stash/pkg/sqlite/migrations/28_images_indexes.up.sql

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Add indexes for path and checksum to images (#1740) * Add indexes for path and checksum to images The scenes table has unique indexes/constraints on path and checksum colums. The images table doesn't, which doesn't really make sense, as scanning uses these colums extensively which warrents an index, and both should be unique as well. Adding these indexes thus heavily improves the scanning tasks performance. On a database containing 4700 images a (re)scan of those 4700 files, which thus shouldn't do anything, took 1.2 seconds, with the indexes added this only takes 0.4 seconds. Taking the same test on a generated database containing 4M images + the actual 4700 images took 26 minutes for a rescan, and with the index existing also only takes 0.4 seconds. * Add images.checksum unique constraint in code with fallback Work around the issue where in some cases duplicate images (/checksums on images) might exist. This as discussed in #1740 by creating the index on startup and in case of an error logging the duplicates. This so the users where this scenario exists can correct the database (by searching on the logged checksum(s) and removing the duplicates) and after a restart the unique index / constraint will still be created. In case when creating the unique index fails a "normal" / non-unique index is created as surrogate so the user will still get the performance benefit (for example during scanning) without being forced to remove the duplicates and restart beforehand. This surrogate is also automatically cleaned up after the unique index is succesfully created.
2021-09-21 01:48:52 +00:00
DROP INDEX IF EXISTS `images_path_unique`;
CREATE UNIQUE INDEX `images_path_unique` ON `images` (`path`);