amogh-jahagirdar commented on code in PR #16025:
URL: https://github.com/apache/iceberg/pull/16025#discussion_r4118312107
##########
format/spec.md:
##########
@@ -742,18 +758,126 @@ The `data_file` struct consists of the following fields:
| | | _optional_ | **`144 content_offset`**
| `long` |
The offset in the file where the content starts [5] |
| | | _optional_ | **`145 content_size_in_bytes`**
| `long` |
The length of a referenced content stored in the file; required if
`content_offset` is present [5] |
-The `partition` struct stores the tuple of partition values for each file. Its
type is derived from the partition fields of the partition spec used to write
the manifest file. In v2, the partition struct's field ids must match the ids
from the partition spec.
+ The `partition` struct stores the tuple of partition values for each file.
Its type is derived from the partition fields of the partition spec used to
write the manifest file. In v2, the partition struct's field ids must match the
ids from the partition spec.
-The v4 `content_stats` container struct stores field-level metrics. Unlike the
metrics maps, the type of `content_stats` is based on table metadata, like
schema. Similar to the `partition` struct, the same type is used for all files
tracked in a manifest.
+ Notes:
+
+ 1. Single-value serialization for lower and upper bounds is detailed in
Appendix D.
+ 2. For `float` and `double`, the value `-0.0` must precede `+0.0`, as in
the IEEE 754 `totalOrder` predicate. NaNs are not permitted as lower or upper
bounds.
+ 3. If sort order ID is missing or unknown, then the order is assumed to be
unsorted. Only data files and equality delete files should be written with a
non-null order id. [Position deletes](#position-delete-files) are required to
be sorted by file and position, not a table order, and should set sort order id
to null. Readers must ignore sort order id for position delete files.
+ 4. Position delete metadata can use `referenced_data_file` when all
deletes tracked by the entry are in a single data file. Setting the referenced
file is required for deletion vectors.
+ 5. The `content_offset` and `content_size_in_bytes` fields are used to
reference a specific blob for direct access to a deletion vector. For deletion
vectors, these values are required and must exactly match the `offset` and
`length` stored in the Puffin footer for the deletion vector blob.
+ 6. The following field ids are reserved on `data_file`: 141.
+
+=== "v4"
+ **Tracked Files**
+
+ | Field id | Name | Type | Required | Description |
+ |----------|------|------|----------|-------------|
+ | 134 | **`content_type`** | `int` (0: DATA, 3: DATA_MANIFEST, 4:
DELETE_MANIFEST) | *required* | Type of content stored in the entry. |
+ | 157 | **`format_version`** | `int` (0: PRE-V4, 4: V4) | *required* |
Writer format version. |
+ | 100 | **`location`** | `string` | *required* | Location of the file or
manifest. |
+ | 101 | **`file_format`** | `string` | *required* | String file format
name: `avro`, `orc`, `parquet`, or `puffin` |
+ | 147 | **`tracking`** | `tracking` struct | *required* | Groups status,
snapshot, and sequence number. See tracking struct below. |
+ | 141 | **`spec_id`** | `int` | *optional* | ID of the partition spec used
to write this manifest or data file. |
+ | 140 | **`sort_order_id`** | `int` | *optional* | ID representing sort
order for this file. If missing or unknown, the order is assumed to be
unsorted. |
+ | 103 | **`record_count`** | `long` | *required* | Number of records in
this file. |
+ | 104 | **`file_size_in_bytes`** | `long` | *required* | Total file size
in bytes. |
+ | 146 | **`content_stats`** | `content_stats` struct | *optional* | Column
stats. See [Content Stats](#content-stats). |
+ | 150 | **`manifest_info`** | `manifest_info` struct | *optional* | See
manifest_info struct below. |
+ | 131 | **`key_metadata`** | `binary` | *optional* |
Implementation-specific key metadata for encryption. |
+ | 132 | **`split_offsets`** | `list<133: long>` | *optional* | Split
offsets for the data file. Must be sorted ascending. |
+ | 148 | **`deletion_vector`** | `deletion_vector` struct | *optional* |
Row-level deletion vector for a data file. |
+ | 158 | **`column_files`** | `list<159: column_file>` | *optional* |
Column update files associated with this entry. |
Review Comment:
Updated to "Column files associated with this file."
