Improve query to check if broker has service instances #2855
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Instead of doing (more than) m times n queries (number of services *
number of service plans) a single query joining the required tables is
sufficient.
before
------
1* SELECT * FROM `services` WHERE (`service_broker_id` = ...)
m* SELECT * FROM `service_plans` WHERE (`service_id` = ...)
m*n* SELECT * FROM `service_instances` WHERE (`service_plan_id` = ...)
after
-----
SELECT 1 AS `one`
FROM `service_instances`
INNER JOIN `service_plans`
ON (`service_plans`.`id` = `service_instances`.`service_plan_id`)
INNER JOIN `services`
ON (`services`.`id` = `service_plans`.`service_id`)
WHERE (`services`.`service_broker_id` = 1)
LIMIT 1
philippthun
added a commit
to sap-contributions/cloud_controller_ng
that referenced
this pull request
Jul 11, 2022
There are already several PRs (see below [1]) that change dataset.any? to !dataset.empty? or otherwise mention the difference between these two statements. Whereas the first one fetches all data from the database to then check if the resulting array contains at least one element, the second statement does a 'select 1 as one from table limit 1' query that has a far better performance. Fortunately there is a Sequel extension (see [2]) that 'fixes' this misleading behavior; so instead of searching for more places where we could change the implementation, using dataset.any? should now be equivalent to !dataset.empty? and everyone can choose freely which one to use. [1] cloudfoundry#2117 cloudfoundry#2533 cloudfoundry#2803 cloudfoundry#2855 [2] https://sequel.jeremyevans.net/rdoc-plugins/files/lib/sequel/extensions/any_not_empty_rb.html
5 tasks
will-gant
pushed a commit
to sap-contributions/cloud_controller_ng
that referenced
this pull request
Dec 16, 2022
There are already several PRs (see below [1]) that change dataset.any? to !dataset.empty? or otherwise mention the difference between these two statements. Whereas the first one fetches all data from the database to then check if the resulting array contains at least one element, the second statement does a 'select 1 as one from table limit 1' query that has a far better performance. Fortunately there is a Sequel extension (see [2]) that 'fixes' this misleading behavior; so instead of searching for more places where we could change the implementation, using dataset.any? should now be equivalent to !dataset.empty? and everyone can choose freely which one to use. [1] cloudfoundry#2117 cloudfoundry#2533 cloudfoundry#2803 cloudfoundry#2855 [2] https://sequel.jeremyevans.net/rdoc-plugins/files/lib/sequel/extensions/any_not_empty_rb.html
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Instead of doing (more than) m times n queries (number of services * number of service plans) a single query joining the required tables is sufficient.
before
after
I have reviewed the contributing guide
I have viewed, signed, and submitted the Contributor License Agreement
I have made this pull request to the
mainbranchI have run all the unit tests using
bundle exec rakeI have run CF Acceptance Tests