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https://issues.apache.org/jira/browse/IMPALA-10135?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Zoltán Borók-Nagy updated IMPALA-10135:
---------------------------------------
Description:
When Impala generates INSERT EVENTs it doesn't add the newly inserted datafiles.
The problem is that Impala misuses Sets.difference(set1, set2). From the API
doc at
[https://guava.dev/releases/28.2-jre/api/docs/com/google/common/collect/Sets.html#difference-java.util.Set-java.util.Set-]
"The returned set contains all elements that are contained by {{set1}} and not
contained by {{set2}}. {{set2}} may also contain elements not present in
{{set1}}; these are simply ignored."
So the name "difference" is a bit misleading, it's rather a subtraction between
set1 and set2.
Unfortunately Impala passes the parameters in wrong order:
Sets.difference(beforeInsert, afterInsert):
[https://github.com/apache/impala/blob/4cb3c3556e77ee24003383155ca5e1b70be4db6e/fe/src/main/java/org/apache/impala/service/CatalogOpExecutor.java#L4581]
So the result will be always empty.
There's another problem with INSERT OVERWRITEs, in that case we never fill the
data files of the insert event.
was:
When Impala generates INSERT EVENTs it doesn't add the newly inserted datafiles.
The problem is that Impala misuses Sets.difference(set1, set2). From the API
doc at
[https://guava.dev/releases/28.2-jre/api/docs/com/google/common/collect/Sets.html#difference-java.util.Set-java.util.Set-]
"The returned set contains all elements that are contained by {{set1}} and not
contained by {{set2}}. {{set2}} may also contain elements not present in
{{set1}}; these are simply ignored."
So the name "difference" is a bit misleading, its rather a subtraction between
set1 and set2.
Unfortunately Impala passes the parameters in wrong order:
Sets.difference(beforeInsert, afterInsert):
[https://github.com/apache/impala/blob/4cb3c3556e77ee24003383155ca5e1b70be4db6e/fe/src/main/java/org/apache/impala/service/CatalogOpExecutor.java#L4581]
So the result will be always empty.
There's another problem with INSERT OVERWRITEs, in that case we never fill the
data files of the insert event.
> Insert events doesn't contain the inserted data files
> -----------------------------------------------------
>
> Key: IMPALA-10135
> URL: https://issues.apache.org/jira/browse/IMPALA-10135
> Project: IMPALA
> Issue Type: Bug
> Reporter: Zoltán Borók-Nagy
> Priority: Major
>
> When Impala generates INSERT EVENTs it doesn't add the newly inserted
> datafiles.
> The problem is that Impala misuses Sets.difference(set1, set2). From the API
> doc at
> [https://guava.dev/releases/28.2-jre/api/docs/com/google/common/collect/Sets.html#difference-java.util.Set-java.util.Set-]
> "The returned set contains all elements that are contained by {{set1}} and
> not contained by {{set2}}. {{set2}} may also contain elements not present in
> {{set1}}; these are simply ignored."
> So the name "difference" is a bit misleading, it's rather a subtraction
> between set1 and set2.
> Unfortunately Impala passes the parameters in wrong order:
> Sets.difference(beforeInsert, afterInsert):
> [https://github.com/apache/impala/blob/4cb3c3556e77ee24003383155ca5e1b70be4db6e/fe/src/main/java/org/apache/impala/service/CatalogOpExecutor.java#L4581]
> So the result will be always empty.
> There's another problem with INSERT OVERWRITEs, in that case we never fill
> the data files of the insert event.
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