[HBASE-21640] Remove the TODO when increment zero

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 3.0.0-alpha-1, 2.2.0, 2.1.2, 2.0.4
• Assignee: Guanghao Zhang
• Reporter: Guanghao Zhang
• Created: 25/Dec/18 09:33
• Updated: 27/Dec/18 12:38
• Resolved: 26/Dec/18 14:10

Description

 

// If delta amount to apply is 0, don't write WAL or MemStore.
long deltaAmount = getLongValue(delta);
// TODO: Does zero value mean reset Cell? For example, the ttl.
apply = deltaAmount != 0;

This is an optimization when increment 0. But it introduced some new problems.

1.As the TODO said, Does zero value mean reset ttl?

2.HBASE-17318 have to introduce a new variable "firstWrite" because it don't apply 0.

3. There is a coprocessor method postMutationBeforeWAL to return a new cell. But it may be not applied.

 

// Give coprocessors a chance to update the new cell
if (coprocessorHost != null) {
  newCell =
      coprocessorHost.postMutationBeforeWAL(mutationType, mutation, currentValue, newCell);
}
// If apply, we need to update memstore/WAL with new value; add it toApply.
if (apply || firstWrite) {
  toApply.add(newCell);
}

 

So my proposal is remove this optimization. Any suggestions are welcomed.

 

 

 

 

 

Issue Links

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