flyrain commented on code in PR #6002: URL: https://github.com/apache/iceberg/pull/6002#discussion_r1006133472
########## format/spec.md: ########## @@ -463,8 +464,9 @@ When a file is added to the dataset, its manifest entry should store the snapsho 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 a sequence number to the entry and makes the snapshot id optional. Both fields, `sequence_number` and `snapshot_id`, 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 [2]. -The `sequence_number` field represents the data sequence number and must never change after a file is added to the dataset. +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 `file_sequence_number` field represents the sequence number of the snapshot that added the file and must also remain unchanged upon assigning at commit. Review Comment: I feel a bit hard to understand the difference between them. Can we add something like? ``` The `sequence_number` will use the one from original files in the case of compaction, but the `file_sequence_number` will alway be one from the snapshot added the file. `file_sequence_number` of a file may be larger or the same as its `sequence_number`. ``` -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
