drainer: skip 'alter table cache|nocache' DDL jobs (#1115)

close pingcap/tidb#31105

drainer/schema.go

@@ -315,6 +315,8 @@ func skipUnsupportedDDLJob(job *model.Job) bool {
 	// 	return true
 	case model.ActionLockTable, model.ActionUnlockTable:
 		return true
+	case model.ActionAlterCacheTable, model.ActionAlterNoCacheTable:
+		return true
 	case model.ActionAlterTableAttributes, model.ActionAlterTablePartitionAttributes:
 		return true
 	}

tests/cache_table/drainer.toml

@@ -0,0 +1,17 @@
+data-dir = '/tmp/tidb_binlog_test/data.drainer'
+
+[syncer]
+txn-batch = 1
+worker-count = 1
+safe-mode = false
+db-type = 'mysql'
+replicate-do-db = ['cache_test']
+
+[syncer.to]
+host = '127.0.0.1'
+user = 'root'
+password = ''
+port = 3306
+
+[syncer.to.checkpoint]
+schema = "cache_table_checkpoint"

tests/cache_table/run.sh

@@ -0,0 +1,28 @@
+#!/bin/sh
+
+set -e
+
+cd "$(dirname "$0")"
+
+run_drainer &
+
+sleep 3
+
+run_sql 'CREATE DATABASE cache_test;'
+run_sql 'CREATE TABLE cache_test.t1( a int, b varchar(128));'
+run_sql "INSERT INTO cache_test.t1 (a,b) VALUES(1,'a'),(2,'b'),(3,'c'),(4,'d');"
+run_sql "ALTER TABLE cache_test.t1 CACHE;"
+run_sql "INSERT INTO cache_test.t1 (a,b) VALUES(5,'e'),(6,'f'),(7,'g'),(8,'h');"
+run_sql "ALTER TABLE cache_test.t1 NOCACHE"
+
+sleep 3
+
+down_run_sql 'SELECT a, b FROM cache_test.t1 order by a'
+check_contains 'a: 7'
+check_contains 'b: g'
+check_contains 'a: 8'
+check_contains 'b: h'
+
+run_sql 'DROP DATABASE cache_test'
+
+killall drainer