fix: ensure table route metadata is eventually rolled back on failure

src/meta-srv/src/procedure/region_migration.rs

@@ -12,6 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+pub(crate) mod close_downgraded_region;
 pub(crate) mod downgrade_leader_region;
 pub(crate) mod manager;
 pub(crate) mod migration_abort;
@@ -43,6 +44,7 @@ use common_procedure::error::{
     Error as ProcedureError, FromJsonSnafu, Result as ProcedureResult, ToJsonSnafu,
 };
 use common_procedure::{Context as ProcedureContext, LockKey, Procedure, Status, StringKey};
+use common_telemetry::info;
 use manager::RegionMigrationProcedureGuard;
 pub use manager::{
     RegionMigrationManagerRef, RegionMigrationProcedureTask, RegionMigrationProcedureTracker,
@@ -91,7 +93,9 @@ impl PersistentContext {
         let lock_key = vec![
             CatalogLock::Read(&self.catalog).into(),
             SchemaLock::read(&self.catalog, &self.schema).into(),
-            TableLock::Read(region_id.table_id()).into(),
+            // The optimistic updating of table route is not working very well,
+            // so we need to use the write lock here.
+            TableLock::Write(region_id.table_id()).into(),
             RegionLock::Write(region_id).into(),
         ];
 
@@ -253,7 +257,7 @@ impl Context {
                 .await
                 .context(error::TableMetadataManagerSnafu)
                 .map_err(BoxedError::new)
-                .context(error::RetryLaterWithSourceSnafu {
+                .with_context(|_| error::RetryLaterWithSourceSnafu {
                     reason: format!("Failed to get TableRoute: {table_id}"),
                 })?
                 .context(error::TableRouteNotFoundSnafu { table_id })?;
@@ -317,7 +321,7 @@ impl Context {
                 .await
                 .context(error::TableMetadataManagerSnafu)
                 .map_err(BoxedError::new)
-                .context(error::RetryLaterWithSourceSnafu {
+                .with_context(|_| error::RetryLaterWithSourceSnafu {
                     reason: format!("Failed to get TableInfo: {table_id}"),
                 })?
                 .context(error::TableInfoNotFoundSnafu { table_id })?;
@@ -350,7 +354,7 @@ impl Context {
                 .await
                 .context(error::TableMetadataManagerSnafu)
                 .map_err(BoxedError::new)
-                .context(error::RetryLaterWithSourceSnafu {
+                .with_context(|_| error::RetryLaterWithSourceSnafu {
                     reason: format!("Failed to get DatanodeTable: ({datanode_id},{table_id})"),
                 })?
                 .context(error::DatanodeTableNotFoundSnafu {
@@ -474,6 +478,48 @@ impl RegionMigrationProcedure {
             _guard: guard,
         })
     }
+
+    async fn rollback_inner(&mut self) -> Result<()> {
+        let _timer = METRIC_META_REGION_MIGRATION_EXECUTE
+            .with_label_values(&["rollback"])
+            .start_timer();
+
+        let table_id = self.context.region_id().table_id();
+        let region_id = self.context.region_id();
+        self.context.remove_table_route_value();
+        let table_metadata_manager = self.context.table_metadata_manager.clone();
+        let table_route = self.context.get_table_route_value().await?;
+
+        // Safety: It must be a physical table route.
+        let downgraded = table_route
+            .region_routes()
+            .unwrap()
+            .iter()
+            .filter(|route| route.region.id == region_id)
+            .any(|route| route.is_leader_downgrading());
+
+        if downgraded {
+            info!("Rollbacking downgraded region leader table route, region: {region_id}");
+            table_metadata_manager
+                    .update_leader_region_status(table_id, table_route, |route| {
+                        if route.region.id == region_id {
+                            Some(None)
+                        } else {
+                            None
+                        }
+                    })
+                    .await
+                    .context(error::TableMetadataManagerSnafu)
+                    .map_err(BoxedError::new)
+                    .with_context(|_| error::RetryLaterWithSourceSnafu {
+                        reason: format!("Failed to update the table route during the rollback downgraded leader region: {region_id}"),
+                    })?;
+        }
+
+        self.context.register_failure_detectors().await;
+
+        Ok(())
+    }
 }
 
