edgarRd commented on a change in pull request #1499:
URL: https://github.com/apache/iceberg/pull/1499#discussion_r497051730
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File path: site/docs/spec.md
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@@ -416,25 +530,91 @@ Notes:
### Delete Formats
-This section details how to encode row-level deletes in Iceberg metadata.
Row-level deletes are not supported in the current format version 1. This part
of the spec is not yet complete and will be completed as format version 2.
+This section details how to encode row-level deletes in Iceberg delete files.
Row-level deletes are not supported in v1.
+
+Row-level delete files are valid Iceberg data files: files must use valid
Iceberg formats, schemas, and column projection. It is recommended that delete
files are written using the table's default file format.
+
+Row-level delete files are tracked by manifests, like data files. A separate
set of manifests is used for delete files, but the manifest schemas are
identical.
-#### Position-based Delete Files
+Both position and equality deletes allow encoding deleted row values with a
delete. This can be used to reconstruct a stream of changes to a table.
-Position-based delete files identify rows in one or more data files that have
been deleted.
+
+#### Position Delete Files
+
+Position-based delete files identify deleted rows by file and position in one
or more data files, and may optionally contain the deleted row.
+
+A data row is deleted if there is an entry in a position delete file for the
row's file and position in the data file, starting at 0.
Position-based delete files store `file_position_delete`, a struct with the
following fields:
-| Field id, name | Type | Description
|
-|-------------------------|---------------------------------|--------------------------------------------------------------------------------------------------------------------------|
-| **`1 file_path`** | `required string` | The full URI of a
data file with FS scheme. This must match the `file_path` of the target data
file in a manifest entry. |
-| **`2 position`** | `required long` | The ordinal
position of a deleted row in the target data file identified by `file_path`,
starting at `0`. |
+| Field id, name | Type | Description |
+|-----------------------------|------------------------|-------------|
+| **`2147483546 file_path`** | `string` | Full URI or a data
file with FS scheme. This must match the `file_path` of the target data file in
a manifest entry |
+| **`2147483545 pos`** | `long` | Ordinal position of a
deleted row in the target data file identified by `file_path`, starting at `0` |
+| **`2147483544 row`** | `required struct<...>` | Deleted row values.
Omit the column when not storing deleted rows. |
Review comment:
I think this is a bit confusing, it's a `required struct` that could be
omitted?
> Omit the column when not storing deleted rows.
Also a above it mentions:
> and may optionally contain the deleted row.
Is this column `required` or am I missing something?
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