From 4c8e6ef4958aac495bcafaa6a0afe63a53c61933 Mon Sep 17 00:00:00 2001
From: "B. Petersen" <r10s@b44t.com>
Date: Sat, 10 Oct 2020 00:32:45 +0200
Subject: [PATCH] use combined index (state, hidden, chat_id) to speed up
 marknoticed_chat()

---
 src/chat.rs | 14 ++++++++------
 src/sql.rs  |  2 +-
 2 files changed, 9 insertions(+), 7 deletions(-)

diff --git a/src/chat.rs b/src/chat.rs
index 9fcafe206..e0fd01a1f 100644
--- a/src/chat.rs
+++ b/src/chat.rs
@@ -1745,11 +1745,12 @@ pub async fn get_chat_msgs(
 }
 
 pub async fn marknoticed_chat(context: &Context, chat_id: ChatId) -> Result<(), Error> {
+    // "WHERE" below uses the index `(state, hidden, chat_id)`, see get_fresh_msg_cnt() for reasoning
     if !context
         .sql
         .exists(
-            "SELECT id FROM msgs  WHERE chat_id=? AND state=?;",
-            paramsv![chat_id, MessageState::InFresh],
+            "SELECT id FROM msgs WHERE state=? AND hidden=0 AND chat_id=?;",
+            paramsv![MessageState::InFresh, chat_id],
         )
         .await?
     {
@@ -1760,10 +1761,11 @@ pub async fn marknoticed_chat(context: &Context, chat_id: ChatId) -> Result<(),
         .sql
         .execute(
             "UPDATE msgs
-            SET state=13
-          WHERE chat_id=?
-            AND state=10;",
-            paramsv![chat_id],
+            SET state=?
+          WHERE state=?
+            AND hidden=0
+            AND chat_id=?;",
+            paramsv![MessageState::InNoticed, MessageState::InFresh, chat_id],
         )
         .await?;
 
diff --git a/src/sql.rs b/src/sql.rs
index 8a3f47b9a..98fc7d21e 100644
--- a/src/sql.rs
+++ b/src/sql.rs
@@ -1360,7 +1360,7 @@ CREATE INDEX devmsglabels_index1 ON devmsglabels (label);
         }
         if dbversion < 68 {
             info!(context, "[migration] v68");
-            // the index is used to speed up get_fresh_msg_cnt(), see comment there for more details
+            // the index is used to speed up get_fresh_msg_cnt() (see comment there for more details) and marknoticed_chat()
             sql.execute(
                 "CREATE INDEX IF NOT EXISTS msgs_index7 ON msgs (state, hidden, chat_id);",
                 paramsv![],