Struct DurableCache

pub struct DurableCache<C: DurableCacheCodec> {
    pub(crate) since_handle: SinceHandle<C::KeyCodec, C::ValCodec, u64, i64, i64>,
    pub(crate) write: WriteHandle<C::KeyCodec, C::ValCodec, u64, i64>,
    pub(crate) subscribe: Subscribe<C::KeyCodec, C::ValCodec, u64, i64>,
    pub(crate) local: BTreeMap<C::Key, LocalVal<C>>,
    pub(crate) local_progress: u64,
}

Fields

since_handle: SinceHandle<C::KeyCodec, C::ValCodec, u64, i64, i64>

write: WriteHandle<C::KeyCodec, C::ValCodec, u64, i64>

subscribe: Subscribe<C::KeyCodec, C::ValCodec, u64, i64>

local: BTreeMap<C::Key, LocalVal<C>>

local_progress: u64

Implementations

impl<C: DurableCacheCodec> DurableCache<C>

pub async fn new( persist: &PersistClient, shard_id: ShardId, purpose: &str, ) -> Self

Opens a DurableCache using shard shard_id.

pub(crate) async fn sync_to(&mut self, progress: Option<u64>) -> u64

pub fn get_local(&self, key: &C::Key) -> Option<&C::Val>

Get and return the value associated with key if it exists, without syncing with the durable store.

pub async fn get( &mut self, key: &C::Key, val_fn: impl FnOnce() -> C::Val, ) -> &C::Val

Get and return the value associated with key, syncing with the durable store if necessary. If key does not exist, then a value is computed via val_fn and durably stored in the cache.

pub fn entries_local(&self) -> impl Iterator<Item = (&C::Key, &C::Val)>

Return all entries stored in the cache, without syncing with the durable store.

pub async fn set(&mut self, key: &C::Key, value: Option<&C::Val>)

Durably set key to value. A value of None deletes the entry from the cache.

Failures will update the cache and retry until the cache is written successfully.

pub async fn set_many(&mut self, entries: &[(&C::Key, Option<&C::Val>)])

Durably set multiple key-value pairs in entries. Values of None deletes the corresponding entries from the cache.

Failures will update the cache and retry until the cache is written successfully.

pub async fn try_set( &mut self, key: &C::Key, value: Option<&C::Val>, ) -> Result<(), Error>

Tries to durably set key to value. A value of None deletes the entry from the cache.

On both successes and failures, the cache will update its contents with the most recent updates from the durable store.

pub async fn try_set_many( &mut self, entries: &[(&C::Key, Option<&C::Val>)], ) -> Result<(), Error>

Tries to durably set multiple key-value pairs in entries. Values of None deletes the corresponding entries from the cache.

On both successes and failures, the cache will update its contents with the most recent updates from the durable store.

pub(crate) async fn compare_and_append<I>( &mut self, updates: I, write_ts: u64, ) -> Result<u64, UpperMismatch<u64>>

where I: IntoIterator<Item = ((C::KeyCodec, C::ValCodec), i64)>,

Applies updates to the cache at write_ts. See WriteHandle::compare_and_append for more details.

This method will also downgrade the critical since of the underlying persist shard on success.

pub async fn dangerous_compact_shard( &self, fuel: impl Fn() -> usize, wait: impl Fn() -> Duration, )

Forcibly compacts the shard backing this cache. See mz_persist_client::cli::admin::dangerous_force_compaction_and_break_pushdown.

Trait Implementations

impl<C: Debug + DurableCacheCodec> Debug for DurableCache<C>

where C::KeyCodec: Debug, C::ValCodec: Debug, C::Key: Debug,

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.