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https://issues.apache.org/jira/browse/PHOENIX-153?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16622425#comment-16622425
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Karan Mehta commented on PHOENIX-153:
-------------------------------------
[~aertoria]
[TableSamplerPredicate|https://github.com/apache/phoenix/blob/master/phoenix-core/src/main/java/org/apache/phoenix/iterate/TableSamplerPredicate.java]
file describes the hashing algorithm as FNV1a hash, however it uses Java
hashCode method on the byte array of input row. If I understand correctly, the
implementation of hashCode is different than FNV1a hash (which involves
operations like XOR)
Am I missing something here or this is how it was designed?
FYI [~Bin Shi]
> Implement TABLESAMPLE clause
> ----------------------------
>
> Key: PHOENIX-153
> URL: https://issues.apache.org/jira/browse/PHOENIX-153
> Project: Phoenix
> Issue Type: Task
> Reporter: James Taylor
> Assignee: Ethan Wang
> Labels: enhancement
> Fix For: 4.12.0
>
> Attachments: Sampling_Accuracy_Performance.jpg
>
>
> Support the standard SQL TABLESAMPLE clause by implementing a filter that
> uses a skip next hint based on the region boundaries of the table to only
> return n rows per region.
> When TABLESAMPLE clause is used, Phoenix will sample (N) percent of the the
> hbase table with only O(M) run time complexity. (N is size of table, M is
> size of stats)
> [Update]
> Usage:
> https://phoenix.apache.org/tablesample.html
> Syntax of using table sampling:
> select * from PERSON TABLESAMPLE(45);
> select count( * ) from PERSON TABLESAMPLE (49) LIMIT 2
> Source Code:
> https://git-wip-us.apache.org/repos/asf?p=phoenix.git;a=commitdiff;h=5e33dc12bc088bd0008d89f0a5cd7d5c368efa25
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