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https://issues.apache.org/jira/browse/FLINK-39832?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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ASF GitHub Bot updated FLINK-39832:
-----------------------------------
Labels: pull-request-available (was: )
> [Bug] Oracle pipeline connector maps NUMBER(p,0) with p>=19 to BIGINT,
> causing primary key collision and row collapse in downstream sinks
> -------------------------------------------------------------------------------------------------------------------------------------------
>
> Key: FLINK-39832
> URL: https://issues.apache.org/jira/browse/FLINK-39832
> Project: Flink
> Issue Type: Bug
> Components: Flink CDC
> Affects Versions: 1.20.4
> Reporter: Zhouqing
> Priority: Major
> Labels: pull-request-available
>
> When an Oracle source table has a column defined as NUMBER(p, 0) with p >=
> 19 (e.g. NUMBER(19,0) as a primary key), the flink-cdc pipeline connector
> incorrectly maps it to BIGINT. However, Debezium internally encodes values
> with precision >= 19 as DECIMAL (variable-length BYTES). This mismatch causes
> the sink to read a BinaryRecordData pointer as a long value, producing a
> constant garbage PK (e.g. 171798691841 = 0x28_00000001) for every row. With
> upsert sinks, all rows collapse into one.
> Affected Version: 3.6.0 (both -1.20 and -2.2 variants)
> Root Cause
> Two code paths disagree on the type for NUMBER(p, 0) when p >= 19:
> - OracleTypeUtils.fromDbzColumn (builds CDC schema): maps NUMBER(p, 0) for
> any p to BIGINT
> - DebeziumSchemaDataTypeInference.inferBytes (runtime): maps NUMBER(p, 0)
> with p >= 19 to DECIMAL(p, 0)
> The CreateTableEvent declares the column as BIGINT, but BinaryRecordData
> stores the value in DECIMAL non-compact layout (8-byte pointer: length << 32
> | offset). When the sink calls getLong(idx), it reads the pointer — same
> value for every row — so PK-based upsert folds all rows into one.
> Reproduction
> 1. Create an Oracle table:
> CREATE TABLE FLINKUSER.FLINK_USER (
> ID NUMBER(19,0) PRIMARY KEY,
> NAME VARCHAR2(64),
> AGE NUMBER(10,0),
> GENDER VARCHAR2(2)
> );
> INSERT INTO FLINKUSER.FLINK_USER VALUES (1, 'zhangsan', 18, 'M');
> INSERT INTO FLINKUSER.FLINK_USER VALUES (2, 'lisi', 19, 'F');
> INSERT INTO FLINKUSER.FLINK_USER VALUES (3, 'wangwu', 20, 'M');
> COMMIT;
> 2. Run a flink-cdc pipeline with Oracle source and any upsert-capable sink
> (e.g. MaxCompute, Paimon).
> 3. Observe the sink table: only 1 row exists. All IDs became 171798691841.
> NUMBER(10,0) and NUMBER(18,0) work correctly. The bug is specific to p >=
> 19.
> Proposed Fix
> In OracleTypeUtils.fromDbzColumn, align with Debezium's boundary: return
> BIGINT only when precision is between 1 and 18; for p >= 19 (or unknown
> precision), return DECIMAL(p, 0).
> Test Results (with patch applied)
> - NUMBER(19,0) snapshot 3 rows (ID 1/2/3): Before = all IDs 171798691841, 1
> row; After = IDs correct, 3 rows
> - INSERT ID = 9000000000000000001: Before = also becomes 171798691841;
> After = preserved correctly
> - UPDATE / DELETE: Before = rows already collapsed, meaningless; After =
> works correctly
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