stevenzwu commented on code in PR #14656:
URL: https://github.com/apache/iceberg/pull/14656#discussion_r3197132965
##########
format/spec.md:
##########
@@ -790,33 +793,34 @@ A manifest list is a valid Iceberg data file: files must
use valid Iceberg forma
Manifest list files store `manifest_file`, a struct with the following fields:
-| v1 | v2 | v3 | Field id, name |
Type | Description
|
-| ---------- | ----------
|------------|----------------------------------|---------------------------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------|
-| _required_ | _required_ | _required_ | **`500 manifest_path`** |
`string` | Location of the manifest file
|
-| _required_ | _required_ | _required_ | **`501 manifest_length`** |
`long` | Length of the manifest file in
bytes
|
-| _required_ | _required_ | _required_ | **`502 partition_spec_id`** |
`int` | ID of a partition spec used to
write the manifest; must be listed in table metadata `partition-specs`
|
-| | _required_ | _required_ | **`517 content`** |
`int` with meaning: `0: data`, `1: deletes` | The type of files tracked by the
manifest, either data or delete files; 0 for all v1 manifests
|
-| | _required_ | _required_ | **`515 sequence_number`** |
`long` | The sequence number when the
manifest was added to the table; use 0 when reading v1 manifest lists
|
-| | _required_ | _required_ | **`516 min_sequence_number`** |
`long` | The minimum data sequence number
of all live data or delete files in the manifest; use 0 when reading v1
manifest lists |
-| _required_ | _required_ | _required_ | **`503 added_snapshot_id`** |
`long` | ID of the snapshot where the
manifest file was added
|
-| _optional_ | _required_ | _required_ | **`504 added_files_count`** |
`int` | Number of entries in the manifest
that have status `ADDED` (1), when `null` this is assumed to be non-zero
|
-| _optional_ | _required_ | _required_ | **`505 existing_files_count`** |
`int` | Number of entries in the manifest
that have status `EXISTING` (0), when `null` this is assumed to be non-zero
|
-| _optional_ | _required_ | _required_ | **`506 deleted_files_count`** |
`int` | Number of entries in the manifest
that have status `DELETED` (2), when `null` this is assumed to be non-zero
|
-| _optional_ | _required_ | _required_ | **`512 added_rows_count`** |
`long` | Number of rows in all of files in
the manifest that have status `ADDED`, when `null` this is assumed to be
non-zero |
-| _optional_ | _required_ | _required_ | **`513 existing_rows_count`** |
`long` | Number of rows in all of files in
the manifest that have status `EXISTING`, when `null` this is assumed to be
non-zero |
-| _optional_ | _required_ | _required_ | **`514 deleted_rows_count`** |
`long` | Number of rows in all of files in
the manifest that have status `DELETED`, when `null` this is assumed to be
non-zero |
-| _optional_ | _optional_ | _optional_ | **`507 partitions`** |
`list<508: field_summary>` (see below) | A list of field summaries for
each partition field in the spec. Each field in the list corresponds to a field
in the manifest file’s partition spec. |
-| _optional_ | _optional_ | _optional_ | **`519 key_metadata`** |
`binary` | Implementation-specific key
metadata for encryption
|
-| | | _optional_ | **`520 first_row_id`** |
`long` | The starting `_row_id` to assign
to rows added by `ADDED` data files [First Row ID
Assignment](#first-row-id-assignment) |
+=== "v1 - v3"
+ | v1 | v2 | v3 | Field id, name
| Type | Description |
+ | ---------- | ----------
|------------|-------------------------------------|---------------------------------------------|-------------|
+ | _required_ | _required_ | _required_ | **`500 manifest_path`**
| `string` | Location of the manifest file
|
+ | _required_ | _required_ | _required_ | **`501 manifest_length`**
| `long` | Length of the manifest file
in bytes |
