Vladimir Rodionov created HBASE-15493:
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Summary: Default ArrayList size may not be optimal for Mutation
Key: HBASE-15493
URL: https://issues.apache.org/jira/browse/HBASE-15493
Project: HBase
Issue Type: Improvement
Components: Client, regionserver
Affects Versions: 2.0.0
Reporter: Vladimir Rodionov
Assignee: Vladimir Rodionov
Fix For: 2.0.0
{code}
List<Cell> getCellList(byte[] family) {
List<Cell> list = this.familyMap.get(family);
if (list == null) {
list = new ArrayList<Cell>();
}
return list;
}
{code}
Creates list of size 10, this is up to 80 bytes per column family in mutation
object.
Suggested:
{code}
List<Cell> getCellList(byte[] family) {
List<Cell> list = this.familyMap.get(family);
if (list == null) {
list = new ArrayList<Cell>(CELL_LIST_INITIAL_CAPACITY);
}
return list;
}
{code}
CELL_LIST_INITIAL_CAPACITY = 2 in the patch, this is debatable. For mutation
where every CF has 1 cell, this gives decent reduction in memory allocation
rate in both client and server during write workload. ~2%, not a big number,
but as I said, already, memory optimization will include many small steps.
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