[HDDS-6486] Add new container schema v3 definitions.

• Type: Sub-task
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 1.3.0
• Labels: pull-request-available
• Assignee: Mark Gui
• Reporter: Mark Gui
• Created: 22/Mar/22 09:39
• Updated: 26/Apr/24 12:13
• Resolved: 07/Apr/22 06:31

Description

Add definition classes for rocksdb-merge, thus we have a new container schema – schemaV3.

After rocksdb-merge, we have the metadata of multiple containers into a central per-disk rocksdb instances, so we should add prefix to their metadata KVs, here is a comparison of the old schemaV2 v.s. schemaV3:

SchemaV2

Table Name/ColumnFamily	KeyValue
block_data	<LocalID, BlockData>
metadata	<MetadataPrefix, MetadataValue>
delete_txns	<TxnID, DeletedBlocksTransaction>

SchemaV3

Table Name/ColumnFamily	KeyValue
block_data	<ContainerID#LocalID, BlockData>
metadata	<ContainerID#MetadataPrefix, MetadataValue>
delete_txns	<ContainerID#TxnID, DeletedBlocksTransaction>

The containerID should be of fixed-length, then the iteration of a specific container metadata will be optimized using rocksdb "Prefix-Seek" feature: https://github.com/facebook/rocksdb/wiki/Prefix-Seek.

We need to define new classes such as:

• DatanodeSchemaThreeDBDefinition
• DatanodeStoreSchemaThreeImpl

Issue Links

• relates to: HDDS-10762 Review/discuss SchemaV3's prefix_seek optimization
• links to: GitHub Pull Request #3253