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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17
votes
2answers
599 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, ...
77
votes
6answers
56k 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 ...
8
votes
2answers
2k views

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 ...
12
votes
1answer
238 views

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 ...
109
votes
7answers
109k views

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 ...
3
votes
1answer
3k views

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 ...
1
vote
3answers
1k views

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 ...
1
vote
2answers
315 views

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 ...
4
votes
2answers
285 views

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 ...
12
votes
3answers
6k views

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, ...
8
votes
3answers
8k views

Performance Hit using CAST() in TSQL (SQL Server)?

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). So, if myField is of type NVARCHAR, we ...
7
votes
1answer
132 views

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 ...
2
votes
3answers
313 views

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 ...
2
votes
2answers
87 views

query plan caching (sql server)

Is there a measure of time frame as to which the execution plan of inline queries will cached?
2
votes
4answers
491 views

Help understanding SQL Server 2005 execution plan

One of my stored procedure has long execution time (average around 4 to 7 minutes). Now I trying to tweak it an make it run faster. I am looking at execution plan and two things I see that using ...