cloud-fan opened a new pull request #33002:
URL: https://github.com/apache/spark/pull/33002
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### What changes were proposed in this pull request?
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Currently, the batch and streaming file writers generate the file name a bit
differently:
1. The batch file writer, generates the file name with partition ID and job
id (which is a unique UUID)
2. The streaming file writer, generates the file name with partition ID and
a fresh UUID
The reason for it is:
1. The file output committer for batch creates a unique staging directory
for each task attempt, so partition ID is good enough to avoid file name
collision, as concurrent task attempts (task retry, speculative tasks) are well
handled by the staging directory.
2. The file output committe for streaming does not use staging directories.
It writes files to the final path directly and uses a manifest file to track
the committed files. Thus, partition ID is not sufficient to avoid file name
collision. That's why we add a fresh UUID to the file name.
This PR proposes to unify the file name, by putting task attempt ID (which
must be unique within the job) and the job ID in the file name.
### Why are the changes needed?
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Remove confusion when people try to understand how Spark generates file
names. We can further refactor the code later to move the file name generation
outside of the output committer.
### Does this PR introduce _any_ user-facing change?
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No. The read side doesn't care about file name at all, and only care about
how to list files. No backward compatibility issues.
### How was this patch tested?
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existing tests
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