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new 4ae5b30 Spec: Add file and position delete file (#887)
4ae5b30 is described below
commit 4ae5b30269e2638c0268722fe2e59d603517f0eb
Author: Chen, Junjie <[email protected]>
AuthorDate: Sat Apr 4 01:24:41 2020 +0800
Spec: Add file and position delete file (#887)
Co-authored-by: Ryan Blue <[email protected]>
---
site/docs/spec.md | 21 +++++++++++++++++++++
1 file changed, 21 insertions(+)
diff --git a/site/docs/spec.md b/site/docs/spec.md
index df1c0c4..921c100 100644
--- a/site/docs/spec.md
+++ b/site/docs/spec.md
@@ -333,6 +333,27 @@ Table metadata is stored as JSON. Each table metadata
change creates a new table
The atomic operation used to commit metadata depends on how tables are tracked
and is not standardized by this spec. See the sections below for examples.
+### Delete Format
+
+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.
+
+#### Position-based Delete Files
+
+Position-based delete files identify rows in one or more data files that have
been deleted.
+
+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`. |
+
+The rows in the delete file must be sorted by `file_path` then `position` to
optimize filtering rows while scanning.
+
+* Sorting by `file_path` allows filter pushdown by file in columnar storage
formats.
+* Sorting by `position` allows filtering rows while scanning, to avoid
keeping deletes in memory.
+
+Though the delete files can be written using any supported data file format in
Iceberg, it is recommended to write delete files with same file format as the
table's file format.
#### Commit Conflict Resolution and Retry
