Github user mridulm commented on a diff in the pull request:

    https://github.com/apache/spark/pull/16844#discussion_r100473254
  
    --- Diff: 
core/src/main/java/org/apache/spark/unsafe/map/BytesToBytesMap.java ---
    @@ -695,11 +690,16 @@ public boolean append(Object kbase, long koff, int 
klen, Object vbase, long voff
           assert (vlen % 8 == 0);
           assert (longArray != null);
     
    -      if (numKeys == MAX_CAPACITY
    -        // The map could be reused from last spill (because of no enough 
memory to grow),
    -        // then we don't try to grow again if hit the `growthThreshold`.
    -        || !canGrowArray && numKeys > growthThreshold) {
    -        return false;
    +      if (numKeys >= growthThreshold) {
    +        if (longArray.size() / 2 == MAX_CAPACITY) {
    --- End diff --
    
    @davies is correct; but it is a slightly unintuitive way to write the 
condition.
    
    ```
    val currentSize = longArray.size()
    val newSize = currentSize * 2
    val currentKeysLen = currentSize / 2
    val newKeysLen = currentKeysLen * 2
    
    if (newKeysLen > MAX_CAPACITY) then fail.
    that is  if (currentKeysLen == MAX_CAPACITY) then fail // Since we allow 
only power of 2's for all these values.
    that is  if (longArray.size() / 2 == MAX_CAPACITY)
    
    ```
    
    Particularly given its location (in append as opposed to grow), it serves 
to be a bit more confusing that expected.


---
If your project is set up for it, you can reply to this email and have your
reply appear on GitHub as well. If your project does not have this feature
enabled and wishes so, or if the feature is enabled but not working, please
contact infrastructure at infrastruct...@apache.org or file a JIRA ticket
with INFRA.
---

---------------------------------------------------------------------
To unsubscribe, e-mail: reviews-unsubscr...@spark.apache.org
For additional commands, e-mail: reviews-h...@spark.apache.org

Reply via email to