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https://issues.apache.org/jira/browse/ARROW-6896?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16952555#comment-16952555
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Liya Fan commented on ARROW-6896:
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[~jnadeau] Sure. Agreed with you.
This issue fixes the problem of sharing vectors between VectorSchemaRoots. If
this sounds good, would you please take a look at the PR?
> [Java] Vector schema root should not share vectors
> --------------------------------------------------
>
> Key: ARROW-6896
> URL: https://issues.apache.org/jira/browse/ARROW-6896
> Project: Apache Arrow
> Issue Type: Bug
> Components: Java
> Reporter: Liya Fan
> Assignee: Liya Fan
> Priority: Major
> Labels: pull-request-available
> Time Spent: 0.5h
> Remaining Estimate: 0h
>
> Vector schema root should not share vectors. Otherwise, unexpectd behavior
> would happen.
> Please note that VectorSchemaRoot is not just a container for vectors, it is
> also a resource (it implements the AutoClosable interface), and it manages
> the life cycle of its inner vectors.
> When two VectorSchemaRoots share vectors, something unexpected may happen.
> Consider the following scenario, which is frequently encountered in a SQL
> engine.
> 1. We create a batch:
> VectorSchemaRoot oldBatch = ...
> 2. We add a vector to it, which results in a new batch
> VectorSchemaRoot newBatch = oldBatch.addVector(vector);
> 3. We are done with the old batch, and release the resource
> oldBatch.close();
> 4. We continue to use the new batch, but gets an exception, because some
> inner vectors have been released by the old batch.
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