[
https://issues.apache.org/jira/browse/LUCENE-5722?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14014958#comment-14014958
]
Uwe Schindler commented on LUCENE-5722:
---------------------------------------
bq. I was just responding to the first comment! I do not really want an assert,
as this method Shoukd be considered hot (its the point of the issue) and assert
is not free.
OK :-) I just wanted to point out that we have no 100% safety if you seek out
of slice for the single buffer case.
I was just afraid that you were complaining about collecting ideas for
optimizing the multi-buffer seek (see above). I am not sure if my idea helps or
is risky at all, we should just try it out.
> Speed up MMapDirectory.seek()
> -----------------------------
>
> Key: LUCENE-5722
> URL: https://issues.apache.org/jira/browse/LUCENE-5722
> Project: Lucene - Core
> Issue Type: Bug
> Reporter: Robert Muir
> Attachments: LUCENE-5722.patch
>
>
> For traditional lucene access which is mostly sequential, occasional
> advance(), I think this method gets drowned out in noise.
> But for access like docvalues, its important. Unfortunately seek() is complex
> today because of mapping multiple buffers.
> However, the very common case is that only one map is used for a given clone
> or slice.
> When there is the possibility to use only a single mapped buffer, we should
> instead take advantage of ByteBuffer.slice(), which will adjust the internal
> mmap address and remove the offset calculation. furthermore we don't need the
> shift/mask or even the negative check, as they are then all handled with the
> ByteBuffer api: seek is a one-liner (with try/catch of course to convert
> exceptions).
> This makes docvalues access 20% faster, I havent tested conjunctions or
> anyhting like that.
--
This message was sent by Atlassian JIRA
(v6.2#6252)
---------------------------------------------------------------------
To unsubscribe, e-mail: [email protected]
For additional commands, e-mail: [email protected]
