Struct TombstoneManager 

pub struct TombstoneManager {
    kv_backend: KvBackendRef,
    tombstone_prefix: String,
}

TombstoneManager provides the ability to:

• logically delete values
• restore the deleted values

The tombstone mechanism is primarily used for table metadata deletion. When a table is logically deleted, its associated metadata keys are moved to a tombstone area by prepending a prefix (default is __tombstone/).

All involved keys in the tombstone mechanism:

• __table_name/{catalog}/{schema}/{table_name}: Maps table name to table ID.
• __table_info/{table_id}: Stores table information/metadata.
• __table_route/{table_id}: Stores table routing information.
• __table_repart/{table_id}: Stores table repartition information.
• __dn_table/{datanode_id}/{table_id}: Maps datanodes to table regions.
• __topic_region/{topic_name}/{region_id}: Maps regions to WAL topics.

These keys are moved to:

• __tombstone/__table_name/...
• __tombstone/__table_info/...
• __tombstone/__table_route/...
• __tombstone/__table_repart/...
• __tombstone/__dn_table/...
• __tombstone/__topic_region/...

Fields

kv_backend: KvBackendRef

tombstone_prefix: String

Implementations

impl TombstoneManager

pub fn new(kv_backend: KvBackendRef) -> Self

Returns TombstoneManager.

pub fn new_with_prefix(kv_backend: KvBackendRef, prefix: &str) -> Self

Returns TombstoneManager with a custom tombstone prefix.

pub fn to_tombstone(&self, key: &[u8]) -> Vec<u8>

pub fn strip_tombstone_prefix<'a>( &self, tombstone_key: &'a [u8], ) -> Result<&'a [u8]>

Removes the tombstone prefix from a tombstoned key.

pub async fn get(&self, key: &[u8]) -> Result<Option<KeyValue>>

Gets a single tombstoned value by its original key.

pub async fn batch_get( &self, keys: &[Vec<u8>], ) -> Result<HashMap<Vec<u8>, KeyValue>>

Gets tombstoned values by their original keys.

pub fn tombstones(&self) -> BoxStream<'static, Result<KeyValue>>

Streams all tombstoned key-value pairs.

pub fn tombstoned_table_names(&self) -> BoxStream<'static, Result<KeyValue>>

Streams tombstoned table-name entries only.

fn scan_prefix(&self, prefix: Vec<u8>) -> BoxStream<'static, Result<KeyValue>>

Streams tombstoned entries under the provided prefix.

fn build_move_value_txn( &self, src_key: Vec<u8>, value: Vec<u8>, dest_key: Vec<u8>, ) -> (Txn, impl FnMut(&mut TxnOpGetResponseSet) -> Option<Vec<u8>>)

Moves value to dest_key.

Puts value to dest_key if the value of src_key equals value.

Otherwise retrieves the value of src_key.

async fn move_values_inner( &self, keys: &[Vec<u8>], dest_keys: &[Vec<u8>], ) -> Result<usize>

fn max_txn_ops(&self) -> usize

async fn move_values( &self, keys: Vec<Vec<u8>>, dest_keys: Vec<Vec<u8>>, ) -> Result<usize>

Moves values to dest_key.

Returns the number of keys that were moved.

pub async fn create(&self, keys: Vec<Vec<u8>>) -> Result<usize>

Creates tombstones for keys.

Preforms to:

• deletes origin values.
• stores tombstone values.

Returns the number of keys that were moved.

pub async fn restore(&self, keys: Vec<Vec<u8>>) -> Result<usize>

Restores tombstones for keys.

Preforms to:

• restore origin value.
• deletes tombstone values.

Returns the number of keys that were restored.

pub async fn delete(&self, keys: Vec<Vec<u8>>) -> Result<usize>

Deletes tombstones values for the specified keys.

Returns the number of keys that were deleted.