adw0rd.
← All posts
·2 min read

Released a pluggable application "django-sql-stacktrace"

Читать по-русски
DjangoMySQLPythonРелизы

This application is puts python stack trace to a SQL-query as comment. It’s useful when you is debugging your project, when you see many SQL-queries and do not understand where these queries were launched.

PyPI: django-sql-stacktrace

For example, you have come to a new project and you have been asked to deal with a lot of SQL-queries that hang at run time. You look at the “processlist” and see a lot of different SQL-queries:


...

SELECT COUNT(*) FROM `films_film` INNER JOIN `films_year` ON (`films_film`.`year_id` = 
`films_year`.`id`) WHERE (`films_film`.`status` = 'published' AND `films_year`.`id` IS NOT NULL);

SELECT `blogs_post`.`id`, `blogs_post`.`blog_id`, `blogs_post`.`title`, `blogs_post`.`slug`, 
`blogs_post`.`status`, `blogs_post`.`created`, `blogs_post`.`updated`, 
`blogs_post`.`published`, `blogs_post`.`description`, `blogs_post`.`thumbnail`, 
`blogs_post`.`content`, `blogs_post`.`count_of_views`, `blogs_post`.`source_content`, 
`blogs_post`.`source_published`, `blogs_post`.`source_count_views`, 
`blogs_post`.`source_author_of_content`, `blogs_post`.`source_author_of_photo`, 
`blogs_post`.`source_keywords`, `blogs_post`.`source_url` FROM `blogs_post` WHERE 
`blogs_post`.`status` = 'published' ORDER BY `blogs_post`.`published` DESC LIMIT 4;

SELECT `social_auth_usersocialauth`.`id`, `social_auth_usersocialauth`.`user_id`, 
`social_auth_usersocialauth`.`provider`, `social_auth_usersocialauth`.`uid`, 
`social_auth_usersocialauth`.`extra_data` FROM `social_auth_usersocialauth` WHERE 
`social_auth_usersocialauth`.`user_id` = 42;

SELECT `films_film`.`id`, `films_film`.`status`, `films_film`.`created`, `films_film`.`updated`, 
`films_film`.`published`, `films_film`.`title_original`, `films_film`.`title_ru`, `films_film`.`slug`, 
`films_film`.`thumbnail`, `films_film`.`slogan`, `films_film`.`description`, 
`films_film`.`date_premiere`, `films_film`.`year_id`, `films_film`.`rating_votes`, 
`films_film`.`rating_score`, `films_film`.`rating_score_with_vote_weight`, `films_year`.`id`, 
`films_year`.`name`, `films_year`.`count`, `films_year`.`size` FROM `films_film` LEFT OUTER 
JOIN `films_year` ON (`films_film`.`year_id` = `films_year`.`id`) WHERE (`films_film`.`status` 
= 'published'  AND `films_year`.`id` IS NOT NULL) ORDER BY `films_film`.`published` DESC 
LIMIT 30;

...

Where did they run you do not know, moreover, it is not only the queries from views, it may also be sql-queries from the django commands, something daemons, etc.

No problem! You take django-sql-stacktrace, run on a local copy of the project and see the following:


...

SELECT COUNT(*) FROM `films_film` INNER JOIN `films_year` ON (`films_film`.`year_id` = `films_year`.`id`)
WHERE (`films_film`.`status` = 'published' AND `films_year`.`id` IS NOT NULL)
/* STACKTRACE: 
> File "/home/adw0rd/work/kinsburg_tv/kinsburg_tv/common/views.py", line 27, in get_context_data
> context = super(MainPage, self).get_context_data(**kwargs)

STACKTRACE: 
> File "/home/adw0rd/work/kinsburg_tv/kinsburg_tv/films/mixins.py", line 14, in get_context_data
> context = super(FilmsMixin, self).get_context_data(**kwargs)

STACKTRACE: 
> File "/home/adw0rd/work/kinsburg_tv/venv/local/lib/python2.7/site-packages/django/db/models/query.py", line 351, in count
> return self.query.get_count(using=self.db)

STACKTRACE: 
> File "/home/adw0rd/work/kinsburg_tv/venv/local/lib/python2.7/site-packages/django/db/models/sql/query.py", line 418, in get_count
> number = obj.get_aggregation(using=using)[None]

STACKTRACE: 
> File "/home/adw0rd/work/kinsburg_tv/venv/local/lib/python2.7/site-packages/django/db/models/sql/query.py", line 384, in get_aggregation
> result = query.get_compiler(using).execute_sql(SINGLE)

STACKTRACE: 
> File "/home/adw0rd/work/kinsburg_tv/venv/local/lib/python2.7/site-packages/django/db/models/sql/compiler.py", line 818, in execute_sql
> cursor.execute(sql, params)

STACKTRACE: 
> File "/home/adw0rd/work/kinsburg_tv/venv/local/lib/python2.7/site-packages/sqlstacktrace/stacktracecursor.py", line 16, in execute
> stacks = get_stacktrace()

STACKTRACE: 
> File "/home/adw0rd/work/kinsburg_tv/venv/local/lib/python2.7/site-packages/sqlstacktrace/stacktrace.py", line 93, in get_stacktrace
> stack = get_stack()
*/;

...

Good job! Now you know where these queries were launched and has something to do with this problem.

Installation and configuration

Install from PyPI:

pip install django-sql-stacktrace

Or install the dev-version from GitHub:

pip install -e git://github.com/adw0rd/django-sql-stacktrace.git#egg=sqlstacktrace

Now, add to “INSTALLED_APPS”:

INSTALLED_APPS = (
    ...
    'sqlstacktrace',
    ...
)

And turn on the SQL_STACKTRACE:

SQL_STACKTRACE = True

Getting code

You can get django-sql-stacktrace from https://github.com/adw0rd/django-sql-stacktrace. The application is distributed by BSD license.

Comments are closed.