answers
2k views

Optimizing query using view on EAV structure

An application is writing into a database that follows an EAV structure, similar to this: CREATE TABLE item ( id INTEGER PRIMARY KEY, description TEXT ); CREATE TABLE item_attr ( item ...
0
votes
1answer
554 views

Performance problem caused by joining with the result of a scalar function?

In the following example the performance of the first version using only one SQL query is very bad. The problem is the last join. When I store the result of the left side into a temporary table and ...
5
votes
3answers
4k views

Using MySQL triggers or transactions?

I want to ask your opinion in using MySQL triggers or transactions in a website. Actually I have a history payment table with - UserId | OperationId | Comment | Credits | Sign (debit or credit). So ...
20
votes
2answers
7k 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 ...
2
votes
2answers
576 views

Degrading PostgreSQL 8.4 write performance

Load testing of postgresql 8.4 for OLTP application suitability resulted in unpleasant situation when throughput of the database significantly degraded over time from thousands of write transactions ...
8
votes
1answer
8k views

Auto Update Statistics in SQL Server 2008R2: Why do some statistics remain stale despite a large number of row inserts?

During investigation of a slow query it appeared that the execution plan was exceptionally suboptimal (A nested loop performing 9 million executions of a seek where the estimated number of executions ...
4
votes
1answer
818 views

Need help with ASYNC_NETWORK_IO

We have a SQL Server 2005 server that is serving up 20 websites, one of which is our custom CMS, and a few other micro sites. I am new to this and just started looking at the databases here. The ...
3
votes
5answers
2k views

Setting up a Redundant Sql Server 2008 Configuration While Retaining High Performance and Minimal Downtime

We have a situation where we are moving to a new hosting facility and are attempting to configure our new database environment. However, none of us are formal DBA's so a lot of what we are doing is ...
5
votes
1answer
697 views

Indications from obscenely high Operator Costs in Query Plan?

I have a monthly ETL process that's too complicated to explain here, but basically we get a large amount of customer data, bulk load it into various tables, then run a series of build processes. The ...
12
votes
2answers
6k views

Reasons for occasionally slow queries?

We are running MySQL 5.1 on Windows Server 2008 R2. We have been doing some diagnostics on our database of late and have found some disturbing artifacts which we can't explain. We added some code to ...
6
votes
4answers
979 views

How can I tell if my SQL Server DB performance is hardware-limited?

Testing an app currently under single-user load - as the test data has increased to production sizes (400k-2M rows per table), some SELECT sp's are not quite fast enough anymore (with limited test ...
3
votes
1answer
593 views

Sql Server Performance Degradation in moving from 2005 to 2008

I have sql server 2005 setup for my performance bench marking exercise and I have put same database on another server which has sql server 2008 and exact replica in terms of hardware configuration. ...
8
votes
2answers
14k views

MySQL 5.1 InnoDB Configuration / 24GB RAM - bi-xeon high load

i'm running a facebook app which currently has 300 - 600 concurrent users (and growing). To get the hardware ready for growing i changed my i7 / 12gb ram / 2x 80gb intel x25 ssd's (debian 5.0 / mysql ...
4
votes
3answers
1k views

Suggestion required for Large Database Optimization and performance

We are creating a large database with estimated growth rate 200 million+ records per annum. The database is use for analysis purpose and we will generate different tabular and graphical reports from ...
0
votes
2answers
1k views

How fast should I expect to load data on a high performance computer?

I am considering a model where I use PostgreSQL COPY to copy data from a file into a table. I was wondering what kind of performance to expect on high-end hardware. An interval in MB/s would be nice ...
6
votes
4answers
12k views

Optimising join on large table

I am trying to coax some more performance out of a query that is accessing a table with ~250-million records. From my reading of the actual (not estimated) execution plan, the first bottleneck is a ...
9
votes
1answer
3k views

noexpand hint for non-enterpise edition and performance

I have to use Indexed views to reach performance. As I can see from this comparison table standard edition does not support indexed views. But BOL says: Indexed views can be created in any ...
6
votes
2answers
1k views

Using totals on aggregates to improve performance

I have two tables: details and totals of these details. Details (Slow solution): select OrderId = r.OrderId , TotalQty = SUM(r.Quantity) , ...
3
votes
1answer
901 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 ...
4
votes
1answer
1k views

Ms-access ODBC calls for linked table behaviour

I'm curious if anyone knows how ms-access goes about generating ODBC calls for linked tables. The reason I ask is that I'm trying to make the front-end of a system super efficient and too minimise ...
1
vote
2answers
716 views

Performance tuning OLTP query

I have following sqls executed million times a day, single execution isnt an issue but executing million times causing some performance issues..Thanks in advance for your help! NOTE: data can change ...
3
votes
1answer
336 views

Badly performing query plan after adding ORDER BY to Full Text CONTAINS search

The following query is proving beyond my abilities to fix - hope someone can help. SELECT top 100 Id, Name, InsertDate FROM Foo WHERE CONTAINS(FooText, '"test*" and "hello*" and "goodbye*"') ORDER BY ...
36
votes
6answers
36k views

About single threaded versus multithreaded databases performance

H2 is a single threaded database with a good reputation regarding performance. Other databases are multi-threaded. My question is: when does a multi-thread database become more interesting than an ...
9
votes
4answers
2k views

How can I optimize this MySQL query further?

I have a query that is taking a particularly long time to run (15+ seconds) and it is only getting worse with time as my dataset grows. I have optimized this in the past, and have added indices, ...
3
votes
1answer
4k views

sqloledb vs sqlncli - Performance difference or just feature set?

I've been running through some Classic ASP code recently and was wondering if there was a performance difference between connecting using: ...
1
vote
1answer
1k views

Inner cursor performance issues

Before I tried to avoid using cursor because of performance issues. But now I have to do some calculations to reach some goals. I have a stored procedure that has a code like this: DECLARE ...
4
votes
3answers
7k views

How to reduce the log file size without shrinking it in SQL server

In SQL server, how do you reduce the log files size without (DBCC) shrinking it. I know shrinking the log file will free up some space, but will also cause fragmentation. Doing a checkpoint in simple ...
5
votes
1answer
830 views

Does MySQL still handle indexes in this way?

Dropping a duplicate index in MySQL was taking rather long, so while I was waiting I searched about it & found this post from 2006, talking about how MySQL handles ADD and DROP index. If a ...
4
votes
1answer
1k views

Indexing to improve performance of range queries

I've got a relation in a Postgres 8.2 database similar to this: CREATE TABLE foo ( foo_id varchar(160) NOT NULL, bar_id varchar(160) NOT NULL, created bigint NOT NULL, PRIMARY KEY ...