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https://issues.apache.org/jira/browse/PHOENIX-5451?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
chenglei updated PHOENIX-5451:
------------------------------
Description:
Phoenix has already could prune column for single flat table query, but for
subselect in subquery or join, column pruning is not implemented.
Consider following join sql :
{code:java}
select a.aid,b.bid from
(select aid,age from table1 where age >=11 and age<=33 order by age limit 3)
a inner join
(select bid,code from table2 order by code limit 1) b on a.aid=b.bid
{code}
for LHS, {{table1.age}} is not referenced by outer join, and for RHS,
{{table2.code}} is also not referenced by outer join, {{table1.age}} and
{{table2.code}} could both be pruned when execute query for LHS and RHS, but
now Phoenix does not prune them.
Another example is subquery sql:
{code:java}
(SELECT t.eid id, t.bstr b FROM
(SELECT entity_id eid, a_string astr, b_string bstr FROM table
WHERE a_byte + 1 < 9 limit 2) t ORDER BY b,id
{code}
for inner subselect sql, {{a_string}} is never used by outer sql, so
{{a_string}} could be pruned when execute query for inner subselect, but now
Phoenix does not prune it.
was:
Phoenix is already doing column prune for single flat table query, but for
subselect in subquery or join, column pruning is not implemented.
Consider following join sql :
{code:java}
select a.aid,b.bid from (select aid,age from table1 where age >=11 and
age<=33 order by age limit 3) a inner join
(select bid,code from table2 order by code limit 1) b on a.aid=b.bid
{code}
for LHS, table1.age is not referenced by outer join, and for RHS, table2.code
is also not referenced by outer join, table1.age and table2.code could both be
pruned when execute query for LHS and RHS, but now Phoenix does not prune them.
Another example is subsquery sql:
{code:java}
{code}
> Column pruning for Subselect
> ----------------------------
>
> Key: PHOENIX-5451
> URL: https://issues.apache.org/jira/browse/PHOENIX-5451
> Project: Phoenix
> Issue Type: Improvement
> Affects Versions: 4.14.2
> Reporter: chenglei
> Priority: Major
> Fix For: 4.15.0, 5.1.0
>
>
> Phoenix has already could prune column for single flat table query, but for
> subselect in subquery or join, column pruning is not implemented.
> Consider following join sql :
> {code:java}
> select a.aid,b.bid from
> (select aid,age from table1 where age >=11 and age<=33 order by age limit
> 3) a inner join
> (select bid,code from table2 order by code limit 1) b on a.aid=b.bid
> {code}
> for LHS, {{table1.age}} is not referenced by outer join, and for RHS,
> {{table2.code}} is also not referenced by outer join, {{table1.age}} and
> {{table2.code}} could both be pruned when execute query for LHS and RHS, but
> now Phoenix does not prune them.
> Another example is subquery sql:
> {code:java}
> (SELECT t.eid id, t.bstr b FROM
> (SELECT entity_id eid, a_string astr, b_string bstr FROM table
> WHERE a_byte + 1 < 9 limit 2) t ORDER BY b,id
> {code}
> for inner subselect sql, {{a_string}} is never used by outer sql, so
> {{a_string}} could be pruned when execute query for inner subselect, but now
> Phoenix does not prune it.
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