improve linq query performance

54. improve PHP programming efficiency and introduce Cache mechanism to improve performance. 0. replace double quotation marks with single quotes to include strings. this will be faster. Because PHP will search for variables in strings enclosed by double quotation marks, but not in single quotation marks. note: only echo can be 0. use single quotation marks inste

ON For example, when we perform a query, the affected number of rows will always be returned. This message is only helpful for us to debug SQL statements, and there is no other help. We can disable this feature by setting SET NOCOUNT ON, this will significantly improve the performance and reduce the transmission of network traffic. In the stored procedure, we s

check whether global variables exist. 23. method calling seems to have nothing to do with the number of methods defined in the class, because I have added 10 methods before and after the test method, but the performance has not changed. 24. the methods in the derived class run faster than the same methods defined in the base class. 25. calling an empty function with a parameter takes seven to eight times to increment local variables. Similar method c

increment local variables. Similar method calls take nearly 15 times to increment local variables.26. Apache parses a PHP script two to ten times slower than parsing a static HTML page. Use static html pages and less scripts as much as possible.27. Unless the script can be cached, it will be re-compiled every time it is called. The introduction of a PHP cache mechanism can generally improve the performance

, parsing the operating system path requires less time.9, if you want to know the script to start execution (that is, the server to receive client requests) at the moment, using $_server[' request_time ' is better than time ().10. Functions do the same function instead of regular expressions.11, the Str_replace function is faster than the Preg_replace function, but the efficiency of the STRTR function is four times times that of the Str_replace function.12. If a string substitution function can

Inherited introduces the concept of multi-state query. For this type of query, the inheritance hierarchy and returned objects may be of different types, but inherited from the same base class. Suppose you want to query all products. The list of product objects is obtained from the polymorphism query, but the specific

This article describes the deferred execution of LINQ and Query Non-generic collections. Deferred execution From the perspective of LINQ query process, there are new types, collection construction, release, feeling inefficient, but the delayed execution mechanism of LINQ w

, but there was no performance change. 24. A method in a derived class runs faster than the same method defined in the base class. 25. Call an empty function with one parameter, which takes the same amount of time as performing a local variable increment operation of 7 to 8 times. A similar method call takes a time close to 15 local variable increment operations. 26, Apache parsing a PHP script time is 2 to 10 times times slower than parsing a stat

5.1.1 query non-generic Sets If you have carefully read the previous chapters of this book, you should be able to query the set data in the memory using LINQ to objects. However, there is another problem, that is, we think that we can operate on all types of sets, but in fact we can only query part of the set types. Th

Recently are in the use of NHibernate and database dealing, to tell the truth, I think nhibernate is better than ADO, but in some complex query nhibernate is not as good as ADO. No more nonsense, let's talk about performance optimizations for LINQ to NHibernate. 1th: It should be clear whether the current code is executed on the database or in memory (or when it

.25. Calling an empty function with a parameter takes seven to eight times to increment local variables. Similar method calls take nearly 15 times to increment local variables.26. Apache parses a PHP script two to ten times slower than parsing a static HTML page. Use static html pages and less scripts as much as possible.27. Unless the script can be cached, it will be re-compiled every time it is called. The introduction of a PHP cache mechanism can generally

base class. 25. calling an empty function with a parameter takes seven to eight times to increment local variables. Similar method calls take nearly 15 times to increment local variables. 26. Apache parses a PHP script two to ten times slower than parsing a static HTML page. Use static HTML pages and less scripts as much as possible. 27. unless the script can be cached, it will be re-compiled every time it is called. The introduction of a PHP Cache mechanism can generally

it is equivalent to increasing a local variable ). PHP will probably check whether global variables exist. 23. method calling seems to have nothing to do with the number of methods defined in the class, because I have added 10 methods before and after the test method, but the performance has not changed. 24. the methods in the derived class run faster than the same methods defined in the base class. 25. calling an empty function with a parameter take

choice to replace in with exists in many cases: Select num from a where num in (select num from B) Replace with the following statement: Select num from a where exists (select 1 from b where num=a.num) 14. Not all indexes are valid for queries, SQL is query-optimized based on data in the table, and when there is a large amount of data duplication in the index columns, SQL queries may not take advantage of the index, as there are fields in the table S

you can more accurately estimate the number of rows per step, the use of parallel running (there are write parallel related, can refer to), and so on, to obtain more resources to improve the efficiency of execution in fact, the example of the SQL after the split operation, formally because of this, Grants greater memory + parallelism for efficient execution.　　Summarize:In this paper, the optimization method is achieved by splitting a SQL statement, w