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Posted to dev@phoenix.apache.org by "Istvan Toth (Jira)" <ji...@apache.org> on 2023/06/16 08:21:00 UTC
[jira] [Resolved] (PHOENIX-6980) Push TopN down into joins where applicable
[ https://issues.apache.org/jira/browse/PHOENIX-6980?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Istvan Toth resolved PHOENIX-6980.
----------------------------------
Resolution: Invalid
The Index issue is real, but it's not a general optimization issue.
> Push TopN down into joins where applicable
> ------------------------------------------
>
> Key: PHOENIX-6980
> URL: https://issues.apache.org/jira/browse/PHOENIX-6980
> Project: Phoenix
> Issue Type: Improvement
> Reporter: Istvan Toth
> Assignee: Istvan Toth
> Priority: Major
>
> This came up with an non-merging hinted uncovered index query, which may not be directly applicable in the latest versions{-}, but the same problem is reproducible with a simple IN subquery, which uses the same{-} plan:
> On second thought, this only applies to indexed queries, otherwise there is no guarantee that there is a 1:1 match between the two table rows.
> {noformat}
> CREATE TABLE A(A_ID INTEGER NOT NULL PRIMARY KEY, A_V1 INTEGER);
> CREATE TABLE B(B_ID INTEGER NOT NULL PRIMARY KEY, B_V1 INTEGER);
> explain select * from A where (A_ID, A_V1) in (select B_ID, B_V1 from b ) order by a_v1 limit 10;
> +-----------------------------------------------------------------+----------------+---------------+-------------+
> | PLAN | EST_BYTES_READ | EST_ROWS_READ | EST_INFO_TS |
> +-----------------------------------------------------------------+----------------+---------------+-------------+
> | CLIENT 1-CHUNK PARALLEL 1-WAY FULL SCAN OVER A | null | null | null |
> | SERVER TOP 10 ROWS SORTED BY [A.A_V1] | null | null | null |
> | CLIENT MERGE SORT | null | null | null |
> | CLIENT LIMIT 10 | null | null | null |
> | SKIP-SCAN-JOIN TABLE 0 | null | null | null |
> | CLIENT 1-CHUNK PARALLEL 1-WAY FULL SCAN OVER B | null | null | null |
> | SERVER AGGREGATE INTO DISTINCT ROWS BY [B_ID, B_V1] | null | null | null |
> | CLIENT MERGE SORT | null | null | null |
> | DYNAMIC SERVER FILTER BY A.A_ID IN ($48.$50) | null | null | null |
> +-----------------------------------------------------------------+----------------+---------------+-------------+
> {noformat}
>
>
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