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https://issues.apache.org/jira/browse/HBASE-14873?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15037272#comment-15037272
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Anoop Sam John commented on HBASE-14873:
----------------------------------------
Endianness is considered. We always write data in big endian way irrespective
of the system. Read time also we take care to reverse bytes in case needed.
'Alignment ' - Yes let us check this more.. The unsafe way of reading from on
heap buffers/ byte arrays is there from long time. And we added it for off heap
also recently. We need to check it once.
So my suggestion, let us commit this fix which is fixing a critical issue.
Then we check more on making the Unsafe way of copying really 'safe'
> Problems around BoundedByteBufferPool providing direct buffers
> --------------------------------------------------------------
>
> Key: HBASE-14873
> URL: https://issues.apache.org/jira/browse/HBASE-14873
> Project: HBase
> Issue Type: Bug
> Reporter: Hiroshi Ikeda
> Assignee: Hiroshi Ikeda
> Attachments: HBASE-14873-V2.patch, HBASE-14873.patch,
> HBASE-14873.patch, HBASE-14873.patch
>
>
> HBASE-13819 made BoundedByteBufferPool provide direct buffers.
> See RpcServer.java:
> {code}
> ...
> class Call implements RpcCallContext {
> protected synchronized void setResponse(...) {
> ...
> this.cellBlock = ipcUtil.buildCellBlock(..., reservoir);
> ...
> bc = new BufferChain(..., this.cellBlock);
> if (connection.useWrap) {
> bc = wrapWithSasl(bc);
> }
> ...
> private BufferChain wrapWithSasl(BufferChain bc) throws IOException {
> ...
> byte[] responseBytes = bc.getBytes();
> ...
> {code}
> {{cellBlock}} is expected to be a direct buffer retrieved from {{reservoir}}
> (but not always), and {{bc}} may be composed of both direct and non-direct
> buffers.
> And then, see BufferChain.java:
> {code}
> byte [] getBytes() {
> ...
> for (ByteBuffer bb: this.buffers) {
> System.arraycopy(bb.array(), ...);
> {code}
> A direct buffer doesn't give its array, and will throw
> UnsupportedOperationException.
> Another problem; {{cellBlock}} is allowed to be a non-direct buffer, and
> after use it will be put to {{reservoir}}, mixing direct and non-direct
> buffers in the pool.
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