lucene-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Jason Rutherglen (JIRA)" <j...@apache.org>
Subject [jira] Commented: (LUCENE-2573) Tiered flushing of DWPTs by RAM with low/high water marks
Date Fri, 24 Sep 2010 00:44:35 GMT

    [ https://issues.apache.org/jira/browse/LUCENE-2573?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12914296#action_12914296
] 

Jason Rutherglen commented on LUCENE-2573:
------------------------------------------

I was hoping something clever would come to me about how to unit test this, nothing has. 
We can do the slowdown of writes to the file(s) via a Thread.sleep, however this will only
emulate a real file system in RAM, what then?  I thought about testing the percentage however
is it going to be exact?  We could test a percentage range of each of the segments flushed?
 I guess I just need to run the all of the unit tests, however some of those will fail because
deletes aren't working properly yet.  

> Tiered flushing of DWPTs by RAM with low/high water marks
> ---------------------------------------------------------
>
>                 Key: LUCENE-2573
>                 URL: https://issues.apache.org/jira/browse/LUCENE-2573
>             Project: Lucene - Java
>          Issue Type: Improvement
>          Components: Index
>            Reporter: Michael Busch
>            Assignee: Michael Busch
>            Priority: Minor
>             Fix For: Realtime Branch
>
>         Attachments: LUCENE-2573.patch, LUCENE-2573.patch, LUCENE-2573.patch
>
>
> Now that we have DocumentsWriterPerThreads we need to track total consumed RAM across
all DWPTs.
> A flushing strategy idea that was discussed in LUCENE-2324 was to use a tiered approach:
 
> - Flush the first DWPT at a low water mark (e.g. at 90% of allowed RAM)
> - Flush all DWPTs at a high water mark (e.g. at 110%)
> - Use linear steps in between high and low watermark:  E.g. when 5 DWPTs are used, flush
at 90%, 95%, 100%, 105% and 110%.
> Should we allow the user to configure the low and high water mark values explicitly using
total values (e.g. low water mark at 120MB, high water mark at 140MB)?  Or shall we keep for
simplicity the single setRAMBufferSizeMB() config method and use something like 90% and 110%
for the water marks?

-- 
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.


---------------------------------------------------------------------
To unsubscribe, e-mail: dev-unsubscribe@lucene.apache.org
For additional commands, e-mail: dev-help@lucene.apache.org


Mime
View raw message