Lessons about DB (page 4)

The links, tools and tips our engineers and designers share with each other, one “today I learned” at a time.

lessons shared: 68
people sharing: 8
database started in: 2017

dba.stackexchange.com
Is a Postgres long-running query aborted if the connection is lost/broken?
Flávio JuvenalJanuary 21, 2019
stackoverflow.com
Select first row in each GROUP BY group?
Flávio JuvenalJanuary 21, 2019
postgresql.org
PostgreSQL CLUSTER command can speed up large tables that are frequently filtered by a indexed column:
CLUSTER CLUSTER — cluster a table according to an index Synopsis CLUSTER [VERBOSE] table_name [ USING index_name ] CLUSTER [VERBOSE] …
Flávio JuvenalJanuary 4, 2019
github.com
django-partial-index allows you to set partial/conditional indexes and partial unique constraints, which are useful for ensuring data integrity according to your business logic:
Flávio JuvenalNovember 5, 2018
revsys.com
Django Pro-Tip – Slugs as primary keys:
A very common pattern in a Django Project is to have some kind of 'model-type' relationship, where you have some kind of object that can only belong to one of the types defined in the database.
Flávio JuvenalAugust 21, 2018
blog.acolyer.org
Excellent article about how ORMs cause leaky abstractions that lead to performance issues and how fixing them is generally simple:
Flávio JuvenalJune 30, 2018
docs.djangoproject.com
Besides causing unexpected performance problems, a model default ordering in Django can cause problems to values(). Avoid default ordering! #interaction-with-default-ordering-or-order-by
Flávio JuvenalJune 8, 2018
vladmihalcea.com
A beginner’s guide to database locking and the lost update phenomena (examples in Hibernate, but relevant to Django!):
Learn what the lost update problem is and how to overcome this phenomenon using either database isolation levels, lpessimistic or optimistic ocking.
Flávio JuvenalMay 23, 2018
cybertec-postgresql.com
Are triggers really that slow in Postgres?
Flávio JuvenalMay 23, 2018
legitimatesounding.com
Stupid PostgreSQL Tricks: Writable Views (not really recommended, but interesting!):
Flávio JuvenalMay 23, 2018
stackoverflow.com
Django transaction.atomic is not a lock!
Flávio JuvenalMay 18, 2018
stackoverflow.com
On Django, you should NOT use loaddata management command directly in a data migration. It will use the current model state...
On Django, you should NOT use loaddata management command directly in a data migration. It will use the current model state, not the historical one, therefore your migration will certainly BREAK in the future:
Flávio JuvenalMay 7, 2018
dba.stackexchange.com
On PostgreSQL, use substring function with regex along with multiple columns on order by to properly mix numeric with alphabetical order:
Flávio JuvenalApril 25, 2018
stackoverflow.com
ORDER BY the IN value list:
Flávio JuvenalApril 3, 2018
medium.com
9 Django Tips for Working with Databases:
Flávio JuvenalFebruary 15, 2018

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Lessons about DB (page 4)

Is a Postgres long-running query aborted if the connection is lost/broken?

Is a Postgres long-running query aborted if the connection is lost/broken?

Select first row in each GROUP BY group?

Select first row in each GROUP BY group?

PostgreSQL CLUSTER command can speed up large tables that are frequently filtered by a indexed column:

PostgreSQL CLUSTER command can speed up large tables that are frequently filtered by a indexed column:

django-partial-index allows you to set partial/conditional indexes and partial unique constraints, which are useful for ensuring data integrity according to your business logic:

django-partial-index allows you to set partial/conditional indexes and partial unique constraints, which are useful for ensuring data integrity according to your business logic:

Django Pro-Tip – Slugs as primary keys:

Django Pro-Tip – Slugs as primary keys:

Excellent article about how ORMs cause leaky abstractions that lead to performance issues and how fixing them is generally simple:

Excellent article about how ORMs cause leaky abstractions that lead to performance issues and how fixing them is generally simple:

Besides causing unexpected performance problems, a model default ordering in Django can cause problems to `values()`. Avoid default ordering! #interaction-with-default-ordering-or-order-by

Besides causing unexpected performance problems, a model default ordering in Django can cause problems to `values()`. Avoid default ordering! #interaction-with-default-ordering-or-order-by

A beginner’s guide to database locking and the lost update phenomena (examples in Hibernate, but relevant to Django!):

A beginner’s guide to database locking and the lost update phenomena (examples in Hibernate, but relevant to Django!):

Are triggers really that slow in Postgres?

Are triggers really that slow in Postgres?

Stupid PostgreSQL Tricks: Writable Views (not really recommended, but interesting!):

Stupid PostgreSQL Tricks: Writable Views (not really recommended, but interesting!):

Django transaction.atomic is not a lock!

Django transaction.atomic is not a lock!

On Django, you should NOT use `loaddata` management command directly in a data migration. It will use the current model state...

On Django, you should NOT use `loaddata` management command directly in a data migration. It will use the current model state...

On PostgreSQL, use `substring` function with regex along with multiple columns on `order by` to properly mix numeric with alphabetical order:

On PostgreSQL, use `substring` function with regex along with multiple columns on `order by` to properly mix numeric with alphabetical order:

ORDER BY the IN value list:

ORDER BY the IN value list:

9 Django Tips for Working with Databases:

9 Django Tips for Working with Databases:

Found it useful?
Let’s put it to work.

Lessons about DB (page 4)

Is a Postgres long-running query aborted if the connection is lost/broken?

Select first row in each GROUP BY group?

PostgreSQL CLUSTER command can speed up large tables that are frequently filtered by a indexed column:

django-partial-index allows you to set partial/conditional indexes and partial unique constraints, which are useful for ensuring data integrity according to your business logic:

Django Pro-Tip – Slugs as primary keys:

Excellent article about how ORMs cause leaky abstractions that lead to performance issues and how fixing them is generally simple:

Besides causing unexpected performance problems, a model default ordering in Django can cause problems to values(). Avoid default ordering! #interaction-with-default-ordering-or-order-by

A beginner’s guide to database locking and the lost update phenomena (examples in Hibernate, but relevant to Django!):

Are triggers really that slow in Postgres?

Stupid PostgreSQL Tricks: Writable Views (not really recommended, but interesting!):

Django transaction.atomic is not a lock!

On Django, you should NOT use loaddata management command directly in a data migration. It will use the current model state...

On PostgreSQL, use substring function with regex along with multiple columns on order by to properly mix numeric with alphabetical order:

ORDER BY the IN value list:

9 Django Tips for Working with Databases:

Found it useful? Let’s put it to work.

Besides causing unexpected performance problems, a model default ordering in Django can cause problems to `values()`. Avoid default ordering! #interaction-with-default-ordering-or-order-by

On Django, you should NOT use `loaddata` management command directly in a data migration. It will use the current model state...

On PostgreSQL, use `substring` function with regex along with multiple columns on `order by` to properly mix numeric with alphabetical order:

Found it useful?
Let’s put it to work.