perf: Translation Memory and Tolgee AI Translator suggestion performa…

…nce (#2459)

backend/data/src/main/kotlin/io/tolgee/service/translation/TranslationMemoryService.kt

@@ -83,9 +83,15 @@ class TranslationMemoryService(
  target.text <> '' and
  target.text is not null
  join key targetKey on target.key_id = targetKey.id 
- where baseTranslation.language_id = p.base_language_id and
- (cast(:key as bigint) is null or targetKey.id <> :key) and targetKey.is_plural = :isPlural
- and baseTranslation.text % :baseTranslationText
+ """ +
+
+ // we use the case when syntax to force postgres to evaluate all the other conditions first,
+ // the similarity condition is slow even it uses index, and it tends to be evaluated first since
+ // huge underestimation
+ """
+ where case when (baseTranslation.language_id = p.base_language_id and
+ (cast(:key as bigint) is null or targetKey.id <> :key) and targetKey.is_plural = :isPlural)
+ then baseTranslation.text % :baseTranslationText end
  ) select base.*, count(*) over() 
  from base
  order by base.similarity desc