From 2b4fa7fbe0bf475b8d1376ed544684920773f601 Mon Sep 17 00:00:00 2001
From: Jay Lee <BusyJayLee@gmail.com>
Date: Sat, 28 Aug 2021 01:24:17 +0800
Subject: [PATCH] allow skip writing commit index

Signed-off-by: Jay Lee <BusyJayLee@gmail.com>
---
 components/raftstore/src/store/config.rs       |  2 ++
 components/raftstore/src/store/fsm/store.rs    |  5 +++++
 components/raftstore/src/store/peer_storage.rs | 13 ++++++++++++-
 tests/integrations/config/mod.rs               |  1 +
 4 files changed, 20 insertions(+), 1 deletion(-)

diff --git a/components/raftstore/src/store/config.rs b/components/raftstore/src/store/config.rs
index 7b3a1ddf96e..30aefdecd30 100644
--- a/components/raftstore/src/store/config.rs
+++ b/components/raftstore/src/store/config.rs
@@ -177,6 +177,7 @@ pub struct Config {
     pub apply_yield_duration: ReadableDuration,
     #[config(skip)]
     pub disable_kv_wal: bool,
+    pub skip_write_commit_index: bool,
     pub enable_propose_batch: bool,
     pub skip_header: bool,
 
@@ -265,6 +266,7 @@ impl Default for Config {
             dev_assert: false,
             apply_yield_duration: ReadableDuration::millis(500),
             disable_kv_wal: false,
+            skip_write_commit_index: false,
             enable_propose_batch: true,
             skip_header: false,
 
diff --git a/components/raftstore/src/store/fsm/store.rs b/components/raftstore/src/store/fsm/store.rs
index fa147aa5cb6..64a8b2b2487 100644
--- a/components/raftstore/src/store/fsm/store.rs
+++ b/components/raftstore/src/store/fsm/store.rs
@@ -403,6 +403,11 @@ where
     fn set_sync_log(&mut self, sync: bool) {
         self.sync_log = sync;
     }
+
+    #[inline]
+    fn skip_write_commit_index(&self) -> bool {
+        self.cfg.skip_write_commit_index
+    }
 }
 
 impl<EK, ER, T> PollContext<EK, ER, T>
diff --git a/components/raftstore/src/store/peer_storage.rs b/components/raftstore/src/store/peer_storage.rs
index 54cc955f8ec..7991e020c99 100644
--- a/components/raftstore/src/store/peer_storage.rs
+++ b/components/raftstore/src/store/peer_storage.rs
@@ -398,6 +398,7 @@ where
     fn raft_wb_mut(&mut self) -> &mut WR;
     fn sync_log(&self) -> bool;
     fn set_sync_log(&mut self, sync: bool);
+    fn skip_write_commit_index(&self) -> bool;
 }
 
 fn storage_error<E>(error: E) -> raft::Error
@@ -1549,9 +1550,16 @@ where
                 ctx.raft_state.set_hard_state(hs.clone());
             }
         }
+        let new_commit = ctx.raft_state.get_hard_state().get_commit();
+        if ready_ctx.skip_write_commit_index() {
+            let old_commit = self.raft_state.get_hard_state().get_commit();
+            ctx.raft_state.mut_hard_state().set_commit(old_commit);
+        }
+        let skip_write = ctx.raft_state == self.raft_state;
+        ctx.raft_state.mut_hard_state().set_commit(new_commit);
 
         // Save raft state if it has changed or there is a snapshot.
-        if ctx.raft_state != self.raft_state || snapshot_index > 0 {
+        if !skip_write || snapshot_index > 0 {
             ctx.save_raft_state_to(ready_ctx.raft_wb_mut())?;
             if snapshot_index > 0 {
                 // in case of restart happen when we just write region state to Applying,
@@ -1950,6 +1958,9 @@ mod tests {
         fn set_sync_log(&mut self, sync: bool) {
             self.sync_log = sync;
         }
+        fn skip_write_commit_index(&self) -> bool {
+            false
+        }
     }
 
     fn new_storage_from_ents(
diff --git a/tests/integrations/config/mod.rs b/tests/integrations/config/mod.rs
index 90f7a46edcc..3f95a2f8953 100644
--- a/tests/integrations/config/mod.rs
+++ b/tests/integrations/config/mod.rs
@@ -207,6 +207,7 @@ fn test_serde_custom_tikv_config() {
         future_poll_size: 2,
         hibernate_regions: false,
         disable_kv_wal: true,
+        skip_write_commit_index: false,
         dev_assert: true,
         apply_yield_duration: ReadableDuration::millis(333),
         perf_level: PerfLevel::EnableTime,