| From: | "Jung, Jinho" <jinho(dot)jung(at)gatech(dot)edu> |
|---|---|
| To: | "pgsql-hackers(at)lists(dot)postgresql(dot)org" <pgsql-hackers(at)lists(dot)postgresql(dot)org> |
| Subject: | Regarding query minimizer (simplifier) |
| Date: | 2018-10-13 16:12:03 |
| Message-ID: | DM5PR07MB3927B3C39041AED5C5F6FB96EEE30@DM5PR07MB3927.namprd07.prod.outlook.com |
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| Lists: | pgsql-hackers |
Hello, I am Jinho Jung, Phd Student from GeorgiaTech, and try to find any SQL queries that cause performance regression. While conducting evaluation, I found an interesting query which makes x80 times slower execution in version 10.5 than version 9.4. Please see the attached files, if you are interested.
To analyze the root cause of problem, I had to find minimal query that contains same problem. (i.e., same regression issue) The initial query was about 14K and I should manually remove part of query. (it took about 30 minutes to get 500 bytes query) So I am wondering if there are tools to automatically simplify statements to analyze the performance issue.
Thanks,
Jinho Jung
| Attachment | Content-Type | Size |
|---|---|---|
| query6_manually_minimize | application/octet-stream | 488 bytes |
| query6_original | application/octet-stream | 14.2 KB |
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