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https://issues.apache.org/jira/browse/LUCENE-10033?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17402063#comment-17402063
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weizijun commented on LUCENE-10033:
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Hi, [~jpountz], I add a PR in [#1|https://github.com/jpountz/lucene/pull/1].
It talk about compress dv blocks.
In the time series case, it has a good compression ratio. and the speed is
almost the same as not encode.
Can you review this PR?
> Encode doc values in smaller blocks of values, like postings
> ------------------------------------------------------------
>
> Key: LUCENE-10033
> URL: https://issues.apache.org/jira/browse/LUCENE-10033
> Project: Lucene - Core
> Issue Type: Improvement
> Reporter: Adrien Grand
> Priority: Minor
> Time Spent: 1h
> Remaining Estimate: 0h
>
> This is a follow-up to the discussion on this thread:
> https://lists.apache.org/thread.html/r7b757074d5f02874ce3a295b0007dff486bc10d08fb0b5e5a4ba72c5%40%3Cdev.lucene.apache.org%3E.
> Our current approach for doc values uses large blocks of 16k values where
> values can be decompressed independently, using DirectWriter/DirectReader.
> This is a bit inefficient in some cases, e.g. a single outlier can grow the
> number of bits per value for the entire block, we can't easily use run-length
> compression, etc. Plus, it encourages using a different sub-class for every
> compression technique, which puts pressure on the JVM.
> We'd like to move to an approach that would be more similar to postings with
> smaller blocks (e.g. 128 values) whose values get all decompressed at once
> (using SIMD instructions), with skip data within blocks in order to
> efficiently skip to arbitrary doc IDs (or maybe still use jump tables as
> today's doc values, and as discussed here for postings:
> https://lists.apache.org/thread.html/r7c3cb7ab143fd4ecbc05c04064d10ef9fb50c5b4d6479b0f35732677%40%3Cdev.lucene.apache.org%3E).
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