 #[async_trait::async_trait]
@@ -482,6 +528,16 @@ impl Procedure for RegionMigrationProcedure {
         Self::TYPE_NAME
     }
 
+    async fn rollback(&mut self, _ctx: &ProcedureContext) -> ProcedureResult<()> {
+        self.rollback_inner()
+            .await
+            .map_err(ProcedureError::external)
+    }
+
+    fn rollback_supported(&self) -> bool {
+        true
+    }
+
     async fn execute(&mut self, _ctx: &ProcedureContext) -> ProcedureResult<Status> {
         let state = &mut self.state;
 
@@ -707,6 +763,12 @@ mod tests {
                 Assertion::simple(assert_update_metadata_upgrade, assert_no_persist),
             ),
             // UpdateMetadata::Upgrade
+            Step::next(
+                "Should be the close downgraded region",
+                None,
+                Assertion::simple(assert_close_downgraded_region, assert_no_persist),
+            ),
+            // CloseDowngradedRegion
             Step::next(
                 "Should be the region migration end",
                 None,
@@ -1077,6 +1139,12 @@ mod tests {
                 Assertion::simple(assert_update_metadata_upgrade, assert_no_persist),
             ),
             // UpdateMetadata::Upgrade
+            Step::next(
+                "Should be the close downgraded region",
+                None,
+                Assertion::simple(assert_close_downgraded_region, assert_no_persist),
+            ),
+            // CloseDowngradedRegion
             Step::next(
                 "Should be the region migration end",
                 None,

