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From "Shai Erera (JIRA)" <>
Subject [jira] Updated: (LUCENE-2455) Some house cleaning in addIndexes*
Date Sat, 22 May 2010 06:15:15 GMT


Shai Erera updated LUCENE-2455:

    Attachment: LUCENE-2455_3x.patch

Patch includes the following:
* addIndexesNoOpt renamed to addIndexes2 for now, until we resolve the failing test (see below).
I'll remove it and fix jdocs accordingly afterwards.
* addIndexes(Dir...) implements the simple file copy strategy.
* Tests updated accordingly.
* Some minor changes to CompoundFileReader and IndexFileNames, as discussed before.

All tests pass except for TestIndexWriter.testAddIndexesWithThreads. I've debugged it, but
cannot find the reason. addIndexes copies all segments, before it adds them to the writer's
segmentInfos. Maybe I need to use start/commit transaction on that part only, to lock all
ops? I don't see why, but maybe?

Also, TestAddIndexes.testWithPendingDeletes2() (and some others) fail before I added a call
to flush to addIndexes. It seems that w/o it, existing buffered deleted docs are ignored after
addIndexes returns (even when no multi-threading is involved). Can someone please confirm

Also, I cannot simplify PPP (to remove DirPP) because we kept addIndexes(Reader...). It's
an annoyance if you don't call this method (need to return a DirPP for the target Dir always
- if you want to use it), but maybe not so bad ...

> Some house cleaning in addIndexes*
> ----------------------------------
>                 Key: LUCENE-2455
>                 URL:
>             Project: Lucene - Java
>          Issue Type: Improvement
>          Components: Index
>            Reporter: Shai Erera
>            Assignee: Shai Erera
>            Priority: Trivial
>             Fix For: 3.1, 4.0
>         Attachments: LUCENE-2455_3x.patch, LUCENE-2455_3x.patch
> Today, the use of addIndexes and addIndexesNoOptimize is confusing - 
> especially on when to invoke each. Also, addIndexes calls optimize() in 
> the beginning, but only on the target index. It also includes the 
> following jdoc statement, which from how I understand the code, is 
> wrong: _After this completes, the index is optimized._ -- optimize() is 
> called in the beginning and not in the end. 
> On the other hand, addIndexesNoOptimize does not call optimize(), and 
> relies on the MergeScheduler and MergePolicy to handle the merges. 
> After a short discussion about that on the list (Thanks Mike for the 
> clarifications!) I understand that there are really two core differences 
> between the two: 
> * addIndexes supports IndexReader extensions
> * addIndexesNoOptimize performs better
> This issue proposes the following:
> # Clear up the documentation of each, spelling out the pros/cons of 
>   calling them clearly in the javadocs.
> # Rename addIndexesNoOptimize to addIndexes
> # Remove optimize() call from addIndexes(IndexReader...)
> # Document that clearly in both, w/ a recommendation to call optimize() 
>   before on any of the Directories/Indexes if it's a concern. 
> That way, we maintain all the flexibility in the API - 
> addIndexes(IndexReader...) allows for using IR extensions, 
> addIndexes(Directory...) is considered more efficient, by allowing the 
> merges to happen concurrently (depending on MS) and also factors in the 
> MP. So unless you have an IR extension, addDirectories is really the one 
> you should be using. And you have the freedom to call optimize() before 
> each if you care about it, or don't if you don't care. Either way, 
> incurring the cost of optimize() is entirely in the user's hands. 
> BTW, addIndexes(IndexReader...) does not use neither the MergeScheduler 
> nor MergePolicy, but rather call SegmentMerger directly. This might be 
> another place for improvement. I'll look into it, and if it's not too 
> complicated, I may cover it by this issue as well. If you have any hints 
> that can give me a good head start on that, please don't be shy :). 

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