From b461bfc2d77115219a5ee948140f35b21af44372 Mon Sep 17 00:00:00 2001
From: noname0443 <noname342341@gmail.com>
Date: Tue, 17 Sep 2024 15:38:13 +0300
Subject: [PATCH] Fix switchover when many connection appear

---
 README.md                      |  1 +
 internal/app/app.go            | 15 +++++++++++++++
 internal/config/config.go      |  2 ++
 tests/images/mysql/mysync.yaml |  1 +
 4 files changed, 19 insertions(+)

diff --git a/README.md b/README.md
index 2b9e6159..7619bf50 100644
--- a/README.md
+++ b/README.md
@@ -116,6 +116,7 @@ replication_repair_max_attempts: 3
 
 external_replication_type: off
 show_only_gtid_diff: False
+force_switchover: False
 ```
 
 ### Usage
diff --git a/internal/app/app.go b/internal/app/app.go
index 02f79fe4..f143eb48 100644
--- a/internal/app/app.go
+++ b/internal/app/app.go
@@ -1208,6 +1208,21 @@ func (app *App) performSwitchover(clusterState map[string]*NodeState, activeNode
 		}
 		node := app.cluster.Get(host)
 		// in case node is a master
+
+		if app.config.ForceSwitchover {
+			err := node.SetOffline()
+			if err != nil {
+				app.logger.Infof("switchover: failed to set node %s offline: %v", host, err)
+				return fmt.Errorf("failed to set node %s read-only: %v", host, err)
+			}
+
+			err = node.SemiSyncDisable()
+			if err != nil {
+				app.logger.Infof("switchover: failed to disable semi-sync on node %s: %v", host, err)
+				return fmt.Errorf("failed to set node %s read-only: %v", host, err)
+			}
+		}
+
 		err := node.SetReadOnly(true)
 		if err != nil || app.emulateError("freeze_ro") {
 			app.logger.Infof("switchover: failed to set node %s read-only, trying kill bad queries: %v", host, err)
diff --git a/internal/config/config.go b/internal/config/config.go
index 21b00332..d4d3c8d6 100644
--- a/internal/config/config.go
+++ b/internal/config/config.go
@@ -97,6 +97,7 @@ type Config struct {
 	ReplMonErrorWaitInterval                time.Duration                `config:"repl_mon_error_wait_interval" yaml:"repl_mon_error_wait_interval"`
 	ReplMonSlaveWaitInterval                time.Duration                `config:"repl_mon_slave_wait_interval" yaml:"repl_mon_slave_wait_interval"`
 	ShowOnlyGTIDDiff                        bool                         `config:"show_only_gtid_diff" yaml:"show_only_gtid_diff"`
+	ForceSwitchover                         bool                         `config:"force_switchover" yaml:"force_switchover"`
 }
 
 // DefaultConfig returns default configuration for MySync
@@ -182,6 +183,7 @@ func DefaultConfig() (Config, error) {
 		ReplMonErrorWaitInterval:                10 * time.Second,
 		ReplMonSlaveWaitInterval:                10 * time.Second,
 		ShowOnlyGTIDDiff:                        false,
+		ForceSwitchover:                         false,
 	}
 	return config, nil
 }
diff --git a/tests/images/mysql/mysync.yaml b/tests/images/mysql/mysync.yaml
index a2a47a3d..72a8cd60 100644
--- a/tests/images/mysql/mysync.yaml
+++ b/tests/images/mysql/mysync.yaml
@@ -62,3 +62,4 @@ replication_channel: ''
 external_replication_type: 'external'
 show_only_gtid_diff: false
 repl_mon: ${REPL_MON:-false}
+force_switchover: false