drainer/* change more reasonable default config value (#439)

* drainer/* change more reasonable default config value

cmd/drainer/drainer.toml

@@ -28,10 +28,12 @@ pd-urls = "http://127.0.0.1:2379"
 ignore-schemas = "INFORMATION_SCHEMA,PERFORMANCE_SCHEMA,mysql"
 
 # number of binlog events in a transaction batch
-txn-batch = 1
+txn-batch = 20
 
 # work count to execute binlogs
-worker-count = 1
+# if the latency between drainer and downstream(mysql or tidb) are too high, you might want to increase this
+# to get higher throughput by higher concurrent write to the downstream
+worker-count = 16
 
 disable-dispatch = false
 
@@ -60,10 +62,9 @@ host = "127.0.0.1"
 user = "root"
 password = ""
 port = 3306
-# Time and size limits for flash batch write
-# time-limit = "30s"
-# size-limit = "100000"
+
 [syncer.to.checkpoint]
+# you can uncomment this to change the database to save checkpoint when the downstream is mysql or tidb
 #schema = "tidb_binlog"
 
 # Uncomment this if you want to use pb or sql as db-type.

drainer/config.go

@@ -100,9 +100,9 @@ func NewConfig() *Config {
 	fs.StringVar(&cfg.LogFile, "log-file", "", "log file path")
 	fs.StringVar(&cfg.LogRotate, "log-rotate", "", "log file rotate type, hour/day")
 	fs.Int64Var(&cfg.InitialCommitTS, "initial-commit-ts", 0, "if drainer donesn't have checkpoint, use initial commitTS to initial checkpoint")
-	fs.IntVar(&cfg.SyncerCfg.TxnBatch, "txn-batch", 1, "number of binlog events in a transaction batch")
+	fs.IntVar(&cfg.SyncerCfg.TxnBatch, "txn-batch", 20, "number of binlog events in a transaction batch")
 	fs.StringVar(&cfg.SyncerCfg.IgnoreSchemas, "ignore-schemas", "INFORMATION_SCHEMA,PERFORMANCE_SCHEMA,mysql", "disable sync those schemas")
-	fs.IntVar(&cfg.SyncerCfg.WorkerCount, "c", 1, "parallel worker count")
+	fs.IntVar(&cfg.SyncerCfg.WorkerCount, "c", 16, "parallel worker count")
 	fs.StringVar(&cfg.SyncerCfg.DestDBType, "dest-db-type", "mysql", "target db type: mysql or tidb or pb or flash or kafka; see syncer section in conf/drainer.toml")
 	fs.BoolVar(&cfg.SyncerCfg.DisableDispatch, "disable-dispatch", false, "disable dispatching sqls that in one same binlog; if set true, work-count and txn-batch would be useless")
 	fs.BoolVar(&cfg.SyncerCfg.SafeMode, "safe-mode", false, "enable safe mode to make syncer reentrant")