2019-09-19 08:30:18,347 INFO   Postgres|audit|records-stream-producer  Different column count 4 present in the server message as schema in memory contains 3; refreshing table schema   [io.debezium.connector.postgresql.RecordsStreamProducer]
2019-09-19 08:30:18,467 ERROR  Postgres|audit|records-stream-producer  Failed to properly convert key value for 'schema.a_table.a_column' of type varchar for row [50, 424439ef-bb53-455f-a9cd-fbb228f477e8, null, null]:   [io.debezium.relational.TableSchemaBuilder]
org.apache.kafka.connect.errors.DataException: Invalid value: null used for required field: "a_column", schema type: STRING
	at org.apache.kafka.connect.data.ConnectSchema.validateValue(ConnectSchema.java:220)
	at org.apache.kafka.connect.data.Struct.put(Struct.java:216)
	at io.debezium.relational.TableSchemaBuilder.lambda$createKeyGenerator$1(TableSchemaBuilder.java:174)
	at io.debezium.relational.TableSchema.keyFromColumnData(TableSchema.java:124)
	at io.debezium.connector.postgresql.RecordsStreamProducer.generateUpdateRecord(RecordsStreamProducer.java:325)
	at io.debezium.connector.postgresql.RecordsStreamProducer.process(RecordsStreamProducer.java:264)
	at io.debezium.connector.postgresql.RecordsStreamProducer.lambda$streamChanges$1(RecordsStreamProducer.java:133)
	at io.debezium.connector.postgresql.connection.wal2json.NonStreamingWal2JsonMessageDecoder.processMessage(NonStreamingWal2JsonMessageDecoder.java:62)
	at io.debezium.connector.postgresql.connection.PostgresReplicationConnection$1.deserializeMessages(PostgresReplicationConnection.java:269)
	at io.debezium.connector.postgresql.connection.PostgresReplicationConnection$1.read(PostgresReplicationConnection.java:254)
	at io.debezium.connector.postgresql.RecordsStreamProducer.streamChanges(RecordsStreamProducer.java:133)
	at io.debezium.connector.postgresql.RecordsStreamProducer.lambda$start$0(RecordsStreamProducer.java:119)
	at java.util.concurrent.Executors$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$Worker.run(ThreadPoolExecutor.java:624)
	at java.lang.Thread.run(Thread.java:748)
2019-09-19 08:30:18,556 WARN   ||  [Producer clientId=producer-5] Error while fetching metadata with correlation id 41 : {audit.topic1=LEADER_NOT_AVAILABLE}   [org.apache.kafka.clients.NetworkClient]
2019-09-19 08:30:18,711 WARN   ||  [Producer clientId=producer-5] Error while fetching metadata with correlation id 43 : {audit.topic2=LEADER_NOT_AVAILABLE}   [org.apache.kafka.clients.NetworkClient]
2019-09-19 08:30:18,830 INFO   ||  WorkerSourceTask{id=debezium-connector-0} Committing offsets   [org.apache.kafka.connect.runtime.WorkerSourceTask]
2019-09-19 08:30:18,831 INFO   ||  WorkerSourceTask{id=debezium-connector-0} flushing 2 outstanding messages for offset commit   [org.apache.kafka.connect.runtime.WorkerSourceTask]
2019-09-19 08:30:18,944 INFO   ||  WorkerSourceTask{id=debezium-connector-0} Finished commitOffsets successfully in 109 ms   [org.apache.kafka.connect.runtime.WorkerSourceTask]
2019-09-19 08:30:18,952 ERROR  ||  WorkerSourceTask{id=debezium-connector-0} Task threw an uncaught and unrecoverable exception   [org.apache.kafka.connect.runtime.WorkerTask]
org.apache.kafka.connect.errors.ConnectException: Tolerance exceeded in error handler
	at org.apache.kafka.connect.runtime.errors.RetryWithToleranceOperator.execAndHandleError(RetryWithToleranceOperator.java:178)
	at org.apache.kafka.connect.runtime.errors.RetryWithToleranceOperator.execute(RetryWithToleranceOperator.java:104)
	at org.apache.kafka.connect.runtime.WorkerSourceTask.convertTransformedRecord(WorkerSourceTask.java:267)
	at org.apache.kafka.connect.runtime.WorkerSourceTask.sendRecords(WorkerSourceTask.java:294)
	at org.apache.kafka.connect.runtime.WorkerSourceTask.execute(WorkerSourceTask.java:229)
	at org.apache.kafka.connect.runtime.WorkerTask.doRun(WorkerTask.java:175)
	at org.apache.kafka.connect.runtime.WorkerTask.run(WorkerTask.java:219)
	at java.util.concurrent.Executors$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$Worker.run(ThreadPoolExecutor.java:624)
	at java.lang.Thread.run(Thread.java:748)
Caused by: org.apache.kafka.connect.errors.DataException: Conversion error: null value for field that is required and has no default value
	at org.apache.kafka.connect.json.JsonConverter.convertToJson(JsonConverter.java:589)
	at org.apache.kafka.connect.json.JsonConverter.convertToJson(JsonConverter.java:683)
	at org.apache.kafka.connect.json.JsonConverter.convertToJsonWithEnvelope(JsonConverter.java:570)
	at org.apache.kafka.connect.json.JsonConverter.fromConnectData(JsonConverter.java:324)
	at org.apache.kafka.connect.runtime.WorkerSourceTask.lambda$convertTransformedRecord$1(WorkerSourceTask.java:267)
	at org.apache.kafka.connect.runtime.errors.RetryWithToleranceOperator.execAndRetry(RetryWithToleranceOperator.java:128)
	at org.apache.kafka.connect.runtime.errors.RetryWithToleranceOperator.execAndHandleError(RetryWithToleranceOperator.java:162)
	... 11 more