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https://issues.apache.org/jira/browse/PHOENIX-2417?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15102205#comment-15102205
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ASF GitHub Bot commented on PHOENIX-2417:
-----------------------------------------
Github user JamesRTaylor commented on the pull request:
https://github.com/apache/phoenix/pull/147#issuecomment-172037773
Thanks for the patch, @ankitsinghal. The main remaining issues are around
not treating an ImmutableBytesWritable the same as a byte[]. Maybe easiest for
now to have BaseResultIterators.getParallelScans() declare currentKey as an
ImmutableBytesWritable, but keep
// Do this as infrequently as possible to prevent a copy of the backing
byte array
byte[] currentKeyBytes = SchemaUtil.copyKeyIfNecessary(currentKey);
byte[] currentGuidePostBytes =
SchemaUtil.copyKeyIfNecessary(currentGuidePost);
Scan newScan = scanRanges.intersectScan(scan, currentKeyBytes,
currentGuidePostBytes, keyOffset, false);
scans = addNewScan(parallelScans, scans, newScan,
currentGuidePostBytes, false, regionLocation);
> Compress memory used by row key byte[] of guideposts
> ----------------------------------------------------
>
> Key: PHOENIX-2417
> URL: https://issues.apache.org/jira/browse/PHOENIX-2417
> Project: Phoenix
> Issue Type: Sub-task
> Reporter: James Taylor
> Assignee: Ankit Singhal
> Fix For: 4.7.0
>
> Attachments: PHOENIX-2417.patch, PHOENIX-2417_encoder.diff,
> PHOENIX-2417_v2_wip.patch
>
>
> We've found that smaller guideposts are better in terms of minimizing any
> increase in latency for point scans. However, this increases the amount of
> memory significantly when caching the guideposts on the client. Guidepost are
> equidistant row keys in the form of raw byte[] which are likely to have a
> large percentage of their leading bytes in common (as they're stored in
> sorted order. We should use a simple compression technique to mitigate this.
> I noticed that Apache Parquet has a run length encoding - perhaps we can use
> that.
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