[
https://issues.apache.org/jira/browse/HBASE-20197?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16401125#comment-16401125
]
BELUGA BEHR edited comment on HBASE-20197 at 3/15/18 9:22 PM:
--------------------------------------------------------------
[~anoop.hbase] I have attached another patch [^HBASE-20197.5.patch] which uses
{{ByteBufferUtils}}. You all can pick, though I personally prefer
[^HBASE-20197.4.patch] for KISS and future-proofing. :)
was (Author: belugabehr):
[~anoop.hbase] I have attached another patch [^HBASE-20197.5.patch] which uses
{{ByteBufferUtils}}. You all can pick. :)
> Review of ByteBufferWriterOutputStream.java
> -------------------------------------------
>
> Key: HBASE-20197
> URL: https://issues.apache.org/jira/browse/HBASE-20197
> Project: HBase
> Issue Type: Improvement
> Components: hbase
> Affects Versions: 2.0.0
> Reporter: BELUGA BEHR
> Assignee: BELUGA BEHR
> Priority: Minor
> Attachments: HBASE-20197.1.patch, HBASE-20197.2.patch,
> HBASE-20197.3.patch, HBASE-20197.4.patch, HBASE-20197.5.patch
>
>
> In looking at this class, two things caught my eye.
> # Default buffer size of 4K
> # Re-sizing of buffer on demand
>
> Java's {{BufferedOutputStream}} uses an internal buffer size of 8K on modern
> JVMs. This is due to various bench-marking that showed optimal performance
> at this level.
> The Re-sizing buffer looks a bit "unsafe":
>
> {code:java}
> public void write(ByteBuffer b, int off, int len) throws IOException {
> byte[] buf = null;
> if (len > TEMP_BUF_LENGTH) {
> buf = new byte[len];
> } else {
> if (this.tempBuf == null) {
> this.tempBuf = new byte[TEMP_BUF_LENGTH];
> }
> buf = this.tempBuf;
> }
> ...
> }
> {code}
> If this method gets one call with a 'len' of 4000, then 4001, then 4002, then
> 4003, etc. then the 'tempBuf' will be re-created many times. Also, it seems
> unsafe to create a buffer as large as the 'len' input. This could
> theoretically lead to an internal buffer of 2GB for each instance of this
> class.
> I propose:
> # Increase the default buffer size to 8K
> # Create the buffer once and chunk the output instead of loading data into a
> single array and writing it to the output stream.
>
--
This message was sent by Atlassian JIRA
(v7.6.3#76005)