+ | _required_ | _required_ | _required_ | **`502 partition_spec_id`**
| `int` | ID of a partition spec used
to write the manifest; must be listed in table metadata `partition-specs` |
+ | | _required_ | _required_ | **`517 content`**
| `int` with meaning: `0: data`, `1: deletes` | The type of files tracked by
the manifest, either data or delete files; 0 for all v1 manifests |
+ | | _required_ | _required_ | **`515 sequence_number`**
| `long` | The sequence number when the
manifest was added to the table; use 0 when reading v1 manifest lists |
+ | | _required_ | _required_ | **`516 min_sequence_number`**
| `long` | The minimum data sequence
number of all live data or delete files in the manifest; use 0 when reading v1
manifest lists |
+ | _required_ | _required_ | _required_ | **`503 added_snapshot_id`**
| `long` | ID of the snapshot where the
manifest file was added |
+ | _optional_ | _required_ | _required_ | **`504 added_files_count`**
| `int` | Number of entries in the
manifest that have status `ADDED` (1), when `null` this is assumed to be
non-zero |
+ | _optional_ | _required_ | _required_ | **`505 existing_files_count`**
| `int` | Number of entries in the
manifest that have status `EXISTING` (0), when `null` this is assumed to be
non-zero |
+ | _optional_ | _required_ | _required_ | **`506 deleted_files_count`**
| `int` | Number of entries in the
manifest that have status `DELETED` (2), when `null` this is assumed to be
non-zero |
+ | _optional_ | _required_ | _required_ | **`512 added_rows_count`**
| `long` | Number of rows in all of
files in the manifest that have status `ADDED`, when `null` this is assumed to
be non-zero |
+ | _optional_ | _required_ | _required_ | **`513 existing_rows_count`**
| `long` | Number of rows in all of
files in the manifest that have status `EXISTING`, when `null` this is assumed
to be non-zero |
+ | _optional_ | _required_ | _required_ | **`514 deleted_rows_count`**
| `long` | Number of rows in all of
files in the manifest that have status `DELETED`, when `null` this is assumed
to be non-zero |
+ | _optional_ | _optional_ | _optional_ | **`507 partitions`**
| `list<508: field_summary>` | A list of field summaries for
each partition field in the spec. Each field in the list corresponds to a field
in the manifest file’s partition spec. |
Review Comment:
Content drop: original Type column was `list<508: field_summary>` **(see
below)** — the `(see below)` cross-reference to the field_summary table that
follows on line 818 was removed. Restoring it preserves discoverability.
##########
format/spec.md:
##########
@@ -921,33 +926,34 @@ The atomic operation used to commit metadata depends on
how tables are tracked a
Table metadata consists of the following fields:
-| v1 | v2 | v3 | Field |
Description
|
-| ---------- | ----------
|------------|-----------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
-| _required_ | _required_ | _required_ | **`format-version`** | An
integer version number for the format. Implementations must throw an exception
if a table's version is higher than the supported version.
|
-| _optional_ | _required_ | _required_ | **`table-uuid`** | A UUID
that identifies the table, generated when the table is created. Implementations
must throw an exception if a table's UUID does not match the expected UUID
after refreshing metadata.
|
-| _required_ | _required_ | _required_ | **`location`** | The
table's base location. This is used by writers to determine where to store data
files, manifest files, and table metadata files.
|
-| | _required_ | _required_ | **`last-sequence-number`** | The
table's highest assigned sequence number, a monotonically increasing long that
tracks the order of snapshots in a table.
|
-| _required_ | _required_ | _required_ | **`last-updated-ms`** |
Timestamp in milliseconds from the unix epoch when the table was last updated.
