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https://issues.apache.org/jira/browse/NIFI-4794?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16341181#comment-16341181
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ASF GitHub Bot commented on NIFI-4794:
--------------------------------------
GitHub user markap14 opened a pull request:
https://github.com/apache/nifi/pull/2437
NIFI-4794: Updated event writers to avoid creating a lot of byte[] by…
… reusing buffers. Also removed synchronization on EventWriter when rolling
over the writer and just moved the writing of the header to happen before
making the writer available to any other threads. This reduces thread
contention during rollover.
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You can merge this pull request into a Git repository by running:
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Alternatively you can review and apply these changes as the patch at:
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This closes #2437
----
commit 3bbd64bfebe81cb099a4b8017d839e591b3d9bc7
Author: Mark Payne <markap14@...>
Date: 2018-01-25T17:16:56Z
NIFI-4794: Updated event writers to avoid creating a lot of byte[] by
reusing buffers. Also removed synchronization on EventWriter when rolling over
the writer and just moved the writing of the header to happen before making the
writer available to any other threads. This reduces thread contention during
rollover.
----
> Improve Garbage Collection required by Provenance Repository
> ------------------------------------------------------------
>
> Key: NIFI-4794
> URL: https://issues.apache.org/jira/browse/NIFI-4794
> Project: Apache NiFi
> Issue Type: Improvement
> Components: Core Framework
> Reporter: Mark Payne
> Assignee: Mark Payne
> Priority: Major
>
> The EventIdFirstSchemaRecordWriter that is used by the provenance repository
> has a writeRecord(ProvenanceEventRecord) method. Within this method, it
> serializes the given record into a byte array by serializing to a
> ByteArrayOutputStream (after wrapping the BAOS in a DataOutputStream). Once
> this is done, it calls toByteArray() on that BAOS so that it can write the
> byte[] directly to another OutputStream.
> This can create a rather large amount of garbage to be collected. We can
> improve this significantly:
> # Instead of creating a new ByteArrayOutputStream each time, create a pool
> of them. This avoids constantly having to garbage collect them.
> # If said BAOS grows beyond a certain size, we should not return it to the
> pool because we don't want to keep a huge impact on the heap.
> # Instead of wrapping the BAOS in a new DataOutputStream, the
> DataOutputStream should be pooled/recycled as well. Since it must create an
> internal byte[] for the writeUTF method, this can save a significant amount
> of garbage.
> # Avoid calling ByteArrayOutputStream.toByteArray(). We can instead just use
> ByteArrayOutputStream.writeTo(OutputStream). This avoids both allocating that
> new array/copying the data, and the GC overhead.
>
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