Struct StatementCache 

pub struct StatementCache { /* private fields */ }

LRU cache for prepared statements.

This cache automatically evicts the least recently used statements when the maximum capacity is reached. Evicted statements should have their server-side handles released via sp_unprepare.

Implementations

impl StatementCache

pub fn new(max_size: usize) -> Self

Create a new statement cache with the specified maximum size.

Panics

Panics if max_size is 0.

pub fn with_default_size() -> Self

Create a new statement cache with the default maximum size.

pub fn get(&mut self, sql: &str) -> Option<i32>

Look up a prepared statement by SQL text.

Returns Some(handle) if the statement is cached, None otherwise. This updates the LRU order.

pub fn peek(&self, sql: &str) -> Option<&PreparedStatement>

Peek at a prepared statement without updating LRU order.

pub fn insert(&mut self, stmt: PreparedStatement) -> Option<PreparedStatement>

Insert a prepared statement into the cache.

Returns the evicted statement if one was removed due to capacity.

pub fn remove(&mut self, sql: &str) -> Option<PreparedStatement>

Remove a prepared statement from the cache.

Returns the removed statement if it was present.

pub fn clear(&mut self) -> impl Iterator<Item = PreparedStatement> + '_

Clear all cached statements.

Returns an iterator over all removed statements. The caller should call sp_unprepare for each returned statement.

pub fn len(&self) -> usize

Get the number of cached statements.

pub fn is_empty(&self) -> bool

Check if the cache is empty.

pub fn max_size(&self) -> usize

Get the maximum cache size.

pub fn hits(&self) -> u64

Get the number of cache hits.

pub fn misses(&self) -> u64

Get the number of cache misses.

pub fn hit_ratio(&self) -> f64

Get the cache hit ratio (0.0 to 1.0).

pub fn reset_stats(&mut self)

Reset cache statistics.

Trait Implementations

impl Debug for StatementCache

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

Formats the value using the given formatter.

impl Default for StatementCache

fn default() -> Self

Returns the “default value” for a type.