![]() ![]() Any further insight would be much appreciated. I know absolutely nothing about how the collections are actually implemented, or the implementation differences between a dynamic and static array. In short, they're all viable alternatives for my project (except for the 1st and last methods, first because of its slowness, last because I need dynamically resizable arrays). I was also suprised by the mapped collection's key lookup speed - much, much faster than indexing and comparable to all other methods except the static array. I was astounded by the difference between using a for-loop and a for-each loop to access an indexed collection's objects. I would have assumed that adding would be slower for the other methods, due to the need for resizing, while Getting each object would be no faster than a dynamic array. Strangely enough, much of its speed gains were in Getting rather than Adding. The get-loop was a for-loop using an index from 1 to 100,000, as is typical for an array.įinally the static array typed was simply an array of type SpeedTester, which was initialised with 100,000 slots. Each time a variable is added, the size of the array was expanded by 1 slot (using ReDim Preserve). However, for the Get loop, instead of using a for-loop with an index, I used a for-each loop.ĭynamic array typed was a custom class containing an array of type SpeedTester. The next two methods were identical to the first two in the way variables were added to the collection. These objects were then accessed in a for-loop using an index from 1 to c.Count The first were added with no key, the second was added with a key which was the object's long property converted into a string. The methods Collection Indexed and Collection Mapped involved holding the objects in a collection. The results are as follows: Method Avg Add Time Avg Get Time Total TimeĬollection Indexed For Each 0.334 0.033 0.367Ĭollection Mapped For Each 1.084 0.039 1.123 130 different freestyles in speed stacking (5 months practice of cup. I performed 3 rounds per method, and averaged the times for the And and get loops. Re: Be on the Speed Stacks Stack Fast DVD. Then I did a second loop, which involved accessing each object in the collection/array and assigning the object's long property value to a new variable of type long. ![]() The value of the variable was the value of the loop index (between 1 and 100,000) I followed Tim Williams's advice and did some speed tests.įor each type of collection/array, I first added 100,000 objects of class "SpeedTester", which was simply a shell object holding a long variable (with get/set properties). Does this apply to non-keyed collections, or only key-value-mapped collections? How much slower is it to use variants than typed objects? Note that I will always be casting the variant objects in the array directly to a typed variable upon retrieval, a la: Dim myObject As M圜lassĭoes casting improve speed, or does vba still have to perform all the type-checking associated with variants?Īlso, would this second option be faster than using a non-keyed Collection? I have read that Collection iteration is slow, that they are designed for lookup. Obviously this is a lot less work, but I am concerned about speed. The second option is to develop a single 'List' class, with the same methods, using the Variant data type. The first option is to develop a 'List' class for each object type, with methods for adding objects (and expanding the array), getting the First and Last indexes and the object count, and retrieving an object by index (the latter 4 will include error handling in case the array is empty). Mostly I will be iterating through arrays, thus use of a keyed collection is not ideal. An array may hold any number of objects, potentially thousands, of a single class, but not objects of multiple classes. I am getting the below error Caused by: : The table does not comply with the requirements by an external plugin.My project requires a bunch of dynamically-resizable arrays for different objects. Url=jdbc:mysql://server-host:3306/schema?serverTimezone=UTC changeLogFile=changelog/db-changelog-master.xml JDBC connector version is mysql-connector-java-8.0.26īelow are my liquibase properties.I am trying to run below create statement in liquibase - liquibase formatted sqlĬonstraint JOB_INST_UN unique (JOB_NAME, JOB_KEY) ![]()
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