Questions tagged [performance]
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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When using an ORM, what are some things to watch out for in your database design
What are some database design gotchas to watch out for when you know the database will be accessed using a Object Relational Mapper (ORM) Wikipedia? Also see Entity Framework NHibernate or LLBLGenPro.
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MS SQL Server 2008: How to improve performance after deleting transaction log file
Due to the size of transaction log file (it grew up to 200 GB) I had to delete it because the disk was running out of space. I know this is not a good practice but anyway after that the performance is ...
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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 ...
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Performance implications of MySQL VARCHAR sizes
Is there a performance difference in MySQL between varchar sizes? For example, varchar(25) and varchar(64000). If not, is there a reason not to declare all varchars with the max size just to ensure ...
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Is it better to store calculated values or recalculate them on request? [duplicate]
Possible Duplicate:
Storing vs calculating aggregate values
At an old job, we had this database, it wasn't normalized rigth, some tables wheren't used anymore, it was patch after patch. In ...
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Guid vs INT - Which is better as a primary key?
I've being reading around reasons to use or not Guid and int.
int is smaller, faster, easy to remember, keeps a chronological sequence. And as for Guid, the only advantage I found is that it is ...
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Which collation should I choose for a muiti-language website?
Does a collation have any influence over a query speed? Does the size of a table change depending of the collation?
If I want to build a website that must support all possible languages (lets take ...
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Is there a performance gain by handling data with stored procedures versus feeding it into functions after retrieval?
Title sums it up. I'm reasonably well off with PHP, and comfortable getting it to do what I need it to with values pulled from MySQL, however in the interest of expanding my knowledge I've been ...
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How do you tune MySQL for a heavy InnoDB workload?
Assuming a production OLTP system with predominantly InnoDB tables
What are the common symptoms of a mistuned/misconfigured system?
What configuration parameters do you most commonly change from ...
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For a MySQL query, how do you determine physical and logical I/O?
I'm used to having a showplan in Microsoft SQL and have gotten lazy with using tools to tune MySQL queries. How can I determine physical/logical I/O for a query in MySQL? (EXPLAIN shows the index ...
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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, ...
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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 ...
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In Google App Engine, what is the most effective many-to-many join model?
The BigTable design rejects many of the philosophies of standard relational models, explicitly preferring denormalization to a big host of tiny tables.
One of the larger areas where this is a problem ...
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What are the performance implications of polymodels versus normal Bigtable models in Google App Engine?
What produces the best performance in regular Google App Engine use, a polymodel or a normal "Bigtable" model?
The polymodel, effectively, creates a column in the parent table called "class" which ...
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Where can I find the mysql slow log?
Just as the title says, where can I see it ?
Are there any config options for it ( like how many ms would determine if a query is slow or not ) ?
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How can I optimize a mysqldump of a large database?
I have a symfony application with an InnoDB database that is ~2GB with 57 tables. The majority of the size of the database resides in a single table (~1.2GB). I am currently using mysqldump to ...
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To 'DBCC SHRINKDATABASE' or Not To 'DBCC SHRINKDATABASE': That's the question
We're freeing lots of space in a SQL Server 2008 R2 database -a Loooot! enough to care about- (we're dropping lots of unnecessary data). but the database file conserves its file size. we want to ...
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SSIS 2008 painfully slow to import CSV
I am using SSIS to import a 25,000 row CSV to an empty table. The table has a primary key that is populated as the data is inserted. I am using an ADO.Net destination.
What reasons are there why ...
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What is wrong in debunking myths about clustered indexes?
What is wrong in code. or its results, illustrating that clustered index is evil [1]?
and how to de-debunk, i.e. to return to customary myths and best practices?
[1]
Debunking myths about ...
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SQL Filegroup degrading performance
On our dev boxes, our database resides entirely in the PRIMARY filegroup, and everything works fine.
On one of our production servers, recently upgraded from 2005 to 2008, we noticed it was ...
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SQL Server - Temporary vs. Physical Tables
A movement is afoot in my place of employ to move away from using #temp tables and instead to use permanent physical tables with SPIDs. Whenever one would have previously INSERTed INTO a #temp table, ...
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Performance hit using CAST in T-SQL
We have a SQL generator that emits SQL conditional statements generically for specified fields (which for the sake of discussion: we will label as myField).
If myField is of type NVARCHAR, we can ...
Ryan Delucchi
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Using IF in T-SQL weakens or breaks execution plan caching?
It has been suggested to me that the use of IF statements in t-SQL batches is detrimental to performance. I'm trying to find some confirmation or validate this assertion. I'm using SQL Server 2005 ...
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Is there a performance hit by breaking out tables into different schemas in SQL Server?
Is there any kind of performance hit when querying by placing tables in different schemas in SQL Server.
For instance if I had 2 tables, Table1 and Table2, and put Table1 into the test schema and ...
pms1969
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Is there an equivalent of "OPTION(RECOMPILE)" or "WITH RECOMPILE" for an entire connection?
I'm curious. Is there any way to prevent SQL query execution plans from being cached for an entire connection's duration?
Can I run a command that basically says, "use OPTION(RECOMPILE) for all ...
kamens
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Which is faster join
Which is faster
SELECT * FROM X INNER JOIN Y ON x.Record_ID = y.ForignKey_NotIndexed_NotUnique
or
SELECT * FROM X INNER JOIN Y ON y.ForignKey_NotIndexed_NotUnique = x.Record_ID
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query plan caching (sql server)
Is there a measure of time frame as to which the execution plan of inline queries will cached?
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Help improving SQL Server 2005 query execution time
One of my stored procedure has long execution time (average around 4 to 7 minutes). I want to make it run faster.
I am looking at the execution plan and two things are contributing most of the cost. ...
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