hbase-issues mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Xiang Li (JIRA)" <j...@apache.org>
Subject [jira] [Updated] (HBASE-19917) Improve RSGroupBasedLoadBalancer#filterServers() to be more efficient
Date Fri, 02 Feb 2018 08:21:00 GMT

     [ https://issues.apache.org/jira/browse/HBASE-19917?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Xiang Li updated HBASE-19917:
-----------------------------
    Description: 
{code:title=hbase-rsgroup/src/main/java/org/apache/hadoop/hbase/rsgroup/RSGroupBasedLoadBalancer.java|borderStyle=solid}
private List<ServerName> filterServers(Collection<Address> servers,
    Collection<ServerName> onlineServers) {
  ArrayList<ServerName> finalList = new ArrayList<ServerName>();
  for (Address server : servers) {
    for(ServerName curr: onlineServers) {
      if(curr.getAddress().equals(server)) {
        finalList.add(curr);
      }
    }
  }
  return finalList;
}
{code}

filterServers is to return the union of servers and onlineServers. The current implementation
has time complexity as O(m * n) (2 loops), could be in O(m + n) if HashSet is used. The trade-off
is space complexity is increased.

Another point which could be improved: filterServers() is only called in filterOfflineServers().
filterOfflineServers calls filterServers(Set, List). The current filterServers(Collection,
Collection) seems could be improved.

  was:
{code:title=hbase-rsgroup/src/main/java/org/apache/hadoop/hbase/rsgroup/RSGroupBasedLoadBalancer.java|borderStyle=solid}
private List<ServerName> filterServers(Collection<Address> servers,
    Collection<ServerName> onlineServers) {
  ArrayList<ServerName> finalList = new ArrayList<ServerName>();
  for (Address server : servers) {
    for(ServerName curr: onlineServers) {
      if(curr.getAddress().equals(server)) {
        finalList.add(curr);
      }
    }
  }
  return finalList;
}
{code}

filterServers is to return the union of servers and onlineServers. The current implementation
has time complexity as O(m*n) (2 loops), could be in O(m + n) if HashSet is used. The trade-off
is space complexity is increased.

Another point which could be improved: filterServers() is only called in filterOfflineServers().
filterOfflineServers calls filterServers(Set, List). The current filterServers(Collection,
Collection) seems could be improved.


> Improve RSGroupBasedLoadBalancer#filterServers() to be more efficient
> ---------------------------------------------------------------------
>
>                 Key: HBASE-19917
>                 URL: https://issues.apache.org/jira/browse/HBASE-19917
>             Project: HBase
>          Issue Type: Improvement
>          Components: rsgroup
>            Reporter: Xiang Li
>            Assignee: Xiang Li
>            Priority: Minor
>
> {code:title=hbase-rsgroup/src/main/java/org/apache/hadoop/hbase/rsgroup/RSGroupBasedLoadBalancer.java|borderStyle=solid}
> private List<ServerName> filterServers(Collection<Address> servers,
>     Collection<ServerName> onlineServers) {
>   ArrayList<ServerName> finalList = new ArrayList<ServerName>();
>   for (Address server : servers) {
>     for(ServerName curr: onlineServers) {
>       if(curr.getAddress().equals(server)) {
>         finalList.add(curr);
>       }
>     }
>   }
>   return finalList;
> }
> {code}
> filterServers is to return the union of servers and onlineServers. The current implementation
has time complexity as O(m * n) (2 loops), could be in O(m + n) if HashSet is used. The trade-off
is space complexity is increased.
> Another point which could be improved: filterServers() is only called in filterOfflineServers().
filterOfflineServers calls filterServers(Set, List). The current filterServers(Collection,
Collection) seems could be improved.



--
This message was sent by Atlassian JIRA
(v7.6.3#76005)

Mime
View raw message