Questions tagged as 'desempenho'

Tagged questions
2
answers

Java variable declaration

There is some difference between the two statements: First: int a; int b; Second: int a, b; Which is better? Do variables get closer in memory or is this just myth? Is there any significant difference?     
asked by 05.10.2018 / 14:04
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Should I use int_least8_t or int_fast8_t?

I'm studying the type boundaries that c ++ 11 brought and noticed that there are officially several types of integers. In addition to the common int statement I can now declare: int8_t int_fast8_t int_least8_t In this question y...
asked by 28.02.2017 / 17:10
2
answers

Workaround problem with hot development in Java?

Problem situation: You are developing a web site and doing debugging on it. For example a users CRUD. For this you are using JavaEE 1.7, Eclipse Kepler and Apache Tomcat 7. However, to the development delongo, and already with the application...
asked by 31.05.2014 / 00:43
2
answers

NULL value in database x performance

I have always used a MySQL database for small projects and I never cared about the option "NULL when it is empty", that is, it was blank. Now I'm designing a large system, I would like to know the concept of using NULL value when the f...
asked by 21.10.2015 / 19:31
1
answer

Alternative String.replace ()

I have a flea behind my ear. I have a method that removes / changes some characters from the string, it's something like this: public static String replaceCharSet(String texto) { texto = texto.replace("&", "E"); texto = texto.re...
asked by 07.11.2017 / 14:27
1
answer

Why does bitmap indexing work well for low cardinality domains?

I have just read Chapter 29 of the Data Warehousing and OLAP overview On page 725, the author talks about indexing techniques to support high-performance access, this technique is called bitmap . That is how the question arose and consequ...
asked by 09.11.2017 / 15:40
1
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Manage DataTable with lots of information

I have here a "small" problem with a DataTable . From a SQL query I'm getting a huge amount of records (> 1,000,000 ), and although the query is relatively fast, loading DataTable from Fill() is extremely slow and, in some...
asked by 31.08.2018 / 15:32
1
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COUNT (*) x COUNT (1) x COUNT (id)

I would like to better understand the difference between these ways of using the counter: select COUNT(*) from tabela select COUNT(1) from tabela select COUNT(id) from tabela This question deals with performance between two ways, but wo...
asked by 17.09.2018 / 14:15
2
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Ternary operator performance

Recently I came across an assignment to a Boolean variable as follows: bool varTeste = (varEntrada == 100) ? true : false; I know this is the same as the code below: bool varTeste = (varEntrada == 100); The question is whether perform...
asked by 23.02.2018 / 15:29
1
answer

When relating two tables, is the correct side of SQL, PHP or whatever?

I have this doubt of what it is preferable to do when I need data from the two tables to get the result. I always did the comparison in PHP, but I learned the SQL relationship commands that could help. What is the most correct way to do it, p...
asked by 17.12.2016 / 21:44