All Questions
6 questions
2
votes
1
answer
1k
views
Why do my RDS read IOPS drop after a certain period of time?
I am trying to add non-null constraints on several columns in a table with about 70,000,000 rows. Each statement is just ALTER TABLE table_name ALTER COLUMN column_name SET NOT NULL;, and each ...
- 179
3
votes
1
answer
473
views
Does "alter table … set data type" functionally differ from "alter table … type"?
The docs show [SET DATA] TYPE which implies the SET DATA part is optional, but the 9.1 release notes also imply that SET DATA TYPE may be different:
Allow ALTER TABLE ... SET DATA TYPE to avoid ...
- 133
0
votes
0
answers
771
views
Possibility of using self-referential foreign key to create hierarchical comments
I am an accidental DBA and have a question regarding the table structure of a website I maintain (postgresql 9.6 backend).
Imagine a typical content website (let's call it 'Links'), where users post ...
- 2,039
4
votes
0
answers
1k
views
How costly is changing column datatype in PostgreSQL?
I'm currently evaluating PostgreSQL for an app we are developing which comes with a weird usecase. We want to allow clients to create new fields which in turn will create new columns in a client-...
- 141
1
vote
1
answer
532
views
Query Performance When Dropping Multiple Columns
In PostgreSQL, is there any performance gain when using a single ALTER TABLE statement to drop multiple columns, instead of using a separate statement to drop each column?
ALTER TABLE table DROP ...
- 113
8
votes
2
answers
24k
views
Add column with default in postgresql without table level lock
Have such a problem - table with over 20mln rows.
When i add new column with default - postgresql lock table for over 40 minutes so my application stop working for this time.
So instead of
ALTER ...
- 183