##########
format/spec.md:
##########
@@ -691,21 +707,118 @@ The `manifest_entry` struct consists of the following
fields:
| | _optional_ | **`4 file_sequence_number`** | `long`
| File sequence number indicating
when the file was added. Inherited when null and status is 1 (added). |
| _required_ | _required_ | **`2 data_file`** | `data_file`
`struct` (see below) | File path, partition tuple,
metrics, ... |
-The manifest entry fields are used to keep track of the snapshot in which
files were added or logically deleted. The `data_file` struct, defined below,
is nested inside the manifest entry so that it can be easily passed to job
planning without the manifest entry fields.
+ The manifest entry fields are used to keep track of the snapshot in which
files were added or logically deleted. The `data_file` struct, defined below,
is nested inside the manifest entry so that it can be easily passed to job
planning without the manifest entry fields.
-When a file is added to the dataset, its manifest entry should store the
snapshot ID in which the file was added and set status to 1 (added).
+ When a file is added to the dataset, its manifest entry should store the
snapshot ID in which the file was added and set status to 1 (added).
-When a file is replaced or deleted from the dataset, its manifest entry fields
store the snapshot ID in which the file was deleted and status 2 (deleted). The
file may be deleted from the file system when the snapshot in which it was
deleted is garbage collected, assuming that older snapshots have also been
garbage collected [1].
+ When a file is replaced or deleted from the dataset, its manifest entry
fields store the snapshot ID in which the file was deleted and status 2
(deleted). The file may be deleted from the file system when the snapshot in
which it was deleted is garbage collected, assuming that older snapshots have
also been garbage collected [1].
-Iceberg v2 adds data and file sequence numbers to the entry and makes the
snapshot ID optional. Values for these fields are inherited from manifest
metadata when `null`. That is, if the field is `null` for an entry, then the
entry must inherit its value from the manifest file's metadata, stored in the
manifest list.
-The `sequence_number` field represents the data sequence number and must never
change after a file is added to the dataset. The data sequence number
represents a relative age of the file content and should be used for planning
which delete files apply to a data file.
-The `file_sequence_number` field represents the sequence number of the
snapshot that added the file and must also remain unchanged upon assigning at
commit. The file sequence number can't be used for pruning delete files as the
data within the file may have an older data sequence number.
-The data and file sequence numbers are inherited only if the entry status is 1
(added). If the entry status is 0 (existing) or 2 (deleted), the entry must
include both sequence numbers explicitly.
+ Iceberg v2 adds data and file sequence numbers to the entry and makes the
snapshot ID optional. Values for these fields are inherited from manifest
metadata when `null`. That is, if the field is `null` for an entry, then the
entry must inherit its value from the manifest file's metadata, stored in the
manifest list.
+ The `sequence_number` field represents the data sequence number and must
never change after a file is added to the dataset. The data sequence number
represents a relative age of the file content and should be used for planning
which delete files apply to a data file.
+ The `file_sequence_number` field represents the sequence number of the
snapshot that added the file and must also remain unchanged upon assigning at
commit. The file sequence number can't be used for pruning delete files as the
data within the file may have an older data sequence number.
+ The data and file sequence numbers are inherited only if the entry status
is 1 (added). If the entry status is 0 (existing) or 2 (deleted), the entry
must include both sequence numbers explicitly.
-Notes:
+ Notes:
-1. Technically, data files can be deleted when the last snapshot that contains
the file as “live” data is garbage collected. But this is harder to detect and
requires finding the diff of multiple snapshots. It is easier to track what
files are deleted in a snapshot and delete them when that snapshot expires. It
is not recommended to add a deleted file back to a table. Adding a deleted file
can lead to edge cases where incremental deletes can break table snapshots.
-2. Manifest list files are required in v2, so that the `sequence_number` and
`snapshot_id` to inherit are always available.
+ 1. Technically, data files can be deleted when the last snapshot that
contains the file as "live" data is garbage collected. But this is harder to
detect and requires finding the diff of multiple snapshots. It is easier to
track what files are deleted in a snapshot and delete them when that snapshot
expires. It is not recommended to add a deleted file back to a table. Adding a
deleted file can lead to edge cases where incremental deletes can break table
snapshots.
+ 2. Manifest list files are required in v2, so that the `sequence_number`
and `snapshot_id` to inherit are always available.
