To delete or to free
C++: delete vs. free and performance
In the sentence:     All the information you need is in these folders.   I would have expected to find:     All the information that/which you need is in these folders.   Why are those omitted? test class with Batch and Callout I have a problem with FeedItems in my Test class, it's very weird behaviour Does someone explain to me why this happens?  Callout Class  public with sharing class Callout {  public static void runProccess(Case[] records) {     Database.executeBatch(new CalloutBatch(records), 10); }  public static void send(Case[] records) {     Case[] toUpdate = new Case[]{};       for (case record : records) {         HttpRequest req = new HttpRequest();         req.setEndpoint('callout:test/SOME_URL');         req.setMethod('POST');         req.setHeader('Content-Type', 'application/json');         req.setBody('');         Http http = new Http();         HTTPResponse res = http.send(req);          Map&lt;String, Object&gt; response = (Map&lt;String, Object&gt;) JSON.deserializeUntyped(res.getBody());          toUpdate.add(new Case(Id = (Id) response.get('Id'), Status = (String) response.get('Status')));     }      update toUpdate;  } }   CalloutBatch Class  global with sharing class CalloutBatch implements Database.Batchable&lt;Case&gt;, Database.AllowsCallouts{  private final Case[] records;  global CalloutBatch (Case[] records) {     this.records = records; }  global Iterable&lt;Case&gt; start(Database.BatchableContext BC) {     return records; }  global void execute(Database.BatchableContext BC, Case[] scope) {     Callout.send(scope); }  global void finish(Database.BatchableContext BC) { } }   Test Class  @IsTest  private class CalloutTest { @IsTest static void shouldReaciveData() {     String status = 'Closed';     Case caseRecord = new Case(Type = 'Web', Status = 'New');     insert caseRecord;      //insert new FeedItem(ParentId = caseRecord.Id, Visibility='AllUsers', Type = 'TextPost', Body = '');      System.assertEquals(0, [SELECT Count() FROM Case WHERE Id = :caseRecord.Id AND Status = :status]);      Test.startTest();     Test.setMock(HttpCalloutMock.class, new CalloutTestMock(caseRecord.Id, status));     Callout.runProccess(new Case[]{caseRecord});     Test.stopTest();      System.assertEquals(1, [SELECT Count() FROM Case WHERE Id = :caseRecord.Id AND Status = :status]); } }   Mock Class  public with sharing class CalloutTestMock implements HttpCalloutMock {  private Id recordId; private String status;  public CalloutTestMock(Id recordId, String status) {     this.recordId = recordId;     this.status = status; }  public HTTPResponse respond(HTTPRequest req) {     HttpResponse response = new HttpResponse();      response.setStatusCode(200);     response.setBody('{"Id": "' + recordId + '", "Status": "' + status + '"}');      return response; } }   This code works, but when I uncomment insert FeedItem in Test Class I receive an error message:     System.CalloutException: You have uncommitted work pending. Please commit or rollback before calling out   Class.Callout.send: line 23, column 1   Class.CalloutBatch.execute: line 20, column 1   FeedItem doesn't have an impact on this functionality, (I don't have any Process Builders, triggers etc. on FeedItem object) SQL Server Max Memory not limiting use of RAM I would like your input on this. I have a sql server 2008r2 Ent. Ed. 64bit with 16 cores and 64GB RAM. There is one instance of SQL server patched fully as of 20111014.  The max ram is set to 60000MB. Amount of free ram is 0 according to task manager after a few days online.  If I change the max ram to below 53GB it will after a few days to stabilize and have some free ram.   It is the sql process that does allocate the ram according to task manager. How do i come to terms with what the problem really is? It goes without saying that i did alot of testing already but havn't solved this to my liking yet. and ohh we do not get the typical memory starvation lagging when the available ram is down to 0 free.  Update 1:  Inspired by another Q/A related to RAM on this page  . I used these two to see what the RAM is being used for.  SELECT TOP ( 10 )         [type] AS [Memory Clerk Type] ,         SUM(single_pages_kb) AS [SPA Mem, Kb] FROM    sys.dm_os_memory_clerks GROUP BY [type] ORDER BY SUM(single_pages_kb) DESC OPTION  ( RECOMPILE ) ;  SELECT  DB_NAME(database_id) AS [Database Name] ,         COUNT(*) * 8 / 1024.0 AS [Cached Size (MB)] FROM    sys.dm_os_buffer_descriptors --WHERE   database_id &gt; 4 -- system databases --        AND database_id &lt;&gt; 32767 -- ResourceDB GROUP BY DB_NAME(database_id) ORDER BY [Cached Size (MB)] DESC OPTION  ( RECOMPILE ) ;   The amount used shown by these are  first select 7948432    Kb second one 44030,57812  MB that is a total of about 52GB used by sql server... so where did the rest of my RAM go? :-) Task manager show right now cached 363, available 401, free 40 and sqlservr.exe has Memory private set 64 459 656. Max Ram set to 60000MB as before. How to influence the position of float environments like figure and table in LaTeX? Often when I mistype a command such as ls (e.g. I hit ENTER before I type 's') there is a long (~2s) delay after the terminal displays:  bash: l: command not found...   I can understand the reasons for a similar delay after an incorrect password is entered, per . But why delay after an unrecognized command? Does FAIL_DELAY in /etc/login.defs affect this also? Globally disable "include online search results" I'd wish to visit Dubai with my girlfriend, but after reading  and  I started to get a little worried about it. How should I book an hotel? Must I book two singles? Could it be a problem if we walk together in the city and go together to restaurants and malls without being married? Big tilde in math mode How do I get a really wide tilde?  