yguy-ryft commented on code in PR #13432:
URL: https://github.com/apache/iceberg/pull/13432#discussion_r2228731547
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docs/docs/maintenance.md:
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@@ -63,20 +63,16 @@ Expiring old snapshots removes them from metadata, so they
are no longer availab
### Remove old metadata files
-Iceberg keeps track of table metadata using JSON files. Each change to a table
produces a new metadata file to provide atomicity.
+Iceberg keeps track of table metadata using JSON files. Each change to a table
produces a new metadata file to provide atomicity. Old metadata files are kept
for history by default, and are tracked in the `metadata-log` field of the
metadata file. Tables with frequent commits, like those written by streaming
jobs, may need to regularly clean metadata files to reduce metadata overhead.
-Old metadata files are kept for history by default. Tables with frequent
commits, like those written by streaming jobs, may need to regularly clean
metadata files.
+The number of metadata files being **tracked** is defined by
`write.metadata.previous-versions-max` (default is 100).
-To automatically clean metadata files, set
`write.metadata.delete-after-commit.enabled=true` in table properties. This
will keep some metadata files (up to `write.metadata.previous-versions-max`)
and will delete the oldest metadata file after each new one is created.
+To automatically delete older metadata files when they become untracked, set
`write.metadata.delete-after-commit.enabled=true` in table properties. This
will keep some metadata files as tracked (up to
`write.metadata.previous-versions-max`), and will delete the oldest metadata
file every time a new one is created.
+Alternatively, untracked metadata files can be deleted as part of [orphan file
deletion](#delete-orphan-files).
-| Property | Description
|
-| --------------------------------------------
|--------------------------------------------------------------------------|
-| `write.metadata.delete-after-commit.enabled` | Whether to delete old
**tracked** metadata files after each table commit |
-| `write.metadata.previous-versions-max` | The number of old metadata
files to keep |
-
-Note that this will only delete metadata files that are **tracked** in the
metadata log and will not delete orphaned metadata files.
-Example: With `write.metadata.delete-after-commit.enabled=false` and
`write.metadata.previous-versions-max=10`, one will have 10 tracked metadata
files and 90 orphaned metadata files after 100 commits.
-Configuring `write.metadata.delete-after-commit.enabled=true` and
`write.metadata.previous-versions-max=20` will not automatically delete
metadata files. Tracked metadata files would be deleted again when reaching
`write.metadata.previous-versions-max=20`.
Review Comment:
@gaborkaszab this was just rephrased, so it'll be clear that there are two
bullets with two examples. Is there any information missing there in your
opinion?
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