phoenix-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "James Taylor (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (PHOENIX-1779) Parallelize fetching of next batch of records for scans corresponding to queries with no order by
Date Tue, 07 Apr 2015 15:59:12 GMT

    [ https://issues.apache.org/jira/browse/PHOENIX-1779?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14483406#comment-14483406
] 

James Taylor commented on PHOENIX-1779:
---------------------------------------

Impressive! Nice work.


> Parallelize fetching of next batch of records for scans corresponding to queries with
no order by 
> --------------------------------------------------------------------------------------------------
>
>                 Key: PHOENIX-1779
>                 URL: https://issues.apache.org/jira/browse/PHOENIX-1779
>             Project: Phoenix
>          Issue Type: Improvement
>            Reporter: Samarth Jain
>            Assignee: Samarth Jain
>         Attachments: wip.patch, wip3.patch, wipwithsplits.patch
>
>
> Today in Phoenix we parallelize the first execution of scans i.e. we load only the first
batch of records up to the scan's cache size in parallel. Loading of subsequent batches of
records in scanners is essentially serial. This could be improved especially for queries,
including the ones with no order by clauses,  that do not need any kind of merge sort on the
client. This could also potentially improve the performance of UPSERT SELECT statements that
load data from one table and insert into another. One such use case being creating immutable
indexes for tables that already have data. It could also potentially improve the performance
of our MapReduce solution for bulk loading data by improving the speed of the loading/mapping
phase. 



--
This message was sent by Atlassian JIRA
(v6.3.4#6332)

Mime
View raw message