I need to cover at least  abcdefghijklmnopqrstuvwxyz  The \widetilde command does not work. Nor using \stackrel with \sim. Is there any package or a method to force LaTeX to keep floating environments like table and figure closer to where they are declared? Why did Superman & Supergirl start to suffocate instantly when Luthor made our yellow Sun red? Spoiler Alert: If you haven't read all comics series &amp; story arc of New Krypton Saga viz. New Krypton, World of New Krypton, Last Stand of New Krypton, Superman: War of Supermen etc, drop this question right away!  While battling the evil alien Brainiac, Superman &amp; Supergirl discovered the long-lost bottled city of Kandor which was stolen from Krypton prior to its destruction. Superman re-enlarged the city on Earth, but it wasn't welcomed by Humans. Humans assaulted the city in which Kryptonian's leader Zor-El (Supergirl's father) was killed. Using highly evolved science, Alura (Zor-El's wife) created a new planet "New Krypton". Plus, she, as a new leader, freed General Zod from Phantom Zone to command new super military of New Krypton (every kryptonians had super powers due to yellow sun).  While New Krypton &amp; Earth were at cold war, Zod ordered his military to attack Earth. When military was in space, Sam Lane (Lois Lane's father) destroyed New Krypton by a trick making their race extinct again. Kryptonian military successfully crushed Earth's Mars defense facility &amp; they headed towards Earth.  When they were about to enter atmosphere of Earth:      Many Kryptonians died under the red sun because they couldn't survive in empty space. Its somewhat plausible because they weren't under yellow sun for long. But, what about Superman &amp; Supergirl? They did survive because they were under yellow sun for very long. But, why did they become very weak instantly? If the power draining rate by radiation of red sun was that high, how did Superman &amp; Supergirl survive?  Is this a plot hole? Or, am I missing something? How do I install OpenStack? How do I install ? Is there an easier way other than official installation instructions? Choosing numbers without consecutive numbers. In how many ways can we choose $r$ numbers from $\{1,2,3,...,n\}$,   In a way where we have no consecutive numbers in the set? (like $1,2$) Graph editor for shape key animation I have animation where object changes his shape using shape keys, and I want to make some animation smoothing with graph editor. Is there a way to use graph editor for shape key animation? obtain a three-term asymptotic solution EDIT:  The vector space for the $(\frac{1}{2},0)$ Representation is $\mathbb{C}^2$ as mentioned by Qmechanic in the comments to his answer below! The vector spaces for the other representations remain unanswered.  The definition of a representation is a map (a homomorphism) to the space of linear operators over a vector space. My question is: What are the corresponding vector spaces for the   $(0,0)$ Representation $(\frac{1}{2},0)$ Representation  $(0,\frac{1}{2})$ Representation $(\frac{1}{2},0) \oplus (0,\frac{1}{2}) $ Representation $(\frac{1}{2},\frac{1}{2})$ Representation infinite dimensional Representation? Is there any way to view which applications are accessing the Internet on Mac OS X? I think I remember a command line utility that did this, but I can't remember what it's called and a few Google searches turn up nothing. How do you get a bad transcript past Ph.D. admissions? When I read about , I see that they should appear as solution to prevent  and  but when I actually try to write a code which would use Lightning promises it still doesn't look like synchronous code, it still resembles both pyramid of doom and callback hell.  main: function(component, helper) {     helper.promise1(component, helper).then(         $A.getCallback(function(record) {             return helper.promise2(component, helper, record).then(                 $A.getCallback(function(){                     console.log("Success");                     helper.showToastMessage(component, "Great Success!!!!")                 }),                  $A.getCallback(function(errorMessage){                     console.log("Rejected by second promise2");                     helper.showToastMessage(component, "Failure " + errorMessage);                 })              )         }),          $A.getCallback(function(errors){             console.log("Rejected by first promise1");             let message = errors &amp;&amp; Array.isArray(errors) &amp;&amp; errors.length &gt; 0 ? errors[0].message :'Unknown error';             helper.showToastMessage(component, "Failure " + message);         })      ) }   Is that possible to refactor this code to look more like synchronous code and without callback hell or pyramid of doom? number of vertices in a self-complemntary graph Problem: Prove that the number of vertices of a self-complementary graph must be congruent to 0 or 1 modulo 4. I think my starting point would be that P4 and C5 are self-complementary and proceed by induction by adding P4s. I established the first step in a previous problem, but I need help on the induction step. i.e. proving that adjoining P4 will indeed yield a self-complementary graph. Windows 10 and Ubuntu do not dual boot (after multiple attempts to fix)