Struct SchemaCache 

pub struct SchemaCache {
    keyspaces: Vec<KeyspaceMetadata>,
    tables: HashMap<String, Vec<TableMetadata>>,
    udts: HashMap<String, Vec<UdtMetadata>>,
    functions: HashMap<String, Vec<FunctionMetadata>>,
    aggregates: HashMap<String, Vec<AggregateMetadata>>,
    last_refresh: Option<Instant>,
    ttl: Duration,
}

Cached schema metadata for a CQL cluster.

Stores keyspaces, tables, UDTs, functions, and aggregates fetched from the cluster. Lookup methods are synchronous — callers must call refresh() to populate or update the cache.

Fields

keyspaces: Vec<KeyspaceMetadata>

All keyspaces in the cluster.

tables: HashMap<String, Vec<TableMetadata>>

Tables indexed by keyspace name.

udts: HashMap<String, Vec<UdtMetadata>>

UDTs indexed by keyspace name.

functions: HashMap<String, Vec<FunctionMetadata>>

Functions indexed by keyspace name.

aggregates: HashMap<String, Vec<AggregateMetadata>>

Aggregates indexed by keyspace name.

last_refresh: Option<Instant>

When the cache was last successfully refreshed.

ttl: Duration

How long before the cache is considered stale.

Implementations

impl SchemaCache

pub fn new() -> Self

Create a new, empty cache with the default TTL of 30 seconds.

pub fn with_ttl(ttl: Duration) -> Self

Create a new, empty cache with a custom TTL.

pub fn is_stale(&self) -> bool

Returns true if the cache has never been refreshed or its TTL has elapsed.

pub fn invalidate(&mut self)

Force the cache to appear stale so the next access triggers a refresh.

pub async fn refresh(&mut self, session: &CqlSession) -> Result<()>

Refresh the cache by fetching all schema metadata from the cluster.

Fetches all keyspaces first, then tables, UDTs, functions, and aggregates for each keyspace in parallel (sequentially per keyspace for simplicity — a future optimisation could use join_all).

pub fn keyspace_names(&self) -> Vec<&str>

Return the names of all cached keyspaces.

pub fn table_names(&self, keyspace: &str) -> Vec<&str>

Return the names of all tables in keyspace.

Returns an empty Vec if the keyspace is unknown.

pub fn column_names(&self, keyspace: &str, table: &str) -> Vec<&str>

Return the names of all columns in keyspace.table.

Returns an empty Vec if the keyspace or table is unknown.

pub fn udt_names(&self, keyspace: &str) -> Vec<&str>

Return the names of all UDTs in keyspace.

Returns an empty Vec if the keyspace is unknown.

pub fn function_names(&self, keyspace: &str) -> Vec<&str>

Return the names of all functions in keyspace.

Returns an empty Vec if the keyspace is unknown.

pub fn aggregate_names(&self, keyspace: &str) -> Vec<&str>

Return the names of all aggregates in keyspace.

Returns an empty Vec if the keyspace is unknown.

Trait Implementations

impl Default for SchemaCache

fn default() -> Self

Returns the “default value” for a type.