Each table metadata file should update this field just before writing.
|
-| _required_ | _required_ | _required_ | **`last-column-id`** | An
integer; the highest assigned column ID for the table. This is used to ensure
columns are always assigned an unused ID when evolving schemas.
|
-| _required_ | | | **`schema`** | The
table’s current schema. (**Deprecated**: use `schemas` and `current-schema-id`
instead)
|
-| _optional_ | _required_ | _required_ | **`schemas`** | A list
of schemas, stored as objects with `schema-id`.
|
-| _optional_ | _required_ | _required_ | **`current-schema-id`** | ID of
the table's current schema.
|
-| _required_ | | | **`partition-spec`** | The
table’s current partition spec, stored as only fields. Note that this is used
by writers to partition data, but is not used when reading because reads use
the specs stored in manifest files. (**Deprecated**: use `partition-specs` and
`default-spec-id` instead)
|
-| _optional_ | _required_ | _required_ | **`partition-specs`** | A list
of partition specs, stored as full partition spec objects.
|
-| _optional_ | _required_ | _required_ | **`default-spec-id`** | ID of
the "current" spec that writers should use by default.
|
-| _optional_ | _required_ | _required_ | **`last-partition-id`** | An
integer; the highest assigned partition field ID across all partition specs for
the table. This is used to ensure partition fields are always assigned an
unused ID when evolving specs.
|
-| _optional_ | _optional_ | _optional_ | **`properties`** | A
string to string map of table properties. This is used to control settings that
affect reading and writing and is not intended to be used for arbitrary
metadata. For example, `commit.retry.num-retries` is used to control the number
of commit retries.
|
-| _optional_ | _optional_ | _optional_ | **`current-snapshot-id`** | `long`
ID of the current table snapshot; must be the same as the current ID of the
`main` branch in `refs`.
|
-| _optional_ | _optional_ | _optional_ | **`snapshots`** | A list
of valid snapshots. Valid snapshots are snapshots for which all data files
exist in the file system. A data file must not be deleted from the file system
until the last snapshot in which it was listed is garbage collected.
|
-| _optional_ | _optional_ | _optional_ | **`snapshot-log`** | A list
(optional) of timestamp and snapshot ID pairs that encodes changes to the
current snapshot for the table. Each time the current-snapshot-id is changed, a
new entry should be added with the last-updated-ms and the new
current-snapshot-id. When snapshots are expired from the list of valid
snapshots, all entries before a snapshot that has expired should be removed.
|
-| _optional_ | _optional_ | _optional_ | **`metadata-log`** | A list
(optional) of timestamp and metadata file location pairs that encodes changes
to the previous metadata files for the table. Each time a new metadata file is
created, a new entry of the previous metadata file location should be added to
the list. Tables can be configured to remove oldest metadata log entries and
keep a fixed-size log of the most recent entries after a commit. |
-| _optional_ | _required_ | _required_ | **`sort-orders`** | A list
of sort orders, stored as full sort order objects.
|
-| _optional_ | _required_ | _required_ | **`default-sort-order-id`** | Default
sort order id of the table. Note that this could be used by writers, but is not
used when reading because reads use the specs stored in manifest files.
|
-| | _optional_ | _optional_ | **`refs`** | A map
of snapshot references. The map keys are the unique snapshot reference names in
the table, and the map values are snapshot reference objects. There is always a
`main` branch reference pointing to the `current-snapshot-id` even if the
`refs` map is null.
|
-| _optional_ | _optional_ | _optional_ | **`statistics`** | A list
(optional) of [table statistics](#table-statistics).
|
-| _optional_ | _optional_ | _optional_ | **`partition-statistics`** | A list
(optional) of [partition statistics](#partition-statistics).
|
-| | | _required_ | **`next-row-id`** | A
`long` higher than all assigned row IDs; the next snapshot's `first-row-id`.
See [Row Lineage](#row-lineage).
|
-| | | _optional_ | **`encryption-keys`** | A list
(optional) of [encryption keys](#encryption-keys) used for table encryption. |
+=== "v1 - v3"
+ | v1 | v2 | v3 | Field |
Description |
+ | ---------- | ---------- |------------|-----------------------------|
------------|
+ | _required_ | _required_ | _required_ | **`format-version`** | An
integer version number for the format. Implementations must throw an exception
if a table’s version is higher than the supported version. |
+ | _optional_ | _required_ | _required_ | **`table-uuid`** | A
UUID that identifies the table, generated when the table is created.
