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https://issues.apache.org/jira/browse/PHOENIX-1997?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14553787#comment-14553787
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James Taylor commented on PHOENIX-1997:
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Thanks for the idea, [~zeodtr]. What do you think, [~maryannxue]?
> Join optimization: Apply one table's where condition to the others
> ------------------------------------------------------------------
>
> Key: PHOENIX-1997
> URL: https://issues.apache.org/jira/browse/PHOENIX-1997
> Project: Phoenix
> Issue Type: Improvement
> Affects Versions: 4.3.1
> Reporter: Taeyun Kim
> Priority: Minor
>
> Joined tables are as follows:
> {noformat}
> create table table_a
> (
> time_id integer not null,
> depth tinyint not null,
> id0 integer not null,
> id1 integer not null,
> id2 integer not null,
> id3 integer not null,
> id integer not null,
> record_type smallint not null,
> c varbinary
> constraint pk primary key(time_id, depth, id0, id1, id2, id3, id,
> record_type)
> )
> salt_buckets=4,
> compression='SNAPPY',
> create table table_b
> (
> depth tinyint not null,
> id0 integer not null,
> id1 integer not null,
> id integer not null,
> c varbinary,
> p varbinary
> constraint pk primary key(depth, id0, id1, id)
> )
> salt_buckets=2,
> compression='SNAPPY';
> create index table_b_index on table_b (id, depth, id0, id1)
> compression='SNAPPY';
> {noformat}
> The query is as follows:
> {noformat}
> select a.*, b.c
> from table_a a inner join table_b b on (a.depth = b.depth and a.id0 = b.id0
> and a.id1 = b.id1 and a.id2 = b.id)
> where a.time_id = 23796900 and a.depth = 1;
> {noformat}
> It is obvious that b.depth must also be 1 since it's on the join condition.
> And since the depth column is the first primary key column of table_b,
> table_b should be range scanned before join.
> But the query explanation is as follows:
> {noformat}
> CLIENT PARALLEL 4-WAY RANGE SCAN OVER TABLE_A [0,23796900,1]
> CLIENT MERGE SORT
> PARALLEL INNER-JOIN TABLE 0
> CLIENT PARALLEL 2-WAY FULL SCAN OVER TABLE_B
> CLIENT MERGE SORT
> {noformat}
> But when (b.depth = 1) condition is explicitly added to the query, the
> explanation is changed as the expected one:
> {noformat}
> CLIENT PARALLEL 4-WAY RANGE SCAN OVER TABLE_A [0,23796900,1]
> CLIENT MERGE SORT
> PARALLEL INNER-JOIN TABLE 0
> CLIENT PARALLEL 2-WAY RANGE SCAN OVER TABLE_B [0,1]
> CLIENT MERGE SORT
> {noformat}
> It would be nice if the optimizer could find this condition dependency and
> apply it to the query plan.
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