Re: [I] Flink API rewriteDataFile How to set up scanning based on file size [iceberg]

["pvary (via GitHub)" <gi...@apache.org>]

pvary commented on issue #9386:
URL: https://github.com/apache/iceberg/issues/9386#issuecomment-1875644441

   If a file is bigger than the TARGET_FILE_SIZE, it will create multiple splits when we read it. The last split of the file is a good candidate to add to merge with a new split, so it could be reasonable to rewrite these files.
   
   For example, you have multiple files:
   - File1: 158M
   - File2: 158M
   
   If the files are not rewriten, the resulting scan will have 4 splits (File1(0-128M), File1(129-158M), File2(0-128M), File2(129-159M)). If the files are rewritten the resulting scan will have 3 splits (File1' (File1(0-128)), File2' (File2(0,138)) and File3' (File1(129-158M) + File2(129-158M)))
   
   Having 3 splits instead of 4 could have a serious performance impact.


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