Implementations must throw an exception if a table’s UUID does not match the
expected UUID after refreshing metadata. |
+ | _required_ | _required_ | _required_ | **`location`** | The
table’s base location. This is used by writers to determine where to store data
files, manifest files, and table metadata files. |
+ | | _required_ | _required_ | **`last-sequence-number`** | The
table’s highest assigned sequence number, a monotonically increasing long that
tracks the order of snapshots in a table. |
+ | _required_ | _required_ | _required_ | **`last-updated-ms`** |
Timestamp in milliseconds from the unix epoch when the table was last updated.
Each table metadata file should update this field just before writing. |
+ | _required_ | _required_ | _required_ | **`last-column-id`** | An
integer; the highest assigned column ID for the table. This is used to ensure
columns are always assigned an unused ID when evolving schemas. |
+ | _required_ | | | **`schema`** | The
table’s current schema. (**Deprecated**: use `schemas` and `current-schema-id`
instead) |
+ | _optional_ | _required_ | _required_ | **`schemas`** | A
list of schemas, stored as objects with `schema-id`. |
+ | _optional_ | _required_ | _required_ | **`current-schema-id`** | ID
of the table’s current schema. |
+ | _required_ | | | **`partition-spec`** | The
table’s current partition spec, stored as only fields. (**Deprecated**: use
`partition-specs` and `default-spec-id` instead) |
Review Comment:
Content drop: original deprecation description included "Note that this is
used by writers to partition data, but is not used when reading because reads
use the specs stored in manifest files." That sentence was removed in this PR.
It explains *why* the deprecated single `partition-spec` field was safe to
deprecate (readers never relied on it) and is useful context for anyone
implementing v1 readers.
##########
format/spec.md:
##########
@@ -643,32 +645,33 @@ Notes:
The `data_file` struct consists of the following fields:
-| v1 | v2 | v3 | Field id, name |
Type |
Description
|
-| ----------
|------------|------------|-----------------------------------|-----------------------------------------------------------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
-| | _required_ | _required_ | **`134 content`** |
`int` with meaning: `0: DATA`, `1: POSITION DELETES`, `2: EQUALITY DELETES` |
Type of content stored by the data file: data, equality deletes, or position
deletes (all v1 files are data files)
|
-| _required_ | _required_ | _required_ | **`100 file_path`** |
`string` |
Full URI for the file with FS scheme
|
-| _required_ | _required_ | _required_ | **`101 file_format`** |
`string` |
String file format name, `avro`, `orc`, `parquet`, or `puffin`
|
-| _required_ | _required_ | _required_ | **`102 partition`** |
`struct<...>` |
Partition data tuple, schema based on the partition spec output using partition
field ids for the struct field ids
|
-| _required_ | _required_ | _required_ | **`103 record_count`** |
`long` |
Number of records in this file, or the cardinality of a deletion vector
|
-| _required_ | _required_ | _required_ | **`104 file_size_in_bytes`** |
`long` |
Total file size in bytes
|
-| _required_ | | | ~~**`105 block_size_in_bytes`**~~ |
`long` |
**Deprecated. Always write a default in v1. Do not write in v2 or v3.**
|
-| _optional_ | | | ~~**`106 file_ordinal`**~~ |
`int` |
**Deprecated. Do not write.**
|
-| _optional_ | | | ~~**`107 sort_columns`**~~ |
`list<112: int>` |
**Deprecated. Do not write.**
|
-| _optional_ | _optional_ | _optional_ | **`108 column_sizes`** |
`map<117: int, 118: long>` |
Map from column id to the total size on disk of all regions that store the
column. Does not include bytes necessary to read other columns, like footers.
