[jira] [Comment Edited] (HBASE-12431) Use of getColumnLatestCell(byte[], int, int, byte[], int, int) is Not Thread Safe

["stack (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/HBASE-12431?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14233524#comment-14233524 ] 

stack edited comment on HBASE-12431 at 12/3/14 9:17 PM:
--------------------------------------------------------

Changed my mind.  Removing my +1.

Can the allocation of the thread local be lazily done?

Or, can this buffer not just be a local allocation?  We are 'saving' on allocating each time through a rarely used code path.


was (Author: stack):
+1

> Use of getColumnLatestCell(byte[], int, int, byte[], int, int) is Not Thread Safe
> ---------------------------------------------------------------------------------
>
>                 Key: HBASE-12431
>                 URL: https://issues.apache.org/jira/browse/HBASE-12431
>             Project: HBase
>          Issue Type: Bug
>          Components: Client
>    Affects Versions: 0.98.1
>            Reporter: Jonathan Jarvis
>            Assignee: Jingcheng Du
>             Fix For: 1.0.0, 2.0.0, 0.98.9
>
>         Attachments: HBASE-12431-V2.diff, HBASE-12431-V3.diff, HBASE-12431.diff
>
>
> Result declares that it is NOT THREAD SAFE at the top of the source code, but one would assume that refers to many different threads accessing the same Result object. I've run into an issue when I have several different threads accessing their own Result object that runs into an issue because of use of common static member variable.
> I noticed the problem when I switched from:
> getColumnLatestCell(byte[], byte[]) to
> getColumnLatestCell(byte[], int, int, byte[], int, int)
> These methods call different binarySearch methods, the latter invoking:
> protected int  binarySearch(final Cell [] kvs,
> 309      final byte [] family, final int foffset, final int flength,
> 310      final byte [] qualifier, final int qoffset, final int qlength) {
> This method utilizes a private static member variable called "buffer"
> If more than one thread is utilizing "buffer" you'll see unpredictable behavior unless you synchronize(Result.class) {}.
> If buffer is to remain a static variable, I would recommend changing it to a ThreadLocal<byte[]> instead.



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