Dren created IGNITE-17900:
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Summary: Very slow SQL execution with LEFT JOIN and subquery after
upgrade from 2.7.6
Key: IGNITE-17900
URL: https://issues.apache.org/jira/browse/IGNITE-17900
Project: Ignite
Issue Type: Bug
Components: sql
Affects Versions: 2.14, 2.13
Environment: One node test instalation, 6 vCPU 8GB RAM.
Ignite 2.14.0
jdk-13.0.2
Reporter: Dren
Attachments: CREATE_TABLE1.sql, explain_plan.txt, ignite_log.txt,
insert_data.sql
After migration form Ignite 2.7.6 to Ignite 2.13 I noticed that the query below
executes very slowly. A big difference in execution time can be seen already in
tables with several thousands of records. If table have more than 100,000
records, the query will never finish.
select T0.* , T1.HIDE
from TABLE1 as T0
left JOIN
( select key1, key2, count(*) AS HIDE
from TABLE1
GROUP BY key1, key2
) as T1
ON T0.key1 = T1.key1 AND T0.key2 = T1.key2;
-- Ignite v2.13.0 and v2.14.0
-- execution time 8 seconds with 2100 records
-- execution time 22 seconds with 4400 records
-- Ignite v 2.7.6
-- execution time 3ms with 2100 records
-- execution time 4ms seconds with 4400 records
All DDL and test data can be found in attachment.
I tried adding indexes to the key1 and key2 columns, but the result is always
the same.
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