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Mike Drob commented on HBASE-18555: ----------------------------------- Ah, ok, I see now. With putIfAbsent the code would have an extra allocation and gc when the family already exists. That's good enough for me. > 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 > Attachments: HBASE-18555.master.000.patch > > > 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) -- This message was sent by Atlassian JIRA (v6.4.14#64029)