Slow applications? Screens taking too long to open? Animations hanging? In this article, we will share some tips with you for better development that will help you avoid this kind of performance issues in your E3 applications.<\/p>\n
WhileRunning <\/span>Events<\/span><\/p>\n Avoid using cyclical scripts. Sometimes, these kind of scripts are used in order to perform a certain type of animation on screen, or to get the current value of a given property or equation. Instead of creating a cyclical event to perform these functions (which can make the application underperform), most of the times you can simply use links, which will play these exact same roles without damaging the system. This happens because links are only checked when the source’s value (or property) changes.<\/p>\n In case you cannot use links to implement the intended result, it is advisable to create a user-generated event that will only be executed when one of these conditions is met.<\/p>\n Accessing Server objects via Viewer <\/span><\/p>\n Every time the value of a Server’s tag or property is asked via scripts in the Viewer with Application.GetObject<\/span> method, communication with the Server is established. Therefore, the more often this method is used, the more the Viewer will communicate with the Server, which leads to worse performance. However, there are some ways you can reduce the frequency of Application.GetObjects<\/span> in your application. For example:<\/p>\n Another suggestion to optimize this access to data is to use Set <\/span>command to create a reference to the object, and then copy the property’s value to an internal variable of the script. See the examples below:<\/p>\n How not to do it:<\/p>\n \u00a0\u00a0\u00a0\u00a0 If Application.GetObject(“Data.InternalTag1”).Value <= 10 then<\/span> How to do it:<\/p>\n \u00a0\u00a0\u00a0\u00a0 Set Tag1 = Application.GetObject(“Data.InternalTag1”)<\/span> Animations on screen <\/span><\/p>\n Never overlap several Figures to create animations. The right way to do it is to use just one Figure, and then create a link at FileName<\/span> property. Also, whenever you need a demo tag to animate a certain screen object, you should use a tag from the Viewer, because then the Viewer will not need to constantly access the Server to search for this tag’s value.<\/p>\n Historical E3Chart <\/span><\/p>\n Configure the query to return only the fields that will be used in the Chart. Preferably, use E3Chart’s automatic query option, because it will return only the necessary data, given the time limits configured on the horizontal axes.<\/p>\n Complex figures <\/span><\/p>\n Some image files are highly complex. This is the case of WMF files, which can lead animations to underperform, especially regarding backgrounds and colors. It is better to simplify these objects, so that the animations will be lighter. It is also advisable to use small, compact image files (for example, PNG or JPG), because the larger the file, the longer it will take to be transferred to the remote Viewer. Lastly, use the transparency resource carefully, especially when dealing with large figures, because this resource takes up a lot of processing.<\/p>\n Scripts sizes <\/span><\/p>\n Avoid longer scripts, and prefer small, simpler ones. However, you should notice that the number of lines in a script do not always indicate better performance, because some single-line operations (such as a script that performs a synchronous write in an I\/O tag, or access to the database, for example) can take a considerably long time to process.<\/p>\n Defragmentation<\/span><\/p>\n Use the defragmentation option for files belonging to the Domain, especially in very large applications. They can be significantly compacted, and this will enhance their performance.<\/p>\n Changing links between screen objects and Server objects at runtime <\/span><\/p>\n This task demands a lot of processing from the Viewer, because it will deactivate and reactivate links with Server objects. To change links between screen objects and Server objects, you should use the screens’ OnPreShow event, because this is where the screen objects’ links have not yet been activated.<\/p>\n Communication<\/span><\/p>\n Some points to ponder regarding communication settings:<\/p>\n Historic<\/span><\/p>\n When configuring the historic, set indexes to accelerate the speed of queries performed in the table. If the application has several historics, you can do one of the following to enhance its performance:<\/p>\n Queries<\/span><\/p>\n Viewer queries<\/span>: whenever you need to use a query via scripts in the Viewer (by using GetADORecordset <\/span>method), and the returned data is static, you should perform this query only once, and then store this data in Viewer tags. For example: Asynchronous queries<\/span>: to access the data from a Query via scripts (which can return too much data, or even several queries), you can use GetAsyncADORecordset<\/a> <\/span>method. This method, unlike GetADORecordSet<\/span>, does not hang the script while the query’s result had not been loaded. Instead, script execution continues, and the query’s result is returned at OnAsyncQueryFinish <\/span>event.<\/p>\n\n
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Application.GetObject(“Data.InternalTag1”).Value =\u00a0 Application.GetObject(“Data.InternalTag1”).Value +1<\/span>
\u00a0\u00a0\u00a0\u00a0 Else<\/span>
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Application.GetObject(“Data.InternalTag1”).Value = 0<\/span>
\u00a0\u00a0\u00a0\u00a0 End if<\/span><\/p>\n
\u00a0\u00a0\u00a0\u00a0 Dim Valor<\/span>
\u00a0\u00a0\u00a0\u00a0 Value = Tag1.Value<\/span>
\u00a0\u00a0\u00a0\u00a0 If Value <= 10 then<\/span>
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Tag1.Value = Valor +1<\/span>
\u00a0\u00a0\u00a0\u00a0 Else<\/span>
\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Tag1.Value = 0<\/span>
\u00a0\u00a0\u00a0\u00a0 End if<\/span><\/p>\n\n
\n
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\u00a0\u00a0\u00a0\u00a0 Set Consulta = Application.GetObject(“Dadta.Query1”)<\/span>
\u00a0\u00a0\u00a0\u00a0 Set Tag = Application.Item(“InternalTag1”)<\/span>
\u00a0\u00a0\u00a0\u00a0 Tag.Value = Consulta.GetADORecordSet()<\/span><\/p>\n