+
+=== "v4"
+ **Content Entries**
+
+ | Field id | Name | Type | Write | Read | Description |
+ |----------|------|------|-------|------|-------------|
+ | 134 | **`content_type`** | `int` (0: DATA, 2: EQUALITY DELETES, 3:
DATA_MANIFEST, 4: DELETE_MANIFEST) | *required* | *required* | Type of content
stored in the entry. Content types 3 and 4 are only valid in root manifests. |
+ | 157 | **`format_version`** | `int` (0: PRE-V4, 4: V4) | *required* |
*required* | Writer format version. V4 writers must produce `format_version` 4.
|
+ | 100 | **`location`** | `string` | *required* | *required* | Location of
the file or manifest. |
+ | 101 | **`file_format`** | `string` | *required* | *required* | String
file format name: `avro`, `orc`, `parquet`, or `puffin` |
+ | 147 | **`tracking`** | `tracking` struct | *required* | *required* |
Groups status, snapshot, and sequence number. See tracking struct below. |
+ | 141 | **`spec_id`** | `int` | *optional* | *optional* | ID of the
partition spec used to write this manifest or data file. |
+ | 140 | **`sort_order_id`** | `int` | *optional* | *optional* | ID
representing sort order for this file. |
+ | 103 | **`record_count`** | `long` | *required* | *required* | Number of
records in this file. |
+ | 104 | **`file_size_in_bytes`** | `long` | *required* | *required* |
Total file size in bytes. |
+ | 146 | **`content_stats`** | `content_stats` struct | *optional* |
*optional* | Column stats. See [Column Stats
Improvements](#column-stats-improvements). |
+ | 150 | **`manifest_info`** | `manifest_info` struct | *optional* |
*optional* | See manifest_info struct below. |
+ | 131 | **`key_metadata`** | `binary` | *optional* | *optional* |
Implementation-specific key metadata for encryption. |
+ | 132 | **`split_offsets`** | `list<133: long>` | *optional* | *optional*
| Split offsets for the data or equality delete file. Must be sorted ascending.
|
+ | 135 | **`equality_ids`** | `list<136: int>` | *optional* | *optional* |
Field ids for row equality in equality delete files. |
+ | 148 | **`deletion_vector`** | `deletion_vector` struct | *optional* |
*optional* | Row-level deletion vector for a data file. |
+ | 158 | **`column_files`** | `list<159: column_file>` | *optional* |
*optional* | Column update files associated with this entry. |
+
+ Value 1 (POSITION_DELETES) is not used in v4. Writers must not produce
`content_type` 1.
+
+ V4 leaf data manifests must only contain entries with `content_type` 0
(DATA); V4 leaf delete manifests must only contain entries with `content_type`
2 (EQUALITY DELETES). A root manifest may reference V1-V3 manifests; V1-V3 leaf
manifest references must have `format_version` set to 0.
+
+ The following constraints apply based on `content_type`:
+
+ - `manifest_info` must be set when `content_type` is 3 or 4; must be null
otherwise.
+ - `deletion_vector` may only be set when `content_type` is 0; must be null
otherwise.
+ - `equality_ids` must be set when `content_type` is 2; must be null
otherwise.
+ - `column_files` must be null when `content_type` is not 0 or 3.
+ - `sort_order_id` must be null when `content_type` is 3 or 4 (manifests).
+ - `split_offsets` must be null when `content_type` is 3 or 4 (manifests).
+ - `tracking.deleted_positions` and `tracking.replaced_positions` must be
null when `content_type` is not 3 or 4.
+
+ **`tracking` struct (field 147)**
+
+ | Field id | Name | Type | Write | Read | Description |
+ |----------|------|------|-------|------|-------------|
+ | 0 | **`status`** | `int` (0: EXISTING, 1: ADDED, 2: DELETED, 3:
REPLACED, 4: MODIFIED) | *required* | *required* | Used to track additions,
deletions, replacements, and modifications. When a data file's
`deletion_vector` or `column_files` change, REPLACED marks the prior version of
the entry and MODIFIED marks the new, live version. For leaf manifest entries,
MODIFIED marks a live manifest whose `dv` changed. Deletes are not used in
scans. |
+ | 1 | **`snapshot_id`** | `long` | *optional* | *optional* | Snapshot ID
where the file was added or deleted. Inherited when null. Optional for leaf
manifests, required for root. |
+ | 5 | **`dv_snapshot_id`** | `long` | *optional* | *optional* | Snapshot
ID where the deletion vector was added. Inherited when null. Must be null when
`deletion_vector` is null. |
+ | 3 | **`sequence_number`** | `long` | *optional* | *optional* | Data
sequence number of the file. Inherited when null and status is 1 (ADDED). Must
equal `file_sequence_number` if `content_type` is 3 or 4. Optional for leaf
manifests, required for root. |
+ | 4 | **`file_sequence_number`** | `long` | *optional* | *optional* | File
