Flink CDC 3.0 Starrocks建表失敗會導致任務卡主！

現(xiàn)象

StarRocks建表失敗，然后任務自動重啟，重啟完畢后數(shù)據回放，jobMaster打印下面日志后，整個任務會卡主

There are already processing requests. Wait for processing

原因分析

前提概要：可以先閱讀CDC表變更處理流程然后再讀下面會更加清晰

涉及類包括SchemaRegistry、SchemaOperator和StarRocksMetadataApplier類

SchemaRegistry->handleEventFromOperator方法執(zhí)行建表失敗后會導致任務重啟，但是jobMaster不會重啟，因此SchemaRegistry.requestHandler.pendingSchemaChanges無法刪除導致任務卡主！

public void flushSuccess(TableId tableId, int sinkSubtask) {flushedSinkWriters.add(sinkSubtask);if (flushedSinkWriters.equals(activeSinkWriters)) {LOG.info("All sink subtask have flushed for table {}. Start to apply schema change.",tableId.toString());PendingSchemaChange waitFlushSuccess = pendingSchemaChanges.get(0);//執(zhí)行表結構變更操作！applySchemaChange(tableId, waitFlushSuccess.getChangeRequest().getSchemaChangeEvent());waitFlushSuccess.getResponseFuture().complete(wrap(new ReleaseUpstreamResponse()));if (RECEIVED_RELEASE_REQUEST.equals(waitFlushSuccess.getStatus())) {//異常會跳過刪除pendingSchame！startNextSchemaChangeRequest();}}
}
//刪除pendingSchemaChanges中已經完成的pendingSchame
private void startNextSchemaChangeRequest() {this.pendingSchemaChanges.remove(0);this.flushedSinkWriters.clear();...
}public CompletableFuture<CoordinationResponse> handleSchemaChangeRequest(SchemaChangeRequest request) {//歷史pendingSchame未刪除導致，卡主if (pendingSchemaChanges.isEmpty()) {LOG.info("Received schema change event request from table {}. Start to buffer requests for others.",request.getTableId().toString());if (request.getSchemaChangeEvent() instanceof CreateTableEvent&& schemaManager.schemaExists(request.getTableId())) {return CompletableFuture.completedFuture(wrap(new SchemaChangeResponse(false)));}CompletableFuture<CoordinationResponse> response =CompletableFuture.completedFuture(wrap(new SchemaChangeResponse(true)));schemaManager.applySchemaChange(request.getSchemaChangeEvent());pendingSchemaChanges.add(new PendingSchemaChange(request, response));pendingSchemaChanges.get(0).startToWaitForReleaseRequest();return response;} else {LOG.info("There are already processing requests. Wait for processing.");CompletableFuture<CoordinationResponse> response = new CompletableFuture<>();pendingSchemaChanges.add(new PendingSchemaChange(request, response));return response;}
}

解決辦法

1. 讓建表執(zhí)行成功
2. catch住異常，將schame刪除后再異常重啟（未驗證）