ClientAdapter(Sync RDB)同步至Postgres，如果canalAdapters

软件清单： canal.deployer-1.1.1 canal.adapter-1.1.3

问题描述： 使用ClientAdapter(Sync RDB)同步至Postgres数据库，如果canal.adapter/conf/application.yml中canalAdapters参数设置多个instance和groups，RdbSyncService会报异常ConcurrentModificationException，而如果只保留一个就没问题，请问有可能是什么原因，谢谢。

异常信息：

2019-07-10 10:50:24.794 [pool-10-thread-1] ERROR c.a.o.canal.adapter.launcher.loader.CanalAdapterWorker - java.lang.RuntimeException: java.util.concurrent.ExecutionException: java.lang.Ru ntimeException: java.util.ConcurrentModificationException java.lang.RuntimeException: java.lang.RuntimeException: java.util.concurrent.ExecutionException: java.lang.RuntimeException: java.util.ConcurrentModificationException at com.alibaba.otter.canal.client.adapter.rdb.RdbAdapter.sync(RdbAdapter.java:169) at com.alibaba.otter.canal.adapter.launcher.loader.AbstractCanalAdapterWorker.batchSync(AbstractCanalAdapterWorker.java:198) at com.alibaba.otter.canal.adapter.launcher.loader.AbstractCanalAdapterWorker.lambda$null$1(AbstractCanalAdapterWorker.java:62) at java.util.ArrayList.forEach(ArrayList.java:1257) at com.alibaba.otter.canal.adapter.launcher.loader.AbstractCanalAdapterWorker.lambda$null$2(AbstractCanalAdapterWorker.java:58) at java.util.concurrent.FutureTask.run(FutureTask.java:266) at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) at java.lang.Thread.run(Thread.java:748) Caused by: java.lang.RuntimeException: java.util.concurrent.ExecutionException: java.lang.RuntimeException: java.util.ConcurrentModificationException at com.alibaba.otter.canal.client.adapter.rdb.service.RdbSyncService.lambda$sync$2(RdbSyncService.java:127) at java.util.ArrayList.forEach(ArrayList.java:1257) at com.alibaba.otter.canal.client.adapter.rdb.service.RdbSyncService.sync(RdbSyncService.java:123) at com.alibaba.otter.canal.client.adapter.rdb.service.RdbSyncService.sync(RdbSyncService.java:147) at com.alibaba.otter.canal.client.adapter.rdb.RdbAdapter.sync(RdbAdapter.java:166) ... 8 common frames omitted Caused by: java.util.concurrent.ExecutionException: java.lang.RuntimeException: java.util.ConcurrentModificationException at java.util.concurrent.FutureTask.report(FutureTask.java:122) at java.util.concurrent.FutureTask.get(FutureTask.java:192) at com.alibaba.otter.canal.client.adapter.rdb.service.RdbSyncService.lambda$sync$2(RdbSyncService.java:125) ... 12 common frames omitted Caused by: java.lang.RuntimeException: java.util.ConcurrentModificationException at com.alibaba.otter.canal.client.adapter.rdb.service.RdbSyncService.lambda$sync$1(RdbSyncService.java:118) ... 4 common frames omitted Caused by: java.util.ConcurrentModificationException: null at java.util.ArrayList.forEach(ArrayList.java:1260) at com.alibaba.otter.canal.client.adapter.rdb.service.RdbSyncService.lambda$sync$1(RdbSyncService.java:110) ... 4 common frames omitted 2019-07-10 10:50:24.794 [Thread-8] ERROR c.a.o.canal.adapter.launcher.loader.CanalAdapterWorker - Outer adapter sync failed! Error sync but ACK!

原提问者GitHub用户dingqianlong