| From: | Alexey Bashtanov <bashtanov(at)imap(dot)cc> |
|---|---|
| To: | pgsql-hackers(at)postgresql(dot)org |
| Subject: | patch: optimize information_schema.constraint_column_usage |
| Date: | 2017-02-02 13:27:51 |
| Message-ID: | 2d533e5b-687a-09fa-a772-dac9e6cf9dd4@imap.cc |
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| Lists: | pgsql-hackers |
Hello hackers,
The view information_schema.constraint_column_usage becomes slow when
the number of columns and constraints raise to substantial values.
This is because of a join condition that allows only join filter to
enforce. The patch is to optimize it.
See many_constraints.sql file attached for a performance test: create
3000 tables with 10 columns and a PK each and select * from the view.
The last statement works for 22 seconds on master branch, 34
milliseconds optimized on my laptop.
Best Regards,
Alexey Bashtanov
| Attachment | Content-Type | Size |
|---|---|---|
| many-constraints.sql | application/sql | 811 bytes |
| constraint_column_usage.1.patch | text/x-patch | 880 bytes |
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