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https://issues.apache.org/jira/browse/PHOENIX-3390?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15616135#comment-15616135
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Swapna Kasula commented on PHOENIX-3390:
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Hi James,
Thanks for your response. Please find my inline comments.
- we wouldn't want to introduce an aggregate function that requires column
names to be in quotes.
<swapna> column names shouldn't be required to provide in quotes.
it would look like this: select APPROX_SUM(col1) </swapna>
- we'd want to make sure the name of the aggregate functions reflect what they
do. For example, hllUnion(my_col) would not have any meaning to users.
<swapna> Agree with you. we can change the function name from hllUnion to
APPROX_SUM as you suggested.</swapna>
- we'd want to make sure that you can include any expression in the arguments,
for example, approx_sum(col1/col2 * col3)
<swapna> Please clarify the objective of providing the expression as like this
: col1/col2 * col3 for HLL's .
because the set operations that HLL's supports are: union and intersection.
</swapna>
> Custom UDAF for HyperLogLogPlus
> -------------------------------
>
> Key: PHOENIX-3390
> URL: https://issues.apache.org/jira/browse/PHOENIX-3390
> Project: Phoenix
> Issue Type: New Feature
> Reporter: Swapna Kasula
> Priority: Minor
>
> With ref # PHOENIX-2069
> Custome UDAF to aggregate/union of Hyperloglog's of a column and returns a
> Hyperloglog.
> select hllUnion(col1) from table; //returns a Hyperloglog, which is the
> union of all hyperloglog's from all rows for column 'col1'
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