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https://issues.apache.org/jira/browse/FLINK-40201?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=18097871#comment-18097871
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Mohammad Suhel Ksolves commented on FLINK-40201:
------------------------------------------------
A pull request has been opened for this issue:
https://github.com/apache/flink-cdc/pull/4481
The PR targets release-3.6 and includes 1 commit covering all 7 fixes described
above.
> [Oracle CDC] Fix compatibility with Oracle 26ai and Debezium 3.4.2.Final
> ------------------------------------------------------------------------
>
> Key: FLINK-40201
> URL: https://issues.apache.org/jira/browse/FLINK-40201
> Project: Flink
> Issue Type: Bug
> Components: Flink CDC
> Affects Versions: cdc-3.6.0
> Reporter: Mohammad Suhel Ksolves
> Priority: Major
> Labels: pull-request-available
>
> h2. Background
> Flink CDC 3.6's Oracle connector vendors several Debezium internal classes
> that were written against an older Debezium API. Oracle 26ai (23.26.x)
> requires features only available in Debezium 3.4.2.Final (specifically
> UnbufferedLogMinerStreamingChangeEventSource introduced in Debezium 2.x).
> When Debezium 3.4.2.Final is used, the vendored classes produce runtime
> errors because they still carry old API signatures. Simply swapping the
> Debezium JAR is not sufficient — several source-level fixes are required to
> align the vendored classes with the Debezium 3.4.2 API.
> h2. Problem
> Oracle CDC connector in Flink CDC 3.6 fails with Oracle 26ai (CDB/PDB mode)
> when using Debezium 3.4.2.Final. Multiple runtime errors prevent snapshot and
> streaming CDC from working end-to-end:
> # {*}NoSuchMethodError on LogMinerChangeRecordEmitter{*}: The vendored
> LogMinerChangeRecordEmitter carries a 10-arg constructor (from an older
> Debezium API) but Debezium 3.4.2's
> UnbufferedLogMinerStreamingChangeEventSource calls a 9-arg constructor (rowId
> parameter was removed in Debezium 2.x).
> # {*}NullPointerException in ResumePositionProvider.close(){*}: The close()
> method calls sessionContext.close() without null-guarding sessionContext. If
> lazy initialisation fails after connection is assigned but before
> sessionContext is assigned, close() produces a secondary NPE that hides the
> root cause exception.
> # {*}Invalid JDBC connection string in ResumePositionProvider{*}: When the
> connector config carries "database.*" prefixed keys, OracleConnection
> receives keys like "database.hostname" instead of "hostname", producing a
> malformed JDBC URL and connection failure.
> # {*}ORA-01031 on row count query{*}: OracleUtils.queryApproximateRowCnt()
> used ANALYZE TABLE which requires the ANALYZE ANY system privilege. Standard
> CDC users do not have this privilege. Fixed by querying ALL_TABLES.NUM_ROWS
> instead.
> # {*}ORA-00942 / schema recovery failure{*}: readSchemaForCapturedTables()
> fails in CDB/PDB mode because Oracle JDBC returns the PDB name as TABLE_CAT
> in JDBC metadata results, but the TableId has a null catalog. Fixed by using
> a catalog-agnostic filter when calling readSchema().
> # {*}NullPointerException on absent ROWID Connect header{*}: Debezium 3.4.2
> removed the getEmitConnectHeaders() override that injected a ROWID into Kafka
> Connect headers. OracleSourceFetchTaskContext.isRecordBetween() then crashes
> on tables without a primary key because headers.iterator().next() throws
> NoSuchElementException when no header is present.
> # {*}ClassNotFoundException at runtime{*}: debezium-common classes (e.g.
> RelationalDatabaseSchema) are referenced at runtime but were not included in
> the Maven shade assembly, causing ClassNotFoundException when the fat JAR is
> used.
> h2. Steps to Reproduce
> # Set up Oracle 26ai in CDB/PDB mode (e.g. FREE CDB + FREEPDB1)
> # Upgrade Debezium version in pom.xml to 3.4.2.Final
> # Run Oracle CDC connector with scan.startup.mode=initial
> # Observe failures listed above during snapshot and streaming phases
> h2. Fix
> * Update vendored LogMinerChangeRecordEmitter to 9-arg constructor matching
> Debezium 3.4.2
> * Add local ResumePositionProvider override: null-guard on sessionContext in
> close() and catch block; strip "database." prefix from JdbcConfiguration
> before creating OracleConnection
> * Fix OracleUtils.queryApproximateRowCnt() to use ALL_TABLES.NUM_ROWS
> instead of ANALYZE TABLE
> * Fix OracleSchema.getTableSchema() to use a catalog-agnostic TableFilter
> for readSchema() so it works correctly in Oracle CDB/PDB mode
> * Guard isRecordBetween() against absent ROWID Connect header; fall back to
> SCN-range inclusion for tables without a primary key (multi-chunk PK-less
> tables should set scan.incremental.snapshot.chunk.key-column explicitly)
> * Include debezium-common in Maven shade assembly to prevent
> ClassNotFoundException at runtime
> * Add EmbeddedFlinkSchemaHistory and RelationalDatabaseSchema adapters for
> Debezium 3.x API
> h2. Verification
> Tested end-to-end pipeline: Oracle 26ai FREE (CDB/FREEPDB1) → Flink CDC
> 3.6-SNAPSHOT → StarRocks sink. Confirmed 3 snapshot rows and a live CDC
> UPDATE propagated correctly using Debezium 3.4.2.Final and
> scan.startup.mode=initial.
> h2. Environment
> * Flink CDC: 3.6-SNAPSHOT
> * Debezium: 3.4.2.Final
> * Oracle: 26ai (FREE edition, CDB + FREEPDB1 PDB)
> * Java: 17
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