Leave null for row-oriented formats (Avro) |
-| _optional_ | _optional_ | _optional_ | **`109 value_counts`** |
`map<119: int, 120: long>` |
Map from column id to number of values in the column (including null and NaN
values)
|
-| _optional_ | _optional_ | _optional_ | **`110 null_value_counts`** |
`map<121: int, 122: long>` |
Map from column id to number of null values in the column
|
-| _optional_ | _optional_ | _optional_ | **`137 nan_value_counts`** |
`map<138: int, 139: long>` |
Map from column id to number of NaN values in the column
|
-| _optional_ | _optional_ | | ~~**`111 distinct_counts`**~~ |
`map<123: int, 124: long>` |
**Deprecated. Do not write.**
|
-| _optional_ | _optional_ | _optional_ | **`125 lower_bounds`** |
`map<126: int, 127: binary>` |
Map from column id to lower bound in the column serialized as binary [1]. Each
value must be less than or equal to all non-null, non-NaN values in the column
for the file [2] |
-| _optional_ | _optional_ | _optional_ | **`128 upper_bounds`** |
`map<129: int, 130: binary>` |
Map from column id to upper bound in the column serialized as binary [1]. Each
value must be greater than or equal to all non-null, non-Nan values in the
column for the file [2] |
-| _optional_ | _optional_ | _optional_ | **`131 key_metadata`** |
`binary` |
Implementation-specific key metadata for encryption
|
-| _optional_ | _optional_ | _optional_ | **`132 split_offsets`** |
`list<133: long>` |
Split offsets for the data file. For example, all row group offsets in a
Parquet file. Must be sorted ascending
|
-| | _optional_ | _optional_ | **`135 equality_ids`** |
`list<136: int>` |
Field ids used to determine row equality in equality delete files. Required
when `content=2` and should be null otherwise. Fields with ids listed in this
column must be present in the delete file |
-| _optional_ | _optional_ | _optional_ | **`140 sort_order_id`** |
`int` |
ID representing sort order for this file [3].
|
-| | | _optional_ | **`142 first_row_id`** |
`long` |
The `_row_id` for the first row in the data file. See [First Row ID
Inheritance](#first-row-id-inheritance)
|
-| | _optional_ | _optional_ | **`143 referenced_data_file`** |
`string` |
Fully qualified location (URI with FS scheme) of a data file that all deletes
reference [4]
|
-| | | _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]
|
+=== "v1 - v3"
+ | v1 | v2 | v3 | Field id, name
| Type |
Description |
+ | ----------
|------------|------------|-----------------------------------|-----------------------------------------------------------------------------|-------------|
+ | | _required_ | _required_ | **`134 content`**
| `int` with meaning: `0: DATA`, `1: POSITION DELETES`, `2: EQUALITY DELETES` |
Type of content stored by the data file: data, equality deletes, or position
deletes (all v1 files are data files) |
+ | _required_ | _required_ | _required_ | **`100 file_path`**
| `string` |
Full URI for the file with FS scheme |
+ | _required_ | _required_ | _required_ | **`101 file_format`**
| `string` |
String file format name, `avro`, `orc`, `parquet`, or `puffin` |
+ | _required_ | _required_ | _required_ | **`102 partition`**
| `struct<...>` |
Partition data tuple, schema based on the partition spec output using partition
field ids for the struct field ids |
+ | _required_ | _required_ | _required_ | **`103 record_count`**
| `long` |
Number of records in this file, or the cardinality of a deletion vector |
+ | _required_ | _required_ | _required_ | **`104 file_size_in_bytes`**
| `long` |
Total file size in bytes |
+ | _required_ | | | ~~**`105 block_size_in_bytes`**~~
| `long` |
**Deprecated. Always write a default in v1. Do not write in v2 or v3.** |
+ | _optional_ | | | ~~**`106 file_ordinal`**~~
| `int` |
**Deprecated. Do not write.** |
+ | _optional_ | | | ~~**`107 sort_columns`**~~
| `list<112: int>` |
**Deprecated. Do not write.** |
+ | _optional_ | _optional_ | _optional_ | **`108 column_sizes`**
| `map<117: int, 118: long>` |
Map from column id to the total size on disk of all regions that store the
column. Leave null for row-oriented formats (Avro) |
Review Comment:
Content drop: original description was "Map from column id to the total size
on disk of all regions that store the column. **Does not include bytes
necessary to read other columns, like footers.** Leave null for row-oriented
formats (Avro)". The bolded sentence was removed in this PR — it conveyed real
information about what this metric does and doesn't account for. Should be
restored if this PR is meant to be formatting-only.
