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https://issues.apache.org/jira/browse/BLUR-220?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Ravikumar updated BLUR-220:
---------------------------
Attachment: SlabRAMFile.java
SlabRAMInputStream.java
SlabAllocator.java
SlabRAMOutputStream.java
SlabRAMDirectory.java
Ok, somethings that I gathered.
If we are to use a RAM-based directory, then it's definitely not going to be a
RAMDirectory. Even the javadocs has warnings!!!
I quickly grabbed the SlabAllocator from Cassandra [Which is again grabbed from
HBase], that doles out 1 MB byte[] and wrap it up with lucene's BytesRef. Each
RAMFile contains N-chunks of BytesRef with chunk-size=64KB.
I believe it should be both friendly on GC-cycles for few GB's of RAM as well
as quite performant under concurrent loads. Patch attached.
In Blur code, I see everywhere a "waitTobeVisible" flag, instructing NRTManager
to wait till that generation. How should I understand that in the context of a
RAMDirectory, backed by a HDFSDirectory? What should be the correct way to
approach this?
> Support for humongous Rows
> --------------------------
>
> Key: BLUR-220
> URL: https://issues.apache.org/jira/browse/BLUR-220
> Project: Apache Blur
> Issue Type: Improvement
> Components: Blur
> Affects Versions: 0.3.0
> Reporter: Aaron McCurry
> Fix For: 0.3.0
>
> Attachments: Blur_Query_Perf_Chart1.pdf, CreateIndex.java,
> CreateIndex.java, CreateSortedIndex.java, FullRowReindexing.java,
> MyEarlyTerminatingCollector.java, SlabAllocator.java, SlabRAMDirectory.java,
> SlabRAMFile.java, SlabRAMInputStream.java, SlabRAMOutputStream.java,
> test_results.txt, TestSearch.java, TestSearch.java
>
>
> One of the limitations of Blur is size of Rows stored, specifically the
> number of Records. The current updates are performed on Lucene is by
> deleting the document and re-adding to the index. Unfortunately when any
> update is perform on a Row in Blur, the entire Row has to be re-read (if the
> RowMutationType is UPDATE_ROW) and then whatever modification needs are made
> then it is reindexed in it's entirety.
> Due to all of this overhead, there is a realistic limit on the size of a
> given Row. It may vary based the kind of hardware that is being used, as the
> Row grows in size the indexing (mutations) against that Row will slow.
> This issue is being created to discuss techniques on how to deal with this
> problem.
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