src/meta-srv/src/procedure/region_migration/close_downgraded_region.rs

@@ -0,0 +1,138 @@
+// Copyright 2023 Greptime Team
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+use std::any::Any;
+use std::time::Duration;
+
+use api::v1::meta::MailboxMessage;
+use common_meta::distributed_time_constants::MAILBOX_RTT_SECS;
+use common_meta::instruction::{Instruction, InstructionReply, SimpleReply};
+use common_meta::key::datanode_table::RegionInfo;
+use common_meta::RegionIdent;
+use common_procedure::Status;
+use common_telemetry::{info, warn};
+use serde::{Deserialize, Serialize};
+use snafu::ResultExt;
+
+use crate::error::{self, Result};
+use crate::handler::HeartbeatMailbox;
+use crate::procedure::region_migration::migration_end::RegionMigrationEnd;
+use crate::procedure::region_migration::{Context, State};
+use crate::service::mailbox::Channel;
+
+const CLOSE_DOWNGRADED_REGION_TIMEOUT: Duration = Duration::from_secs(MAILBOX_RTT_SECS);
+
+#[derive(Debug, Serialize, Deserialize)]
+pub struct CloseDowngradedRegion;
+
+#[async_trait::async_trait]
+#[typetag::serde]
+impl State for CloseDowngradedRegion {
+    async fn next(&mut self, ctx: &mut Context) -> Result<(Box<dyn State>, Status)> {
+        if let Err(err) = self.close_downgraded_leader_region(ctx).await {
+            let downgrade_leader_datanode = &ctx.persistent_ctx.from_peer;
+            let region_id = ctx.region_id();
+            warn!(err; "Failed to close downgraded leader region: {region_id} on datanode {:?}", downgrade_leader_datanode);
+        }
+
+        Ok((Box::new(RegionMigrationEnd), Status::done()))
+    }
+
+    fn as_any(&self) -> &dyn Any {
+        self
+    }
+}
+
+impl CloseDowngradedRegion {
+    /// Builds close region instruction.
+    ///
+    /// Abort(non-retry):
+    /// - Datanode Table is not found.
+    async fn build_close_region_instruction(&self, ctx: &mut Context) -> Result<Instruction> {
+        let pc = &ctx.persistent_ctx;
+        let downgrade_leader_datanode_id = pc.from_peer.id;
+        let cluster_id = pc.cluster_id;
+        let table_id = pc.region_id.table_id();
+        let region_number = pc.region_id.region_number();
+        let datanode_table_value = ctx.get_from_peer_datanode_table_value().await?;
+
+        let RegionInfo { engine, .. } = datanode_table_value.region_info.clone();
+
+        Ok(Instruction::CloseRegion(RegionIdent {
+            cluster_id,
+            datanode_id: downgrade_leader_datanode_id,
+            table_id,
+            region_number,
+            engine,
+        }))
+    }
+
+    /// Closes the downgraded leader region.
+    async fn close_downgraded_leader_region(&self, ctx: &mut Context) -> Result<()> {
+        let close_instruction = self.build_close_region_instruction(ctx).await?;
+        let region_id = ctx.region_id();
+        let pc = &ctx.persistent_ctx;
+        let downgrade_leader_datanode = &pc.from_peer;
+        let msg = MailboxMessage::json_message(
+            &format!("Close downgraded region: {}", region_id),
+            &format!("Meta@{}", ctx.server_addr()),
+            &format!(
+                "Datanode-{}@{}",
+                downgrade_leader_datanode.id, downgrade_leader_datanode.addr
+            ),
+            common_time::util::current_time_millis(),
+            &close_instruction,
+        )
+        .with_context(|_| error::SerializeToJsonSnafu {
+            input: close_instruction.to_string(),
+        })?;
+
+        let ch = Channel::Datanode(downgrade_leader_datanode.id);
+        let receiver = ctx
+            .mailbox
+            .send(&ch, msg, CLOSE_DOWNGRADED_REGION_TIMEOUT)
+            .await?;
+
+        match receiver.await? {
+            Ok(msg) => {
+                let reply = HeartbeatMailbox::json_reply(&msg)?;
+                info!(
+                    "Received close downgraded leade region reply: {:?}, region: {}",
+                    reply, region_id
+                );
+                let InstructionReply::CloseRegion(SimpleReply { result, error }) = reply else {
+                    return error::UnexpectedInstructionReplySnafu {
+                        mailbox_message: msg.to_string(),
+                        reason: "expect close region reply",
+                    }
+                    .fail();
+                };
+
+                if result {
+                    Ok(())
+                } else {
+                    error::UnexpectedSnafu {
+                        violated: format!(
+                            "Failed to close downgraded leader region: {region_id} on datanode {:?}, error: {error:?}",
+                            downgrade_leader_datanode,
+                        ),
+                    }
+                    .fail()
+                }
+            }
+
+            Err(e) => Err(e),
+        }
+    }
+}

src/meta-srv/src/procedure/region_migration/migration_start.rs

@@ -21,11 +21,11 @@ use serde::{Deserialize, Serialize};
 use snafu::{OptionExt, ResultExt};
 use store_api::storage::RegionId;
 
-use super::migration_abort::RegionMigrationAbort;
-use super::migration_end::RegionMigrationEnd;
-use super::open_candidate_region::OpenCandidateRegion;
-use super::update_metadata::UpdateMetadata;
 use crate::error::{self, Result};
+use crate::procedure::region_migration::migration_abort::RegionMigrationAbort;
+use crate::procedure::region_migration::migration_end::RegionMigrationEnd;
+use crate::procedure::region_migration::open_candidate_region::OpenCandidateRegion;
+use crate::procedure::region_migration::update_metadata::UpdateMetadata;
 use crate::procedure::region_migration::{Context, State};
 
 /// The behaviors:

src/meta-srv/src/procedure/region_migration/open_candidate_region.rs

@@ -25,9 +25,9 @@ use common_telemetry::info;
 use serde::{Deserialize, Serialize};
 use snafu::{OptionExt, ResultExt};
 
-use super::update_metadata::UpdateMetadata;
 use crate::error::{self, Result};
 use crate::handler::HeartbeatMailbox;
+use crate::procedure::region_migration::update_metadata::UpdateMetadata;
 use crate::procedure::region_migration::{Context, State};
 use crate::service::mailbox::Channel;
 