##########
format/spec.md:
##########
@@ -921,33 +926,34 @@ The atomic operation used to commit metadata depends on
how tables are tracked a
Table metadata consists of the following fields:
-| v1 | v2 | v3 | Field |
Description
|
-| ---------- | ----------
|------------|-----------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
-| _required_ | _required_ | _required_ | **`format-version`** | An
integer version number for the format. Implementations must throw an exception
if a table's version is higher than the supported version.
|
-| _optional_ | _required_ | _required_ | **`table-uuid`** | A UUID
that identifies the table, generated when the table is created. Implementations
must throw an exception if a table's UUID does not match the expected UUID
after refreshing metadata.
|
-| _required_ | _required_ | _required_ | **`location`** | The
table's base location. This is used by writers to determine where to store data
files, manifest files, and table metadata files.
|
-| | _required_ | _required_ | **`last-sequence-number`** | The
table's highest assigned sequence number, a monotonically increasing long that
tracks the order of snapshots in a table.
|
-| _required_ | _required_ | _required_ | **`last-updated-ms`** |
Timestamp in milliseconds from the unix epoch when the table was last updated.
Each table metadata file should update this field just before writing.
|
-| _required_ | _required_ | _required_ | **`last-column-id`** | An
integer; the highest assigned column ID for the table. This is used to ensure
columns are always assigned an unused ID when evolving schemas.
|
-| _required_ | | | **`schema`** | The
table’s current schema. (**Deprecated**: use `schemas` and `current-schema-id`
instead)
|
-| _optional_ | _required_ | _required_ | **`schemas`** | A list
of schemas, stored as objects with `schema-id`.
|
-| _optional_ | _required_ | _required_ | **`current-schema-id`** | ID of
the table's current schema.
|
-| _required_ | | | **`partition-spec`** | The
table’s current partition spec, stored as only fields. Note that this is used
by writers to partition data, but is not used when reading because reads use
the specs stored in manifest files. (**Deprecated**: use `partition-specs` and
`default-spec-id` instead)
|
-| _optional_ | _required_ | _required_ | **`partition-specs`** | A list
of partition specs, stored as full partition spec objects.
|
-| _optional_ | _required_ | _required_ | **`default-spec-id`** | ID of
the "current" spec that writers should use by default.
|
-| _optional_ | _required_ | _required_ | **`last-partition-id`** | An
integer; the highest assigned partition field ID across all partition specs for
the table. This is used to ensure partition fields are always assigned an
unused ID when evolving specs.
|
-| _optional_ | _optional_ | _optional_ | **`properties`** | A
string to string map of table properties. This is used to control settings that
affect reading and writing and is not intended to be used for arbitrary
metadata. For example, `commit.retry.num-retries` is used to control the number
of commit retries.
|
-| _optional_ | _optional_ | _optional_ | **`current-snapshot-id`** | `long`
ID of the current table snapshot; must be the same as the current ID of the
`main` branch in `refs`.
|
-| _optional_ | _optional_ | _optional_ | **`snapshots`** | A list
of valid snapshots. Valid snapshots are snapshots for which all data files
exist in the file system. A data file must not be deleted from the file system
until the last snapshot in which it was listed is garbage collected.
|
-| _optional_ | _optional_ | _optional_ | **`snapshot-log`** | A list
(optional) of timestamp and snapshot ID pairs that encodes changes to the
current snapshot for the table. Each time the current-snapshot-id is changed, a
new entry should be added with the last-updated-ms and the new
current-snapshot-id. When snapshots are expired from the list of valid
snapshots, all entries before a snapshot that has expired should be removed.
|
-| _optional_ | _optional_ | _optional_ | **`metadata-log`** | A list
(optional) of timestamp and metadata file location pairs that encodes changes
to the previous metadata files for the table. Each time a new metadata file is
created, a new entry of the previous metadata file location should be added to
the list. Tables can be configured to remove oldest metadata log entries and
keep a fixed-size log of the most recent entries after a commit. |
-| _optional_ | _required_ | _required_ | **`sort-orders`** | A list
of sort orders, stored as full sort order objects.
