From ea1c1d046856ab46e6bda1903c97702292e61ff9 Mon Sep 17 00:00:00 2001 From: Shadowghost Date: Sat, 7 Mar 2026 20:14:04 +0100 Subject: Optimize grouping query performance --- .../Item/BaseItemRepository.QueryBuilding.cs | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) (limited to 'Jellyfin.Server.Implementations/Item/BaseItemRepository.QueryBuilding.cs') diff --git a/Jellyfin.Server.Implementations/Item/BaseItemRepository.QueryBuilding.cs b/Jellyfin.Server.Implementations/Item/BaseItemRepository.QueryBuilding.cs index d4cdfdbc3e..b1f7326d06 100644 --- a/Jellyfin.Server.Implementations/Item/BaseItemRepository.QueryBuilding.cs +++ b/Jellyfin.Server.Implementations/Item/BaseItemRepository.QueryBuilding.cs @@ -68,19 +68,21 @@ public sealed partial class BaseItemRepository // for that case the invoker has to run a DistinctBy(e => e.PresentationUniqueKey) on their own var enableGroupByPresentationUniqueKey = EnableGroupByPresentationUniqueKey(filter); + // Use Min(Id) instead of OrderBy(Id).FirstOrDefault() to avoid EF Core generating + // a correlated scalar subquery per group. if (enableGroupByPresentationUniqueKey && filter.GroupBySeriesPresentationUniqueKey) { - var tempQuery = dbQuery.GroupBy(e => new { e.PresentationUniqueKey, e.SeriesPresentationUniqueKey }).Select(e => e.OrderBy(x => x.Id).FirstOrDefault()).Select(e => e!.Id); + var tempQuery = dbQuery.GroupBy(e => new { e.PresentationUniqueKey, e.SeriesPresentationUniqueKey }).Select(e => e.Min(x => x.Id)); dbQuery = context.BaseItems.Where(e => tempQuery.Contains(e.Id)); } else if (enableGroupByPresentationUniqueKey) { - var tempQuery = dbQuery.GroupBy(e => e.PresentationUniqueKey).Select(e => e.OrderBy(x => x.Id).FirstOrDefault()).Select(e => e!.Id); + var tempQuery = dbQuery.GroupBy(e => e.PresentationUniqueKey).Select(e => e.Min(x => x.Id)); dbQuery = context.BaseItems.Where(e => tempQuery.Contains(e.Id)); } else if (filter.GroupBySeriesPresentationUniqueKey) { - var tempQuery = dbQuery.GroupBy(e => e.SeriesPresentationUniqueKey).Select(e => e.OrderBy(x => x.Id).FirstOrDefault()).Select(e => e!.Id); + var tempQuery = dbQuery.GroupBy(e => e.SeriesPresentationUniqueKey).Select(e => e.Min(x => x.Id)); dbQuery = context.BaseItems.Where(e => tempQuery.Contains(e.Id)); } else -- cgit v1.2.3