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https://issues.apache.org/jira/browse/PHOENIX-4757?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16693646#comment-16693646
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Thomas D'Silva commented on PHOENIX-4757:
-----------------------------------------
[~sangudi]
For the table with PK (id_1, id_2, other_key) when you write data are id_1 and
id_2 constant with other_key strictly increasing? I assume this is why you need
salting.
If the salt byte is based only on id_2 wouldn't this lead to write hotspotting?
> composite key salt_buckets
> --------------------------
>
> Key: PHOENIX-4757
> URL: https://issues.apache.org/jira/browse/PHOENIX-4757
> Project: Phoenix
> Issue Type: Improvement
> Affects Versions: 4.11.0
> Reporter: cmd
> Priority: Major
> Fix For: 4.11.0
>
>
> CREATE TABLE IF NOT EXISTS user_events (
> user_id VARCHAR NOT NULL,
> event_type VARCHAR NOT NULL,
> event_time VARCHAR NOT NULL
> event_msg VARCHAR NOT NULL
> event_status VARCHAR NOT NULL
> event_opt VARCHAR NOT NULL
> CONSTRAINT my_pk PRIMARY KEY (user_id,event_type,event_time))
> SALT_BUCKETS=128;
> and my query is:
> 1.select event_type,count(0) from us_population where user_id='xxxx' group
> by event_type
> 2.select count(0) from us_population where user_id='xxxx' and
> event_type='0101'
> 3.select * from us_population where user_id='xxxx' and event_type='0101' and
> event_time>'20180101' and event_time<'20180201' order by event_time limit
> 50,100
> Concurrency query ratio:
> 1:80%
> 2:10%
> 3:10%
> user_events data :50billion
> It can be a field/some fileds of the primary key salted by hash
> grammar with "SALT_BUCKETS(user_id)=4" or
> "SALT_BUCKETS(user_id,event_type)=4"
> ref:
>
> [https://www.safaribooksonline.com/library/view/greenplum-architecture/9781940540337/xhtml/chapter03.xhtml]
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