[Enhancement] Improve automatic DDL handling for full-database sync in CdcTools

[sgczy2746995629-blip]

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Description

📝 Description

When using CdcTools with the oracle-sync-database mode for full-database synchronization,
the automatic DDL handling is still not stable under the --schema-change-mode debezium_structure mode.
We are using this mode intentionally to support multiple heterogeneous data sources (Oracle, MySQL, PostgreSQL, etc.), since sql_parser mode is not fully compatible with all of them.
However, when schema changes (DDL) occur — especially frequent ALTER TABLE ADD/DROP COLUMN — Doris sometimes fails to synchronize the schema correctly.

⚙️ Current Behavior

• Some DDL operations (such as ADD COLUMN or DROP COLUMN) are not correctly applied to Doris tables.
• When multiple DDLs occur within a short period, Doris schema can go out of sync with the source.
• The connector logs occasionally show parsing or schema errors like:

  "The recordRoot cannot extract ddl sql"
"Column does not exist" when Doris attempts to drop an already-dropped column.

• These issues seem more frequent under debezium_structure mode.

✅ Expected Behavior

• DDL synchronization should be consistent and idempotent even when multiple DDLs occur rapidly.
• Doris should gracefully skip redundant DDLs (for example, when a column already exists or is already dropped).
• The debezium_structure mode should provide better schema evolution handling across multiple database dialects.
• Ideally, CdcTools could include retry or verification mechanisms to validate Doris schema alignment after each DDL event.

🧩 Environment

• Doris Flink Connector: 1.18-25.1.0
• Flink Version: 1.18.0
• Oracle Source: 19c (LogMiner)
• Schema Change Mode: debezium_structure
• Sync Mode: oracle-sync-database (CdcTools)
• Sink: Doris 2.x

🧾 Example Log

schema change status:true, ddl: ALTER TABLE test_db.EX_CTRL_CARE_PLAN DROP COLUMN PLAN_TYPE
schema change error : Failed to execute sql: Column does not exist: PLAN_TYPE
The recordRoot cannot extract ddl sql

Solution

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