changefeed (ticdc): fix data lost when pause and resume changefeed wh…

…ile executing DDL. (#7683)

close #7682

cdc/owner/changefeed.go

@@ -492,6 +492,12 @@ LOOP:
 		return errors.Trace(err)
 	}
 
+	// we must clean cached ddl and tables in changefeed initialization
+	// otherwise, the changefeed will loss tables that are needed to be replicated
+	// ref: https://github.com/pingcap/tiflow/issues/7682
+	c.ddlEventCache = nil
+	c.currentTables = nil
+
 	cancelCtx, cancel := cdcContext.WithCancel(ctx)
 	c.cancel = cancel
 
@@ -609,7 +615,9 @@ func (c *changefeed) releaseResources(ctx cdcContext.Context) {
 	log.Info("changefeed closed",
 		zap.String("namespace", c.id.Namespace),
 		zap.String("changefeed", c.id.ID),
-		zap.Stringer("info", c.state.Info), zap.Bool("isRemoved", c.isRemoved))
+		zap.Any("status", c.state.Status),
+		zap.Stringer("info", c.state.Info),
+		zap.Bool("isRemoved", c.isRemoved))
 }
 
 func (c *changefeed) cleanupMetrics() {

tests/integration_tests/batch_update_to_no_batch/run.sh

@@ -44,7 +44,7 @@ function run() {
 	# pause changefeed
 	run_cdc_cli changefeed pause -c ${changefeed_id}
 	# update changefeed to no batch dml mode
-	run_cdc_cli changefeed update -c ${changefeed_id} --sink-uri="mysql://root@127.0.0.1:3306/?batch-dml-enable=true" --no-confirm
+	run_cdc_cli changefeed update -c ${changefeed_id} --sink-uri="mysql://root@127.0.0.1:3306/?batch-dml-enable=false" --no-confirm
 	# resume changefeed
 	run_cdc_cli changefeed resume -c ${changefeed_id}
 
@@ -53,7 +53,7 @@ function run() {
 	# pause changefeed
 	run_cdc_cli changefeed pause -c ${changefeed_id}
 	# update changefeed to no batch dml mode
-	run_cdc_cli changefeed update -c ${changefeed_id} --sink-uri="mysql://root@127.0.0.1:3306/?batch-dml-enable=false" --no-confirm
+	run_cdc_cli changefeed update -c ${changefeed_id} --sink-uri="mysql://root@127.0.0.1:3306/?batch-dml-enable=true" --no-confirm
 	# resume changefeed
 	run_cdc_cli changefeed resume -c ${changefeed_id}