Eagerly load statuses with the main query in Api::V1::FavouritesController #14673
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…oller The old implementation had two queries: 1. The query constructed in Api::V1::FavouritesController#results 2. The query constructed in #cached_favourites, which is merged with 1. Both of them are issued againt PostgreSQL. The combination of the two queries caused the following problems: - The small window between the two queries involves race conditions. - Minor performance inefficiency. Moreover, the construction of query 2, which involves merging with query 1 has a bug. Query 1 is finalized with paginate_by_id, but paginate_by_id returns an array when min_id parameter is specified. The behavior prevents from merging the query, and in the real world, ActiveRecord simply ignores the merge (!), which results in querying the entire scan of statuses and favourites table. This change fixes these issues by simply letting query 1 get all the works done.
Gargron
approved these changes
Aug 28, 2020
For the record, the behavior is found by @abcang. |
thenameisnigel-old
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Sep 6, 2020
…oller (mastodon#14673) The old implementation had two queries: 1. The query constructed in Api::V1::FavouritesController#results 2. The query constructed in #cached_favourites, which is merged with 1. Both of them are issued againt PostgreSQL. The combination of the two queries caused the following problems: - The small window between the two queries involves race conditions. - Minor performance inefficiency. Moreover, the construction of query 2, which involves merging with query 1 has a bug. Query 1 is finalized with paginate_by_id, but paginate_by_id returns an array when min_id parameter is specified. The behavior prevents from merging the query, and in the real world, ActiveRecord simply ignores the merge (!), which results in querying the entire scan of statuses and favourites table. This change fixes these issues by simply letting query 1 get all the works done.
thenameisnigel-old
pushed a commit
to ChatterlyOSE/Chatterly
that referenced
this pull request
Sep 7, 2020
…oller (mastodon#14673) The old implementation had two queries: 1. The query constructed in Api::V1::FavouritesController#results 2. The query constructed in #cached_favourites, which is merged with 1. Both of them are issued againt PostgreSQL. The combination of the two queries caused the following problems: - The small window between the two queries involves race conditions. - Minor performance inefficiency. Moreover, the construction of query 2, which involves merging with query 1 has a bug. Query 1 is finalized with paginate_by_id, but paginate_by_id returns an array when min_id parameter is specified. The behavior prevents from merging the query, and in the real world, ActiveRecord simply ignores the merge (!), which results in querying the entire scan of statuses and favourites table. This change fixes these issues by simply letting query 1 get all the works done.
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The old implementation had two queries:
Api::V1::FavouritesController#results.#cached_favourites, which is merged with 1.Both of them are issued againt PostgreSQL. The combination of the two queries caused the following problems:
Moreover, the construction of query 2, which involves merging with query 1 has a bug. Query 1 is finalized with paginate_by_id, but
paginate_by_idreturns an array whenmin_idparameter is specified. The behavior prevents from merging the query, and in the real world, ActiveRecord simply ignores the merge (!), which results in querying the entire scan ofstatusesandfavouritestable.This change fixes these issues by simply letting query 1 get all the works done.