sequence number indicating when the file was added. Inherited when null and
status is ADDED. Must equal `sequence_number` if `content_type` is 3 or 4. |
+ | 142 | **`first_row_id`** | `long` | *optional* | *optional* | The
`_row_id` for the first row in the data file if `content_type` is 0. If
`content_type` is 3, this is the starting `_row_id` to assign to rows added by
ADDED data files. See [First Row ID Inheritance](#first-row-id-inheritance). |
+ | 6 | **`deleted_positions`** | `binary` | *optional* | *optional* |
[TODO: link to roaring bitmap spec] Roaring bitmap of positions in the
referenced leaf manifest that were deleted in this snapshot. |
+ | 7 | **`replaced_positions`** | `binary` | *optional* | *optional* |
[TODO: link to roaring bitmap spec] Roaring bitmap of positions in the
referenced leaf manifest that were replaced in this snapshot. |
+
+ **`deletion_vector` struct (field 148)**
+
+ | Field id | Name | Type | Write | Read | Description |
+ |----------|------|------|-------|------|-------------|
+ | 155 | **`location`** | `string` | *required* | *required* | Location of
the Puffin file. |
+ | 144 | **`offset`** | `long` | *required* | *required* | Offset in the
file where the content starts. |
+ | 145 | **`size_in_bytes`** | `long` | *required* | *required* | Length of
the referenced content stored in the file. |
+ | 156 | **`cardinality`** | `long` | *required* | *required* | Cardinality
of the deletion vector. |
+ | 149 | **`key_metadata`** | `binary` | *optional* | *optional* |
Implementation-specific key metadata for encryption. |
+
+ **`manifest_info` struct (field 150)**
+
+ | Field id | Name | Type | Write | Read | Description |
+ |----------|------|------|-------|------|-------------|
+ | 504 | **`added_files_count`** | `long` | *required* | *required* | Count
of entries with status ADDED in the manifest. |
+ | 505 | **`existing_files_count`** | `long` | *required* | *required* |
Count of entries with status EXISTING in the manifest. |
+ | 506 | **`deleted_files_count`** | `long` | *required* | *required* |
Count of entries with status DELETED in the manifest. |
+ | 520 | **`replaced_files_count`** | `long` | *required* | *required* |
Count of entries with status REPLACED in the manifest. |
+ | 524 | **`modified_files_count`** | `long` | *required* | *required* |
Count of entries with status MODIFIED in the manifest. |
+ | 512 | **`added_rows_count`** | `long` | *required* | *required* | Total
number of rows in ADDED entries. |
+ | 513 | **`existing_rows_count`** | `long` | *required* | *required* |
Total number of rows in EXISTING entries. |
+ | 514 | **`deleted_rows_count`** | `long` | *required* | *required* |
Total number of rows in DELETED entries. |
+ | 521 | **`replaced_rows_count`** | `long` | *required* | *required* |
Total number of rows in REPLACED entries. |
+ | 525 | **`modified_rows_count`** | `long` | *required* | *required* |
Total number of rows in MODIFIED entries. |
+ | 516 | **`min_sequence_number`** | `long` | *required* | *required* |
Minimum data sequence number of all live entries in the manifest. |
+ | 522 | **`dv`** | `binary` | *optional* | *optional* | Roaring bitmap of
entry positions in the manifest that are not live in the current snapshot. |
+ | 523 | **`dv_cardinality`** | `long` | *optional* | *optional* |
Cardinality of the manifest deletion vector. Must be set when `dv` is non-null;
must be null otherwise. |
+
+ **`column_file` struct (element 159 of `column_files`, field 158)**
Review Comment:
Yes, it's intentional. The struct is part of this PR, and the column update
write rules and constraints should be done separately.
##########
format/spec.md:
##########
@@ -820,14 +944,18 @@ Each stats struct holds statistics for one table field.
It may contain the follo
| Requirement | Offset | Name | Type
| Included for | Description |
|-------------|--------|---------------------------|---------------------------|-----------------------------------------------|-------------|
-| _optional_ | 1 | `lower_bound` | Field type or `geo_lower`
| all primitives or `variant` | Lower bound stored as the
field's type, or `geo_lower` for geo types |
-| _optional_ | 2 | `upper_bound` | Field type or `geo_upper`
| all primitives or `variant` | Upper bound stored as the
field's type, or `geo_upper` for geo types |
+| _optional_ | 1 | `lower_bound` | Field type or `geo_lower`
| all primitives or `variant` | Lower bound stored as the
field's type, or `geo_lower` for geo types [1] |
Review Comment:
Yeah it's the float/double note. Moved the `[1]` next to "the field's type"
so it doesn't read like it's about geo types.
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