[FLINK-38139] Fix consecutive online schema change causes job failure. #4064
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yuxiqian
reviewed
Jul 25, 2025
| private static final Pattern OSC_TABLE_ID_PATTERN = Pattern.compile("^_(.*)_(gho|new)$"); | ||
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| private static final Pattern OSC_TEMP_TABLE_ID_PATTERN = Pattern.compile("^_(.*)_(del|old)$"); | ||
| private static final Pattern RDS_OGT_TEMP_TABLE_ID_PATTERN = |
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We may want to support RDS OGT later as it could not be tested now.
czy006
reviewed
Aug 4, 2025
| Optional<String> finishedTables = | ||
| RecordUtils.parseOnLineSchemaRenameEvent(event.getRecord()); | ||
| if (finishedTables.isPresent()) { | ||
| TableId tableId = RecordUtils.getTableId(event.getRecord()); |
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When execute gh-ost /gh-ost --user="root" --password="XXXX" --host="localhost" --database="dinky" --table="dinky_user" --alter="ADD COLUMN czy04 DATETIME NULL AFTER update_time" --allow-on-master --ok-to-drop-table --initially-drop-ghost-table --initially-drop-old-table --execute,Have this error schema can't remove on BinlogSplitReader. pendingSchemaChangeEvents
If have del table,RecordUtils.getTableId have ',' with del and finishedTable.That will error record to ddl remove
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2025-08-04 16:57:01,623 INFO org.apache.flink.cdc.connectors.mysql.source.utils.RecordUtils - Checking if DDL might be an OSC renaming event... rename /* gh-ost */ table `dinky`.`dinky_user` to `dinky`.`_dinky_user_del`
2025-08-04 16:57:01,624 INFO org.apache.flink.cdc.connectors.mysql.source.utils.RecordUtils - Determined the shorter TableId dinky_user is the renaming source.
2025-08-04 16:57:01,624 INFO org.apache.flink.cdc.connectors.mysql.source.utils.RecordUtils - Determined the longer TableId _dinky_user_del is the renaming target.
2025-08-04 16:57:01,624 INFO org.apache.flink.cdc.connectors.mysql.source.utils.RecordUtils - Renamed to TableId name _dinky_user_del matches OSC temporary TableId pattern, yield dinky_user.
2025-08-04 16:57:01,624 INFO org.apache.flink.cdc.connectors.mysql.debezium.reader.BinlogSplitReader - Received the ending event of tableId:dinky._dinky_user_del,dinky_user,finishedTableId:dinky.dinky_user
2025-08-04 16:57:01,624 INFO org.apache.flink.cdc.connectors.mysql.debezium.reader.BinlogSplitReader - Received the ending event of table dinky.dinky_user. Emit corresponding DDL event now.
2025-08-04 16:57:01,624 INFO org.apache.flink.cdc.connectors.mysql.debezium.reader.BinlogSplitReader - remove pendingSchemaChangeEvents:dinky.dinky_user
2025-08-04 16:57:01,626 INFO org.apache.flink.cdc.connectors.mysql.source.utils.RecordUtils - Checking if DDL might be an OSC renaming event... rename /* gh-ost */ table `dinky`.`_dinky_user_gho` to `dinky`.`dinky_user`
2025-08-04 16:57:01,626 INFO org.apache.flink.cdc.connectors.mysql.source.utils.RecordUtils - Determined the shorter TableId dinky_user is the renaming source.
2025-08-04 16:57:01,626 INFO org.apache.flink.cdc.connectors.mysql.source.utils.RecordUtils - Determined the longer TableId _dinky_user_del is the renaming target.
2025-08-04 16:57:01,626 INFO org.apache.flink.cdc.connectors.mysql.source.utils.RecordUtils - Renamed to TableId name _dinky_user_del matches OSC temporary TableId pattern, yield dinky_user.
2025-08-04 16:57:01,626 INFO org.apache.flink.cdc.connectors.mysql.debezium.reader.BinlogSplitReader - Received the ending event of tableId:dinky._dinky_user_del,dinky_user,finishedTableId:dinky.dinky_user
2025-08-04 16:57:01,626 INFO org.apache.flink.cdc.connectors.mysql.debezium.reader.BinlogSplitReader - Received the ending event of table dinky.dinky_user. Emit corresponding DDL event now.
2025-08-04 16:57:01,626 ERROR org.apache.flink.cdc.connectors.mysql.debezium.reader.BinlogSplitReader - Error: met an unexpected osc finish event. Current pending events: {}, Record: DataChangeEvent [record=SourceRecord{sourcePartition={server=mysql_binlog_source}, sourceOffset={transaction_id=null, ts_sec=1754297821, file=mysql-bin.000003, pos=181321, server_id=1}} ConnectRecord{topic='mysql_binlog_source', kafkaPartition=0, key=Struct{databaseName=dinky}, value=Struct{source=Struct{version=1.9.8.Final,connector=mysql,name=mysql_binlog_source,ts_ms=1754297821468,db=dinky,table=_dinky_user_del,dinky_user,server_id=1,file=mysql-bin.000003,pos=181119,row=0},historyRecord={"source":{"file":"mysql-bin.000003","pos":181119,"server_id":1},"position
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Fix potential exception when online schema change happened.
Why did this happen?
Because when making table schema changes, the original table was not locked.
And the online schema change corresponds to a set of SQL statements, which were not processed completely before being issued. There may be a situation where the table structure does not correspond.