java.lang.RuntimeException: One or more fetchers have encountered exception

Describe the bug(Please use English) ERROR MESSAGE: `java.lang.RuntimeException: One or more fetchers have encountered exception at org.apache.flink.connector.base.source.reader.fetcher.SplitFetcherManager.checkErrors(SplitFetcherManager.java:223) at org.apache.flink.connector.base.source.reader.SourceReaderBase.getNextFetch(SourceReaderBase.java:154) at org.apache.flink.connector.base.source.reader.SourceReaderBase.pollNext(SourceReaderBase.java:116) at org.apache.flink.streaming.api.operators.SourceOperator.emitNext(SourceOperator.java:305) at org.apache.flink.streaming.runtime.io.StreamTaskSourceInput.emitNext(StreamTaskSourceInput.java:69) at org.apache.flink.streaming.runtime.io.StreamOneInputProcessor.processInput(StreamOneInputProcessor.java:66) at org.apache.flink.streaming.runtime.tasks.StreamTask.processInput(StreamTask.java:423) at org.apache.flink.streaming.runtime.tasks.mailbox.MailboxProcessor.runMailboxLoop(MailboxProcessor.java:204) at org.apache.flink.streaming.runtime.tasks.StreamTask.runMailboxLoop(StreamTask.java:684) at org.apache.flink.streaming.runtime.tasks.StreamTask.executeInvoke(StreamTask.java:639) at org.apache.flink.streaming.runtime.tasks.StreamTask.runWithCleanUpOnFail(StreamTask.java:650) at org.apache.flink.streaming.runtime.tasks.StreamTask.invoke(StreamTask.java:623) at org.apache.flink.runtime.taskmanager.Task.doRun(Task.java:779) at org.apache.flink.runtime.taskmanager.Task.run(Task.java:566) at java.lang.Thread.run(Thread.java:750) Caused by: java.lang.RuntimeException: SplitFetcher thread 31 received unexpected exception while polling the records at org.apache.flink.connector.base.source.reader.fetcher.SplitFetcher.runOnce(SplitFetcher.java:148) at org.apache.flink.connector.base.source.reader.fetcher.SplitFetcher.run(SplitFetcher.java:103) at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) at java.util.concurrent.FutureTask.run(FutureTask.java:266) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) … 1 more Caused by: io.debezium.DebeziumException: Error reading MySQL variables: Communications link failure

The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server. at io.debezium.connector.mysql.MySqlConnection.querySystemVariables(MySqlConnection.java:139) at io.debezium.connector.mysql.MySqlConnection.readMySqlSystemVariables(MySqlConnection.java:119) at io.debezium.connector.mysql.MySqlConnection.isTableIdCaseSensitive(MySqlConnection.java:429) at com.ververica.cdc.connectors.mysql.debezium.task.context.StatefulTaskContext.configure(StatefulTaskContext.java:102) at com.ververica.cdc.connectors.mysql.debezium.reader.SnapshotSplitReader.submitSplit(SnapshotSplitReader.java:93) at com.ververica.cdc.connectors.mysql.debezium.reader.SnapshotSplitReader.submitSplit(SnapshotSplitReader.java:64) at com.ververica.cdc.connectors.mysql.source.reader.MySqlSplitReader.checkSplitOrStartNext(MySqlSplitReader.java:163) at com.ververica.cdc.connectors.mysql.source.reader.MySqlSplitReader.fetch(MySqlSplitReader.java:73) at org.apache.flink.connector.base.source.reader.fetcher.FetchTask.run(FetchTask.java:56) at org.apache.flink.connector.base.source.reader.fetcher.SplitFetcher.runOnce(SplitFetcher.java:140) … 6 more Caused by: com.mysql.cj.jdbc.exceptions.CommunicationsException: Communications link failure

