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From "Xiang Li (JIRA)" <j...@apache.org>
Subject [jira] [Updated] (HBASE-18555) Remove redundant familyMap.put() from Put#addColumn() and addImmutable()
Date Thu, 10 Aug 2017 16:04:00 GMT

     [ https://issues.apache.org/jira/browse/HBASE-18555?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Xiang Li updated HBASE-18555:
-----------------------------
    Description: 
In Put#addColumn() and addImmutable(), after getting the cell list of the given family and
add the cell into the list, the code puts (key=family, value=list) into familyMap.

In addColumn(), it is like
{code}
    List<Cell> list = getCellList(family);
    KeyValue kv = createPutKeyValue(family, qualifier, ts, value);
    list.add(kv);
    familyMap.put(CellUtil.cloneFamily(kv), list); // <-- here
    return this;
{code}

In addImmutable(), it is like
{code}
    List<Cell> list = getCellList(family);
    KeyValue kv = createPutKeyValue(family, qualifier, ts, value, tag);
    list.add(kv);
    familyMap.put(family, list); // <-- here
    return this;
{code}

I think those put() for Map only take effect when getCellList(family) returns a new allocated
ArrayList. When the list for a family already exist, put() for Map will update the value to
the reference of the list, but actually, the reference of the list is not changed.

Those put() do not do any harm in terms of the correctness when they are here. But it could
be removed to improve the performance. familyMap searches for key and set the new value and
return the old value. Those operation take some time but actually are not needed. 

The put() could be moved into Mutation#getCellList(family)

  was:
In Put#addColumn() and addImmutable(), after getting cell list of the given family and add
the cell into the list, the code will put (key=family, value=list) into family map.

In addColumn(), it is like
{code}
    List<Cell> list = getCellList(family);
    KeyValue kv = createPutKeyValue(family, qualifier, ts, value);
    list.add(kv);
    familyMap.put(CellUtil.cloneFamily(kv), list); // <-- here
    return this;
{code}

In addImmutable(), it is like
{code}
    List<Cell> list = getCellList(family);
    KeyValue kv = createPutKeyValue(family, qualifier, ts, value, tag);
    list.add(kv);
    familyMap.put(family, list); // <-- here
    return this;
{code}

I think put() for Map only take effect when getCellList(family) returns a new allocated ArrayList.
When the list for a family already exist, put() for Map will update the value to the reference
of the list, but actually, the reference of the list is not changed.

Those put() do not do any harm in terms of the correctness when they are here. But it could
be removed to improve the performance, as familyMap is a TreeMap, in put(), it searches for
key and set the new value and return the old value. Those operation take some time but actually
are not needed. 

The put() could be moved into Mutation#getCellList(family)


> Remove redundant familyMap.put() from Put#addColumn() and addImmutable()
> ------------------------------------------------------------------------
>
>                 Key: HBASE-18555
>                 URL: https://issues.apache.org/jira/browse/HBASE-18555
>             Project: HBase
>          Issue Type: Improvement
>          Components: Client
>            Reporter: Xiang Li
>            Assignee: Xiang Li
>            Priority: Minor
>
> In Put#addColumn() and addImmutable(), after getting the cell list of the given family
and add the cell into the list, the code puts (key=family, value=list) into familyMap.
> In addColumn(), it is like
> {code}
>     List<Cell> list = getCellList(family);
>     KeyValue kv = createPutKeyValue(family, qualifier, ts, value);
>     list.add(kv);
>     familyMap.put(CellUtil.cloneFamily(kv), list); // <-- here
>     return this;
> {code}
> In addImmutable(), it is like
> {code}
>     List<Cell> list = getCellList(family);
>     KeyValue kv = createPutKeyValue(family, qualifier, ts, value, tag);
>     list.add(kv);
>     familyMap.put(family, list); // <-- here
>     return this;
> {code}
> I think those put() for Map only take effect when getCellList(family) returns a new allocated
ArrayList. When the list for a family already exist, put() for Map will update the value to
the reference of the list, but actually, the reference of the list is not changed.
> Those put() do not do any harm in terms of the correctness when they are here. But it
could be removed to improve the performance. familyMap searches for key and set the new value
and return the old value. Those operation take some time but actually are not needed. 
> The put() could be moved into Mutation#getCellList(family)



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