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https://issues.apache.org/jira/browse/CALCITE-3878?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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neoremind updated CALCITE-3878:
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Description:
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.
was:
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, 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.
> 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: 10m
> 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.
>
>
>
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