[jira] [Commented] (HBASE-16229) Cleaning up size and heapSize calculation

["Anoop Sam John (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/HBASE-16229?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15376590#comment-15376590 ] 

Anoop Sam John commented on HBASE-16229:
----------------------------------------

This also looks odd
MemstoreCompactor
{code}
private void doCompaction() {

    ImmutableSegment result = SegmentFactory.instance()  // create the scanner
        .createImmutableSegment(
            compactingMemStore.getConfiguration(), compactingMemStore.getComparator(),
            CompactingMemStore.DEEP_OVERHEAD_PER_PIPELINE_ITEM);

    // the compaction processing
    try {
      // Phase I: create the compacted MutableCellSetSegment
      compactSegments(result);
{code}
'result' is created as an ImmutableSegment and we will be adding cells to it.  Within this method, we should have created a new MutableSegment and add to that and finally create an ImmutableSegment around the result. That would have looked clean.

> Cleaning up size and heapSize calculation
> -----------------------------------------
>
>                 Key: HBASE-16229
>                 URL: https://issues.apache.org/jira/browse/HBASE-16229
>             Project: HBase
>          Issue Type: Sub-task
>    Affects Versions: 2.0.0
>            Reporter: Anoop Sam John
>            Assignee: Anoop Sam John
>             Fix For: 2.0.0
>
>
> It is bit ugly now. For eg:
> AbstractMemStore
> {code}
> public final static long FIXED_OVERHEAD = ClassSize.align(
>       ClassSize.OBJECT +
>           (4 * ClassSize.REFERENCE) +
>           (2 * Bytes.SIZEOF_LONG));
>   public final static long DEEP_OVERHEAD = ClassSize.align(FIXED_OVERHEAD +
>       (ClassSize.ATOMIC_LONG + ClassSize.TIMERANGE_TRACKER +
>       ClassSize.CELL_SKIPLIST_SET + ClassSize.CONCURRENT_SKIPLISTMAP));
> {code}
> We include the heap overhead of Segment also here. It will be better the Segment contains its overhead part and the Memstore impl uses the heap size of all of its segments to calculate its size.
> Also this
> {code}
> public long heapSize() {
>     return getActive().getSize();
>   }
> {code}
> HeapSize to consider all segment's size not just active's. I am not able to see an override method in CompactingMemstore.
> This jira tries to solve some of these.
> When we create a Segment, we seems pass some initial heap size value to it. Why?  The segment object internally has to know what is its heap size not like some one else dictate it.
> More to add when doing this cleanup



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