@@ -145,7 +145,10 @@ impl OpenCandidateRegion {
         match receiver.await? {
             Ok(msg) => {
                 let reply = HeartbeatMailbox::json_reply(&msg)?;
-                info!("Received open region reply: {:?}", reply);
+                info!(
+                    "Received open region reply: {:?}, region: {}",
+                    reply, region_id
+                );
                 let InstructionReply::OpenRegion(SimpleReply { result, error }) = reply else {
                     return error::UnexpectedInstructionReplySnafu {
                         mailbox_message: msg.to_string(),

src/meta-srv/src/procedure/region_migration/test_util.rs

@@ -44,19 +44,21 @@ use store_api::storage::RegionId;
 use table::metadata::RawTableInfo;
 use tokio::sync::mpsc::{Receiver, Sender};
 
-use super::manager::RegionMigrationProcedureTracker;
-use super::migration_abort::RegionMigrationAbort;
-use super::upgrade_candidate_region::UpgradeCandidateRegion;
-use super::{Context, ContextFactory, DefaultContextFactory, State, VolatileContext};
 use crate::cache_invalidator::MetasrvCacheInvalidator;
 use crate::error::{self, Error, Result};
 use crate::handler::{HeartbeatMailbox, Pusher, Pushers};
 use crate::metasrv::MetasrvInfo;
+use crate::procedure::region_migration::close_downgraded_region::CloseDowngradedRegion;
 use crate::procedure::region_migration::downgrade_leader_region::DowngradeLeaderRegion;
+use crate::procedure::region_migration::manager::RegionMigrationProcedureTracker;
+use crate::procedure::region_migration::migration_abort::RegionMigrationAbort;
 use crate::procedure::region_migration::migration_end::RegionMigrationEnd;
 use crate::procedure::region_migration::open_candidate_region::OpenCandidateRegion;
 use crate::procedure::region_migration::update_metadata::UpdateMetadata;
-use crate::procedure::region_migration::PersistentContext;
+use crate::procedure::region_migration::upgrade_candidate_region::UpgradeCandidateRegion;
+use crate::procedure::region_migration::{
+    Context, ContextFactory, DefaultContextFactory, PersistentContext, State, VolatileContext,
+};
 use crate::service::mailbox::{Channel, MailboxRef};
 
 pub type MockHeartbeatReceiver = Receiver<std::result::Result<HeartbeatResponse, tonic::Status>>;
@@ -569,6 +571,14 @@ pub(crate) fn assert_region_migration_end(next: &dyn State) {
     let _ = next.as_any().downcast_ref::<RegionMigrationEnd>().unwrap();
 }
 
+/// Asserts the [State] should be [CloseDowngradedRegion].
+pub(crate) fn assert_close_downgraded_region(next: &dyn State) {
+    let _ = next
+        .as_any()
+        .downcast_ref::<CloseDowngradedRegion>()
+        .unwrap();
+}
+
 /// Asserts the [State] should be [RegionMigrationAbort].
 pub(crate) fn assert_region_migration_abort(next: &dyn State) {
     let _ = next

src/meta-srv/src/procedure/region_migration/update_metadata.rs

@@ -22,10 +22,10 @@ use common_procedure::Status;
 use common_telemetry::warn;
 use serde::{Deserialize, Serialize};
 
-use super::migration_abort::RegionMigrationAbort;
-use super::migration_end::RegionMigrationEnd;
 use crate::error::Result;
+use crate::procedure::region_migration::close_downgraded_region::CloseDowngradedRegion;
 use crate::procedure::region_migration::downgrade_leader_region::DowngradeLeaderRegion;
+use crate::procedure::region_migration::migration_abort::RegionMigrationAbort;
 use crate::procedure::region_migration::{Context, State};
 
 #[derive(Debug, Serialize, Deserialize)]
@@ -58,7 +58,7 @@ impl State for UpdateMetadata {
                 if let Err(err) = ctx.invalidate_table_cache().await {
                     warn!("Failed to broadcast the invalidate table cache message during the upgrade candidate, error: {err:?}");
                 };
-                Ok((Box::new(RegionMigrationEnd), Status::done()))
+                Ok((Box::new(CloseDowngradedRegion), Status::executing(false)))
             }
             UpdateMetadata::Rollback => {
                 self.rollback_downgraded_region(ctx).await?;