oracledb_cdc: Update commit_ts_ms to use a more accurate commit time

[josephwoodward]

No description provided.

[claude]

After this change, the Timestamp field on MessageEvent is sourced from dml.CommitTimestamp, which is now the value of V$LOGMNR_CONTENTS.COMMIT_TIMESTAMP. That field is what drives the source_ts_ms metadata in batcher.go#L173-L178, but the documented contract for source_ts_ms in input_oracledb_cdc.go#L80-L82 explicitly states it reflects "the database server's wall-clock time at the moment the DML executed, not the transaction commit time." After this PR, source_ts_ms and commit_ts_ms will be identical (both the commit time), and source_ts_ms will no longer match its documented meaning. Consider keeping the per-row TIMESTAMP column selected alongside COMMIT_TIMESTAMP so the operation timestamp continues to populate source_ts_ms while only commit_ts_ms is corrected.

[claude]

Commits

1. Commit message oracledb_cdc: Update commit_ts_ms to use a more accurate commit time violates the message format: the message after system: must start lowercase (e.g., update, not Update).

Review
The change correctly switches commit_ts_ms to be sourced from V$LOGMNR_CONTENTS.COMMIT_TIMESTAMP, fixing the previous bug where commit_ts_ms was actually the operation timestamp. However, because the TIMESTAMP column was dropped from the query entirely, the MessageEvent.Timestamp field (which drives source_ts_ms) is now also set to the commit time, conflicting with the documented contract for source_ts_ms.

1. source_ts_ms will now report the transaction commit time, contradicting the documented behavior in input_oracledb_cdc.go#L80-L82. See inline comment.