improve linq query performance

length of all Deleted Values C. If the waste exceeds 20%, the index needs to be rebuilt.Alter index acct_no_idx rebuild;D. Or sort the indexes.Alter index acct_no_idx coalesce; 2) Mark unused IndexesA. Start monitoring index usageAlter index HR. emp_name_ix monitoring usage;B. Stop using monitoring indexes.Alter index HR. emp_name_ix nomonitoring usage;C. query the index usageSelect index_name, used from V $ object_usage;Deleting unused indexes ca

can use sessions, but devices that do not work and it will clear sessions as soon as possible and will disappear. We can use a database, but this data is most likely that our system has no critical slowness. It is easy to use memcached: $ user_id = 123; // The current user's ID cache now lets us cache database results to truly improve your Web applications. Database query is usually the biggest bottleneck

the same function.11, the Str_replace function is faster than the Preg_replace function, but the efficiency of the STRTR function is four times times the Str_replace function.12, if a string substitution function, can accept an array or character as a parameter, and the parameter length is not too long, then you can consider an extra piece of replacement code, so that each pass argument is a character, rather than write a line of code to accept the array as the

Improve PHP performance by caching database results (3 ). Adding a table to the previous section of existing registration describes how to use the change notification service to notify the database when the registration object (ORDERS table in the preceding example) is changed. But from Add a table to an existing registration The previous section describes how to use the change notification service to enab

part. When you need to create a Exception, the JVM has to say: Don't move, I want to save a snapshot of what you are now, so stop the stack and the stack operation temporarily. Stack traces contain not only one or two elements in the runtime stack, but each element in the stack.If you create a Exception, you have to pay the price. Fortunately, the overhead of catching exceptions is small, so you can use Try-catch to wrap the core content together. Technically, you can even throw an exception at

optimal solution. This parameter is used to set the optimal solution for Oracle. If the value is too large, it takes a long time to calculate the optimal solution. The default values of oracle805 and 8i are 2000. We recommend that you change the value of 8. The default value of 9i is 2000.6. Adjust sorting Parameters(1) sort_area_size: the default sort_area_size used for sorting is 32 K, which is usually a little small and can be set to 1 m (1048576 ). This parameter cannot be set to an excessi

[2]: s = set (r) # occupies 588 MB of memory In [3]: d = dict (I, 1) for I in r) # Occupy 716 MB of memory In [4]: % timeit-n 10000 (10 ** 7) -1 in r10000 loops, best of 3: 291 ns per loopIn [5]: % timeit-n 10000 (10 ** 7)-1 in s10000 loops, best of 3: 121 ns per loopIn [6]: % timeit-n 10000 (10 ** 7)-1 in d10000 loops, best of 3: 111 ns per loop Conclusion: the memory usage of the set is the minimum, and the dict running time is the lowest. 9. Reasonable Use (generator) and yield (memory savi

a large amount of time is spent on running the background job bibctl _ * (the program is rsbatch_execute_prozess. Rsbatch_execute_process is used to generate Sid. If you do not directly query the data in this DSO output report, you can remove the "generate Sid (SID generation upon activation)" option in the DSO maintenance interface. You can find this option in the Settings section on the DSO maintenance interface .. -Adjusting relevant parameters in

Skills | performance | skill | Performance Brief introduction: General a website's homepage visit quantity is biggest, if your website's homepage opens very slowly, Your customers will be leaving your site. Usually we cache data that needs to be complicated or query the database or generate static Web pages to improve

scenario 　　 ▲b*tree optimized data access simulation scenario Dong through Alibaba's real application scenario, describes how to use the table storage to improve performance. First, the scene introduction: 1, table verybigtable contains 30 columns 2, the record number of the table is 50,000,000 3, the average per user is about 300 4, of which 2 columns belong to the detailed Description fie

For performance reasons, put the-exec operator closer to the back, the better. This can avoid unnecessary processes. The find Command needs to read each index node in the directory tree it searches for, so it is best to combine multiple contents into a single find command as much as possible. The method isfind.\(-typed-a-execchmod771{}\;\)-o\(-name"*.BAK"-a-execchmod600{}\;\)-o\(-name"*.sh"-a-execchmod755{}\;\)-o\(-name"*.txt"-a-execchmod644{}\;\)-o\

cache rather than from the backend database, which can significantly improve the application performance. Then, you will useThe drop method of the Cache_Lite_Function instance deletes expired data in the cache.Looking back at the example in this article, you may want to create two functions for the application to interact with the database: the first function will quer