[jira] [Commented] (CALCITE-3878) Make ArrayList creation with initial capacity when size is fixed

["Julian Hyde (Jira)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/CALCITE-3878?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17067966#comment-17067966 ] 

Julian Hyde commented on CALCITE-3878:
--------------------------------------

-1

I believe that JVM instrinsics make this happen automatically. Therefore I removed the code.

If your IDE is suggesting to add back the size argument, your IDE is misleading you.

> Make ArrayList creation with initial capacity when size is fixed
> ----------------------------------------------------------------
>
>                 Key: CALCITE-3878
>                 URL: https://issues.apache.org/jira/browse/CALCITE-3878
>             Project: Calcite
>          Issue Type: Improvement
>          Components: core
>    Affects Versions: 1.22.0
>            Reporter: neoremind
>            Priority: Minor
>              Labels: pull-request-available
>          Time Spent: 20m
>  Remaining Estimate: 0h
>
> I find many places in Calcite where _new ArrayList<>()_ is used, if the list is expected to be immutable or not resizing, it is always a good manner to create with initial capacity, better for memory usage and performance.
> I search all occurrences, focus on the core module, to make it safe, I only update local variables with fixed size and not working in recursive method. If the local variable reference goes out of scope, if resizing is needed, things will work normally as well, so no side effect, but for the "escaping" case, I am very conservative and do not change them.
>  
>  
>  



--
This message was sent by Atlassian Jira
(v8.3.4#803005)