[
https://issues.apache.org/jira/browse/LUCENE-2793?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13045354#comment-13045354
]
Michael McCandless commented on LUCENE-2793:
--------------------------------------------
Patch looks great! Comments:
* I think IOCtx should have ctor taking only OneMerge, which would
set the OneMerge and set the context as Merge?
* Likewise, a ctor taking a SegmentInfo to mean context = Flush?
* And finally a default ctor that maps to Other (or Default or
Unknown or Unspecified or something)
* You don't need to create the IOCtx in IW.maybeMerge?
* Maybe we want a "readOnce" boolean in IOCtx? When we read del
docs, norms, terms index, doc values, segments file /
segments.gen, we would set this? (And UnixDir would send eg
NO_REUSE down to the OS).
* I think we'll need a NativeMMapDir as well as NativeDir (or
NativeUnix/WindowsDir), because mmap can also take flags giving
hints about access patterns. I'll open a new issue...
* Why does SegmentCoreReaders hang onto the IOCtx? Seems like
classes shouldn't hang onto it... (also: PreFlexFields).
* Hmm.... does createOutput even need an IOCtx...? What would a dir
do with this? I suppose if it's a merge and we had io
prioritization (someday) we could set lower prio... OK let's keep
it.
* I think Codec.fieldsProducer/Consumer should take an IOCtx?
* Still need to fix IW's ReaderPool to key off of IOCtx.Context plus
the info. Maybe put a // nocommit in there so we remember...?
Eg, where you commented out the readBufferSize = ... inside
ReaderPool.get is a good place.
> Directory createOutput and openInput should take an IOContext
> -------------------------------------------------------------
>
> Key: LUCENE-2793
> URL: https://issues.apache.org/jira/browse/LUCENE-2793
> Project: Lucene - Java
> Issue Type: Improvement
> Components: core/store
> Reporter: Michael McCandless
> Assignee: Varun Thacker
> Labels: gsoc2011, lucene-gsoc-11, mentor
> Attachments: LUCENE-2793.patch, LUCENE-2793.patch, LUCENE-2793.patch,
> LUCENE-2793.patch, LUCENE-2793.patch, LUCENE-2793.patch
>
>
> Today for merging we pass down a larger readBufferSize than for searching
> because we get better performance.
> I think we should generalize this to a class (IOContext), which would hold
> the buffer size, but then could hold other flags like DIRECT (bypass OS's
> buffer cache), SEQUENTIAL, etc.
> Then, we can make the DirectIOLinuxDirectory fully usable because we would
> only use DIRECT/SEQUENTIAL during merging.
> This will require fixing how IW pools readers, so that a reader opened for
> merging is not then used for searching, and vice/versa. Really, it's only
> all the open file handles that need to be different -- we could in theory
> share del docs, norms, etc, if that were somehow possible.
--
This message is automatically generated by JIRA.
For more information on JIRA, see: http://www.atlassian.com/software/jira
---------------------------------------------------------------------
To unsubscribe, e-mail: dev-unsubscr...@lucene.apache.org
For additional commands, e-mail: dev-h...@lucene.apache.org
