[HBASE-9521] clean clearBufferOnFail behavior and deprecate it

• Type: Bug
• Status: Closed
• Priority: Critical
• Resolution: Fixed
• Affects Version/s: 0.98.0, 0.96.0
• Fix Version/s: 0.98.0, 0.96.0
• Component/s: Client
• Hadoop Flags: Reviewed
• Assignee: Nicolas Liochon
• Reporter: Nicolas Liochon
• Created: 12/Sep/13 09:24
• Updated: 20/Nov/15 11:56
• Resolved: 16/Sep/13 20:08

Description

The behavior with clearBufferOnFail is very fishy.

 /**
   * When you turn {@link #autoFlush} off, you should also consider the
   * {@link #clearBufferOnFail} option. By default, asynchronous {@link Put}
   * requests will be retried on failure until successful. However, this can
   * pollute the writeBuffer and slow down batching performance. Additionally,
   * you may want to issue a number of Put requests and call
   * {@link #flushCommits()} as a barrier. In both use cases, consider setting
   * clearBufferOnFail to true to erase the buffer after {@link #flushCommits()}
   * has been called, regardless of success.
   *
   * @param autoFlush
   *          Whether or not to enable 'auto-flush'.
   * @param clearBufferOnFail
   *          Whether to keep Put failures in the writeBuffer
   * @see #flushCommits
   */
  public void setAutoFlush(boolean autoFlush, boolean clearBufferOnFail) {
    this.autoFlush = autoFlush;
    this.clearBufferOnFail = autoFlush || clearBufferOnFail;  <============ yo man
  }

  public void setAutoFlush(boolean autoFlush) {
    setAutoFlush(autoFlush, autoFlush); <============ more yo
  }

So by default, a HTable has

• autoflush == true
• clearBufferOnFail == true

BUT, if you call setAutoFlush(false), you have

• autoflush == false
• clearBufferOnFail == false

So:

• you're setting two parameters instead of only one, without being told so.
• a side effect is that failed operations will be tried twice:
• one in the standard process
• one in the table close, as we're flushing the buffer again

I would like to:

• deprecate clearBufferOnFail.
• deprecate setAutoFlush(boolean), to make things clear about what we're doing.