|
-| _optional_ | _required_ | _required_ | **`default-sort-order-id`** | Default
sort order id of the table. Note that this could be used by writers, but is not
used when reading because reads use the specs stored in manifest files.
|
-| | _optional_ | _optional_ | **`refs`** | A map
of snapshot references. The map keys are the unique snapshot reference names in
the table, and the map values are snapshot reference objects. There is always a
`main` branch reference pointing to the `current-snapshot-id` even if the
`refs` map is null.
|
-| _optional_ | _optional_ | _optional_ | **`statistics`** | A list
(optional) of [table statistics](#table-statistics).
|
-| _optional_ | _optional_ | _optional_ | **`partition-statistics`** | A list
(optional) of [partition statistics](#partition-statistics).
|
-| | | _required_ | **`next-row-id`** | A
`long` higher than all assigned row IDs; the next snapshot's `first-row-id`.
See [Row Lineage](#row-lineage).
|
-| | | _optional_ | **`encryption-keys`** | A list
(optional) of [encryption keys](#encryption-keys) used for table encryption. |
+=== "v1 - v3"
+ | v1 | v2 | v3 | Field |
Description |
+ | ---------- | ---------- |------------|-----------------------------|
------------|
+ | _required_ | _required_ | _required_ | **`format-version`** | An
integer version number for the format. Implementations must throw an exception
if a table’s version is higher than the supported version. |
+ | _optional_ | _required_ | _required_ | **`table-uuid`** | A
UUID that identifies the table, generated when the table is created.
Implementations must throw an exception if a table’s UUID does not match the
expected UUID after refreshing metadata. |
+ | _required_ | _required_ | _required_ | **`location`** | The
table’s base location. This is used by writers to determine where to store data
files, manifest files, and table metadata files. |
+ | | _required_ | _required_ | **`last-sequence-number`** | The
table’s highest assigned sequence number, a monotonically increasing long that
tracks the order of snapshots in a table. |
+ | _required_ | _required_ | _required_ | **`last-updated-ms`** |
Timestamp in milliseconds from the unix epoch when the table was last updated.
Each table metadata file should update this field just before writing. |
+ | _required_ | _required_ | _required_ | **`last-column-id`** | An
integer; the highest assigned column ID for the table. This is used to ensure
columns are always assigned an unused ID when evolving schemas. |
+ | _required_ | | | **`schema`** | The
table’s current schema. (**Deprecated**: use `schemas` and `current-schema-id`
instead) |
+ | _optional_ | _required_ | _required_ | **`schemas`** | A
list of schemas, stored as objects with `schema-id`. |
+ | _optional_ | _required_ | _required_ | **`current-schema-id`** | ID
of the table’s current schema. |
+ | _required_ | | | **`partition-spec`** | The
table’s current partition spec, stored as only fields. (**Deprecated**: use
`partition-specs` and `default-spec-id` instead) |
+ | _optional_ | _required_ | _required_ | **`partition-specs`** | A
list of partition specs, stored as full partition spec objects. |
+ | _optional_ | _required_ | _required_ | **`default-spec-id`** | ID
of the "current" spec that writers should use by default. |
+ | _optional_ | _required_ | _required_ | **`last-partition-id`** | An
integer; the highest assigned partition field ID across all partition specs for
the table. This is used to ensure partition fields are always assigned an
unused ID when evolving specs. |
+ | _optional_ | _optional_ | _optional_ | **`properties`** | A
string to string map of table properties. This is used to control settings that
affect reading and writing and is not intended to be used for arbitrary
metadata. |
Review Comment:
Content drop: original ended with "For example, `commit.retry.num-retries`
is used to control the number of commit retries." The example clarified what
kinds of properties this map is for (vs. arbitrary user metadata). The example
value is also referenced again at `format/spec.md:1548` in the JSON example, so
deleting it here orphans that reference.
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