#24203: Optimisation: adding multiple fields to same model should attempt to run
single ALTER TABLE statement
-------------------------------------+-------------------------------------
Reporter: peterlauri | Owner: nobody
Type: | Status: new
Cleanup/optimization |
Component: Migrations | Version: master
Severity: Normal | Resolution:
Keywords: migration | Triage Stage:
| Someday/Maybe
Has patch: 0 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
-------------------------------------+-------------------------------------
Comment (by peterlauri):
Replying to [comment:2 timgraham]:
> Could you give some performance numbers for comparison?
This is not from production, it contains ~500k rows. I will try it out on
PG as well, just need to prep some data.
{{{
mysql> select count(*) from thetable;
+----------+
| count(*) |
+----------+
| 489484 |
+----------+
1 row in set (0.07 sec)
mysql> ALTER TABLE thetable ADD COLUMN field2 varchar(100) NULL;
Query OK, 489484 rows affected (2 min 29.05 sec)
Records: 489484 Duplicates: 0 Warnings: 0
mysql> ALTER TABLE thetable ADD COLUMN field3 varchar(100) NULL;
Query OK, 489484 rows affected (2 min 10.82 sec)
Records: 489484 Duplicates: 0 Warnings: 0
mysql> ALTER TABLE thetable ADD COLUMN field4 varchar(100) NULL, ADD
COLUMN field5 varchar(100) NULL;
Query OK, 489484 rows affected (2 min 24.92 sec)
Records: 489484 Duplicates: 0 Warnings: 0
mysql>
}}}
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Ticket URL: <https://code.djangoproject.com/ticket/24203#comment:6>
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