From fc6cafa15f42516373e452e75eacacf981e70c2e Mon Sep 17 00:00:00 2001
From: gitgiggety <79809426+gitgiggety@users.noreply.github.com>
Date: Tue, 17 Aug 2021 05:43:22 +0200
Subject: [PATCH] Fix hierarchical criteria performance issue (#1643)

* Fix hierarchical criteria performance issue

Don't apply recursive clause to hierarchical criteria when the depth is
set to 0 (i.e.: no recursion is needed).

This undoes the current performance penalty on for example the studios
page. This as reported in #1519, using a database of 4M images, 30K
scenes and 500 studios. Without this fix loading the studios overview,
with the default of 40 items per page, takes 6 to 7 seconds. With this
fix it only takes 0,07 seconds reverting the performance back to the
pre-hierarchical filtering performance (tested against 508f7b84 which
was the last commit before #1397 was merged).
---
 pkg/sqlite/filter.go                          | 23 +++++++++++++------
 .../src/components/Changelog/versions/v090.md |  1 +
 2 files changed, 17 insertions(+), 7 deletions(-)

diff --git a/pkg/sqlite/filter.go b/pkg/sqlite/filter.go
index cb8e56e97..1517bf99a 100644
--- a/pkg/sqlite/filter.go
+++ b/pkg/sqlite/filter.go
@@ -539,18 +539,27 @@ func addHierarchicalWithClause(f *filterBuilder, value []string, derivedTable, t
 		depthCondition = fmt.Sprintf("WHERE depth < %d", depth)
 	}
 
-	withClause := utils.StrFormat(`RECURSIVE {derivedTable} AS (
-SELECT id as id, id as child_id, 0 as depth FROM {table} 
-WHERE id in {inBinding} 
-UNION SELECT p.id, c.id, depth + 1 FROM {table} as c 
-INNER JOIN {derivedTable} as p ON c.{parentFK} = p.child_id {depthCondition})
-`, utils.StrFormatMap{
+	withClauseMap := utils.StrFormatMap{
 		"derivedTable":   derivedTable,
 		"table":          table,
 		"inBinding":      getInBinding(inCount),
 		"parentFK":       parentFK,
 		"depthCondition": depthCondition,
-	})
+		"unionClause":    "",
+	}
+
+	if depth != 0 {
+		withClauseMap["unionClause"] = utils.StrFormat(`
+UNION SELECT p.id, c.id, depth + 1 FROM {table} as c
+INNER JOIN {derivedTable} as p ON c.{parentFK} = p.child_id {depthCondition}
+`, withClauseMap)
+	}
+
+	withClause := utils.StrFormat(`RECURSIVE {derivedTable} AS (
+SELECT id as id, id as child_id, 0 as depth FROM {table}
+WHERE id in {inBinding}
+{unionClause})
+`, withClauseMap)
 
 	f.addWith(withClause, args...)
 }
diff --git a/ui/v2.5/src/components/Changelog/versions/v090.md b/ui/v2.5/src/components/Changelog/versions/v090.md
index 51c28b421..69c23e827 100644
--- a/ui/v2.5/src/components/Changelog/versions/v090.md
+++ b/ui/v2.5/src/components/Changelog/versions/v090.md
@@ -19,6 +19,7 @@
 * Added de-DE language option. ([#1578](https://github.com/stashapp/stash/pull/1578))
 
 ### 🐛 Bug fixes
+* Fix performance issue on Studios page getting studio image count. ([#1643](https://github.com/stashapp/stash/pull/1643))
 * Regenerate scene phash if overwrite flag is set. ([#1633](https://github.com/stashapp/stash/pull/1633))
 * Create .stash directory in $HOME only if required. ([#1623](https://github.com/stashapp/stash/pull/1623))
 * Include stash id when scraping performer from stash-box. ([#1608](https://github.com/stashapp/stash/pull/1608))