[
https://issues.apache.org/jira/browse/LUCENE-845?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#action_12526460
]
Michael McCandless commented on LUCENE-845:
-------------------------------------------
> Shound minMergeDocs default to maxBufferedDocs (that should yield
> the old behavior)?
Good idea -- I think we could do this dynamically so that whenever
IndexWriter is flushing by doc count and the merge policy is
LogDocMergePolicy we "write through" any changes to maxBufferedDocs
--> LogDocMergePolicy.setMinMergeDocs? I'll take that approach to
keep backwards compatibility.
> Although 1000 isn't bad... much better to slow indexing a little in
> the odd app than to break it by running it out of descriptors.
Agreed, that's the right direction to "err" here.
> If you "flush by RAM usage" then IndexWriter may over-merge
> -----------------------------------------------------------
>
> Key: LUCENE-845
> URL: https://issues.apache.org/jira/browse/LUCENE-845
> Project: Lucene - Java
> Issue Type: Bug
> Components: Index
> Affects Versions: 2.1
> Reporter: Michael McCandless
> Assignee: Michael McCandless
> Priority: Minor
> Fix For: 2.3
>
> Attachments: LUCENE-845.patch
>
>
> I think a good way to maximize performance of Lucene's indexing for a
> given amount of RAM is to flush (writer.flush()) the added documents
> whenever the RAM usage (writer.ramSizeInBytes()) has crossed the max
> RAM you can afford.
> But, this can confuse the merge policy and cause over-merging, unless
> you set maxBufferedDocs properly.
> This is because the merge policy looks at the current maxBufferedDocs
> to figure out which segments are level 0 (first flushed) or level 1
> (merged from <mergeFactor> level 0 segments).
> I'm not sure how to fix this. Maybe we can look at net size (bytes)
> of a segment and "infer" level from this? Still we would have to be
> resilient to the application suddenly increasing the RAM allowed.
> The good news is to workaround this bug I think you just need to
> ensure that your maxBufferedDocs is less than mergeFactor *
> typical-number-of-docs-flushed.
--
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.
---------------------------------------------------------------------
To unsubscribe, e-mail: [EMAIL PROTECTED]
For additional commands, e-mail: [EMAIL PROTECTED]
