shuwenwei opened a new pull request, #719:
URL: https://github.com/apache/tsfile/pull/719

   ## Background
   
   When rewriting a value chunk to a new data type, the rewrite logic relies on
   TableChunkReader to iterate over time-value pairs using the provided time
   chunk and value chunk.
   
   However, in the presence of time deletions, the original implementation
   passed the original timeChunk directly into TableChunkReader. Since the
   time chunk still contained deletion intervals, the filtered time sequence 
could
   become inconsistent with the value chunk being rewritten.
   
   ## Problem
   
   With time deletions applied, the rewritten value chunk could contain points
   that are not properly aligned with the corresponding timestamps in the time
   chunk. This results in:
   
   * Incorrect time-value pairing
   * Inconsistent rewritten chunks
   * Potential query correctness issues after type modification
   
   ## Solution
   
   This PR fixes the issue by reconstructing a clean time chunk before rewrite:
   
   * A new Chunk is created from the original time chunk’s header, data,
   statistics, and encryption parameters
   * Deletion intervals are intentionally removed from the time chunk used by
   TableChunkReader
   * The rewrite process now iterates over fully aligned time-value pairs
   
   This guarantees that the rewritten value chunk remains correctly aligned with
   the time chunk, even when time deletions exist.
   
   ## Impact
   
   * Ensures correctness when rewriting value chunks with a new data type
   * Fixes potential time-value misalignment caused by time deletions
   * No behavior change for cases without deletions


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