The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server. at com.mysql.cj.jdbc.exceptions.SQLError.createCommunicationsException(SQLError.java:174) at com.mysql.cj.jdbc.exceptions.SQLExceptionsMapping.translateException(SQLExceptionsMapping.java:64) at com.mysql.cj.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:836) at com.mysql.cj.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:456) at com.mysql.cj.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:246) at com.mysql.cj.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:197) at io.debezium.jdbc.JdbcConnection.lambda$patternBasedFactory$1(JdbcConnection.java:231) at io.debezium.jdbc.JdbcConnection.connection(JdbcConnection.java:872) at io.debezium.connector.mysql.MySqlConnection.connection(MySqlConnection.java:79) at io.debezium.jdbc.JdbcConnection.connection(JdbcConnection.java:867) at io.debezium.jdbc.JdbcConnection.query(JdbcConnection.java:550) at io.debezium.jdbc.JdbcConnection.query(JdbcConnection.java:498) at io.debezium.connector.mysql.MySqlConnection.querySystemVariables(MySqlConnection.java:125) … 15 more Caused by: com.mysql.cj.exceptions.CJCommunicationsException: Communications link failure

The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server. at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62) at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) at java.lang.reflect.Constructor.newInstance(Constructor.java:423) at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:61) at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:105) at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:151) at com.mysql.cj.exceptions.ExceptionFactory.createCommunicationsException(ExceptionFactory.java:167) at com.mysql.cj.protocol.a.NativeProtocol.readMessage(NativeProtocol.java:538) at com.mysql.cj.protocol.a.NativeProtocol.checkErrorMessage(NativeProtocol.java:702) at com.mysql.cj.protocol.a.NativeProtocol.sendCommand(NativeProtocol.java:641) at com.mysql.cj.protocol.a.NativeProtocol.sendCommand(NativeProtocol.java:128) at com.mysql.cj.NativeSession.sendCommand(NativeSession.java:311) at com.mysql.cj.NativeSession.loadServerVariables(NativeSession.java:764) at com.mysql.cj.jdbc.ConnectionImpl.initializePropsFromServer(ConnectionImpl.java:1298) at com.mysql.cj.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:967) at com.mysql.cj.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:826) … 25 more Caused by: java.net.SocketException: Connection timed out (Read failed) at java.net.SocketInputStream.socketRead0(Native Method) at java.net.SocketInputStream.socketRead(SocketInputStream.java:116) at java.net.SocketInputStream.read(SocketInputStream.java:171) at java.net.SocketInputStream.read(SocketInputStream.java:141) at com.mysql.cj.protocol.ReadAheadInputStream.fill(ReadAheadInputStream.java:107) at com.mysql.cj.protocol.ReadAheadInputStream.readFromUnderlyingStreamIfNecessary(ReadAheadInputStream.java:150) at com.mysql.cj.protocol.ReadAheadInputStream.read(ReadAheadInputStream.java:180) at java.io.FilterInputStream.read(FilterInputStream.java:133) at com.mysql.cj.protocol.FullReadInputStream.readFully(FullReadInputStream.java:64) at com.mysql.cj.protocol.a.SimplePacketReader.readHeader(SimplePacketReader.java:63) at com.mysql.cj.protocol.a.SimplePacketReader.readHeader(SimplePacketReader.java:45) at com.mysql.cj.protocol.a.TimeTrackingPacketReader.readHeader(TimeTrackingPacketReader.java:52) at com.mysql.cj.protocol.a.TimeTrackingPacketReader.readHeader(TimeTrackingPacketReader.java:41) at com.mysql.cj.protocol.a.MultiPacketReader.readHeader(MultiPacketReader.java:54) at com.mysql.cj.protocol.a.MultiPacketReader.readHeader(MultiPacketReader.java:44) at com.mysql.cj.protocol.a.NativeProtocol.readMessage(NativeProtocol.java:532) … 33 more ` Environment :

• Flink version : 1.14.3
• Flink CDC version: 2.2.0
• Database and version: MYSQL 8.0.15

To Reproduce Steps to reproduce the behavior:

1. Thes test data :
2. The test code :
3. The error :

Additional Description 同步整库数据，全量阶段Flink频繁报这个错误。