[PHOENIX-153] Implement TABLESAMPLE clause - ASF JIRA

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Details

Type: Task
Status: Resolved
Resolution: Fixed
Affects Version/s: None
Fix Version/s: 4.12.0
Component/s: None
Labels:
- enhancement

old issue number:
22

Description

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