Struct salsa::Runtime

pub struct Runtime { /* fields omitted */ }

The salsa runtime stores the storage for all queries as well as tracking the query stack and dependencies between cycles.

Each new runtime you create (e.g., via Runtime::new or Runtime::default) will have an independent set of query storage associated with it. Normally, therefore, you only do this once, at the start of your application.

Implementations

impl Runtime

pub fn new() -> Self

Create a new runtime; equivalent to Self::default. This is used when creating a new database.

pub fn synthetic_write(&mut self, durability: Durability)

A “synthetic write” causes the system to act as though some input of durability durability has changed. This is mostly useful for profiling scenarios, but it also has interactions with garbage collection. In general, a synthetic write to durability level D will cause the system to fully trace all queries of durability level D and below. When running a GC, then:

• Synthetic writes will cause more derived values to be retained. This is because derived values are only retained if they are traced, and a synthetic write can cause more things to be traced.
• Synthetic writes can cause more interned values to be collected. This is because interned values can only be collected if they were not yet traced in the current revision. Therefore, if you issue a synthetic write, execute some query Q, and then start collecting interned values, you will be able to recycle interned values not used in Q.

In general, then, one can do a “full GC” that retains only those things that are used by some query Q by (a) doing a synthetic write at Durability::HIGH, (b) executing the query Q and then (c) doing a sweep.

WARNING: Just like an ordinary write, this method triggers cancellation. If you invoke it while a snapshot exists, it will block until that snapshot is dropped – if that snapshot is owned by the current thread, this could trigger deadlock.

pub fn id(&self) -> RuntimeId

The unique identifier attached to this SalsaRuntime. Each snapshotted runtime has a distinct identifier.

pub fn active_query(&self) -> Option<DatabaseKeyIndex>

Returns the database-key for the query that this thread is actively executing (if any).

pub fn report_untracked_read(&self)

Reports that the query depends on some state unknown to salsa.

Queries which report untracked reads will be re-executed in the next revision.

pub fn report_synthetic_read(&self, durability: Durability)

Acts as though the current query had read an input with the given durability; this will force the current query’s durability to be at most durability.

This is mostly useful to control the durability level for on-demand inputs.

Trait Implementations

impl Debug for Runtime

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

Formats the value using the given formatter.

impl Default for Runtime

fn default() -> Self

Returns the “default value” for a type.