diff --git a/database.sql b/database.sql
index 93f9bbef7e..f0d5854623 100644
--- a/database.sql
+++ b/database.sql
@@ -1071,8 +1071,8 @@ CREATE TABLE IF NOT EXISTS `post-category` (
 	`type` tinyint unsigned NOT NULL DEFAULT 0 COMMENT '',
 	`tid` int unsigned NOT NULL DEFAULT 0 COMMENT '',
 	 PRIMARY KEY(`uri-id`,`uid`,`type`,`tid`),
-	 INDEX `uri-id` (`tid`),
-	 INDEX `uid` (`uid`),
+	 INDEX `tid` (`tid`),
+	 INDEX `uid_uri-id` (`uid`,`uri-id`),
 	FOREIGN KEY (`uri-id`) REFERENCES `item-uri` (`id`) ON UPDATE RESTRICT ON DELETE CASCADE,
 	FOREIGN KEY (`uid`) REFERENCES `user` (`uid`) ON UPDATE RESTRICT ON DELETE CASCADE,
 	FOREIGN KEY (`tid`) REFERENCES `tag` (`id`) ON UPDATE RESTRICT ON DELETE RESTRICT
diff --git a/doc/database/db_post-category.md b/doc/database/db_post-category.md
index b825a8f4b1..f28e306f17 100644
--- a/doc/database/db_post-category.md
+++ b/doc/database/db_post-category.md
@@ -16,11 +16,11 @@ Fields
 Indexes
 ------------
 
-| Name    | Fields                 |
-| ------- | ---------------------- |
-| PRIMARY | uri-id, uid, type, tid |
-| uri-id  | tid                    |
-| uid     | uid                    |
+| Name       | Fields                 |
+| ---------- | ---------------------- |
+| PRIMARY    | uri-id, uid, type, tid |
+| tid        | tid                    |
+| uid_uri-id | uid, uri-id            |
 
 Foreign Keys
 ------------
diff --git a/static/dbstructure.config.php b/static/dbstructure.config.php
index 6d28b29141..df0d469fce 100644
--- a/static/dbstructure.config.php
+++ b/static/dbstructure.config.php
@@ -1114,8 +1114,8 @@ return [
 		],
 		"indexes" => [
 			"PRIMARY" => ["uri-id", "uid", "type", "tid"],
-			"uri-id" => ["tid"],
-			"uid" => ["uid"],
+			"tid" => ["tid"],
+			"uid_uri-id" => ["uid", "uri-id"],
 		]
 	],
 	"post-collection" => [