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https://issues.apache.org/jira/browse/PHOENIX-3451?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15665899#comment-15665899
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James Taylor commented on PHOENIX-3451:
---------------------------------------
Sorry about that - I based my feedback on your description in your very helpful
analysis. Your patch is indeed on the right track, but it makes some
assumptions. For example, it would only work if a GROUP BY is done directly on
a RowKeyColumnExpression (i.e. GROUP BY pkCol1, pkCol2), but not for cases like
GROUP BY pkCol1 + 1, TRUNC(pkCol2).
I'd recommend adding information to the GroupBy object to capture the pk
position of each Info. You only need to do that here in GroupByCompiler (by
adding a new setter tot he GroupByBuilder):
{code}
if (isOrderPreserving || isUngroupedAggregate) {
return new
GroupBy.GroupByBuilder(this).setIsOrderPreserving(isOrderPreserving).setOrderPreservingColumnCount(orderPreservingColumnCount).build();
}
{code}
At that point, you still have the tracker, so you can add a method like
tracker.getPkPositions() which returns a list or array of int which would be
the position of the primary key that gets passed into the new Builder setter
method. Then you can use that information in the OrderByCompiler if an
aggregation is being done.
> Secondary index and query using distinct: LIMIT doesn't return the first rows
> -----------------------------------------------------------------------------
>
> Key: PHOENIX-3451
> URL: https://issues.apache.org/jira/browse/PHOENIX-3451
> Project: Phoenix
> Issue Type: Bug
> Affects Versions: 4.8.0
> Reporter: Joel Palmert
> Assignee: chenglei
> Attachments: PHOENIX-3451.diff
>
>
> This may be related to PHOENIX-3452 but the behavior is different so filing
> it separately.
> Steps to repro:
> CREATE TABLE IF NOT EXISTS TEST.TEST (
> ORGANIZATION_ID CHAR(15) NOT NULL,
> CONTAINER_ID CHAR(15) NOT NULL,
> ENTITY_ID CHAR(15) NOT NULL,
> SCORE DOUBLE,
> CONSTRAINT TEST_PK PRIMARY KEY (
> ORGANIZATION_ID,
> CONTAINER_ID,
> ENTITY_ID
> )
> ) VERSIONS=1, MULTI_TENANT=TRUE, REPLICATION_SCOPE=1, TTL=31536000;
> CREATE INDEX IF NOT EXISTS TEST_SCORE ON TEST.TEST (CONTAINER_ID, SCORE DESC,
> ENTITY_ID DESC);
> UPSERT INTO test.test VALUES ('org2','container2','entityId6',1.1);
> UPSERT INTO test.test VALUES ('org2','container1','entityId5',1.2);
> UPSERT INTO test.test VALUES ('org2','container2','entityId4',1.3);
> UPSERT INTO test.test VALUES ('org2','container1','entityId3',1.4);
> UPSERT INTO test.test VALUES ('org2','container3','entityId7',1.35);
> UPSERT INTO test.test VALUES ('org2','container3','entityId8',1.45);
> EXPLAIN
> SELECT DISTINCT entity_id, score
> FROM test.test
> WHERE organization_id = 'org2'
> AND container_id IN ( 'container1','container2','container3' )
> ORDER BY score DESC
> LIMIT 2
> OUTPUT
> entityId5 1.2
> entityId3 1.4
> The expected out out would be
> entityId8 1.45
> entityId3 1.4
> You will get the expected output if you remove the secondary index from the
> table or remove distinct from the query.
> As described in PHOENIX-3452 if you run the query without the LIMIT the
> ordering is not correct. However, the 2first results in that ordering is
> still not the onces returned by the limit clause, which makes me think there
> are multiple issues here and why I filed both separately. The rows being
> returned are the ones assigned to container1. It looks like Phoenix is first
> getting the rows from the first container and when it finds that to be enough
> it stops the scan. What it should be doing is getting 2 results for each
> container and then merge then and then limit again.
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