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From "John Wang (JIRA)" <j...@apache.org>
Subject [jira] Commented: (LUCENE-2252) stored field retrieve slow
Date Sun, 07 Feb 2010 00:33:28 GMT

    [ https://issues.apache.org/jira/browse/LUCENE-2252?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12830599#action_12830599
] 

John Wang commented on LUCENE-2252:
-----------------------------------

Thanks Uwe for the pointer. Will check that out!

Robert, we can get away with 4 bytes per doc assuming we are not storing 2GB of data per doc.
This memory would be less than the data structure needed to be held in memory for only 1 field
cache entry for sort. I understand it is always better to use less memory, but sometimes we
do have to make trade-off decisions.
But you are right, different applications have different needs/requirements, so having support
for custom segments would be a good thing. e.g. LUCENE-1914

> stored field retrieve slow
> --------------------------
>
>                 Key: LUCENE-2252
>                 URL: https://issues.apache.org/jira/browse/LUCENE-2252
>             Project: Lucene - Java
>          Issue Type: Improvement
>          Components: Store
>    Affects Versions: 3.0
>            Reporter: John Wang
>
> IndexReader.document() on a stored field is rather slow. Did a simple multi-threaded
test and profiled it:
> 40+% time is spent in getting the offset from the index file
> 30+% time is spent in reading the count (e.g. number of fields to load)
> Although I ran it on my lap top where the disk isn't that great, but still seems to be
much room in improvement, e.g. load field index file into memory (for a 5M doc index, the
extra memory footprint is 20MB, peanuts comparing to other stuff being loaded)
> A related note, are there plans to have custom segments as part of flexible indexing
feature?

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