You are viewing a plain text version of this content. The canonical link for it is here.
Posted to issues@arrow.apache.org by "Eric Erhardt (JIRA)" <ji...@apache.org> on 2019/02/11 16:11:00 UTC
[jira] [Assigned] (ARROW-4503) [C#] ArrowStreamReader allocates and
copies data excessively
[ https://issues.apache.org/jira/browse/ARROW-4503?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Eric Erhardt reassigned ARROW-4503:
-----------------------------------
Assignee: Eric Erhardt
> [C#] ArrowStreamReader allocates and copies data excessively
> ------------------------------------------------------------
>
> Key: ARROW-4503
> URL: https://issues.apache.org/jira/browse/ARROW-4503
> Project: Apache Arrow
> Issue Type: Improvement
> Components: C#
> Reporter: Eric Erhardt
> Assignee: Eric Erhardt
> Priority: Major
> Labels: performance
> Original Estimate: 48h
> Remaining Estimate: 48h
>
> When reading `RecordBatch` instances using the `ArrowStreamReader` class, it is currently allocating and copying memory 3 times for the data.
> # It is allocating memory in order to [read the data from the Stream|https://github.com/apache/arrow/blob/044b418fa108a57f0b4e2e887546cc3e68271397/csharp/src/Apache.Arrow/Ipc/ArrowStreamReader.cs#L72-L74], and then reading from the Stream. (This should be the only allocation that is necessary.)
> # It then [creates a new `ArrowBuffer.Builder`|https://github.com/apache/arrow/blob/044b418fa108a57f0b4e2e887546cc3e68271397/csharp/src/Apache.Arrow/Ipc/ArrowStreamReader.cs#L227-L228], which allocates another `byte[]`, and calls `Append` on it, which copies the values to the new `byte[]`.
> # Finally, it then calls `.Build()` on the `ArrowBuffer.Builder`, which [allocates memory from the MemoryPool, and then copies the intermediate buffer|https://github.com/apache/arrow/blob/044b418fa108a57f0b4e2e887546cc3e68271397/csharp/src/Apache.Arrow/ArrowBuffer.Builder.cs#L112-L121] into it.
>
> We should reduce this overhead to only allocating a single time (from the MemoryPool), and not copying the data more times than necessary.
--
This message was sent by Atlassian JIRA
(v7.6.3#76005)