hi
Is there any  design document on this aspect (sorting algorithm off mmap)?


 
---Original---
From: "Uwe Schindler [via Lucene]"<ml+s472066n4340659...@n3.nabble.com>
Date: 2017/6/15 14:39:30
To: "wangqinghuan"<1095193...@qq.com>;
Subject: RE: Would docvalues be loaded into jvm?


 Hi 

It works directly off  the mmapped files. It is not fully loaded into heap, 
only some small control structures are allocated on heap. During sorting the 
TopDocsCollector uses the memory mapped structures to uncompress and lookup the 
sort values. 

Uwe 

----- 
Uwe Schindler 
Achterdiek 19, D-28357 Bremen 
http://www.thetaphi.de
eMail: [hidden email] 

> -----Original Message----- 
> From: wangqinghuan [mailto:[hidden email]] 
> Sent: Thursday, June 15, 2017 4:36 AM 
> To: [hidden email] 
> Subject: Would docvalues be loaded into jvm? 
>  
> hi 
> I know that data is written into disk with the style of column-store if I 
> enable doc-values for certain field. 
> But I don't understand why sorting with docvalues doesn't increase the load 
> of jvm. whatever sorting algorithm , data would be loaded into  jvm to sort. 
> This should be a high load for jvm when I sort all index  , but  no change 
> for jvm in fact.  How does lucene sort with docvalues ? Can sort algorithm 
> work directly based on the file (Mmap) ? 
>  
>  
>  
> -- 
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> Sent from the Lucene - General mailing list archive at Nabble.com. 

 
 
 
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