Struct PreparedStatementCache 

pub struct PreparedStatementCache { /* private fields */ }

A cache for prepared statements.

This cache stores prepared statement metadata and tracks usage patterns to optimize database interactions. The actual statement handles are managed by the database driver.

Features

• LRU eviction when capacity is reached
• Usage statistics for monitoring
• Thread-safe with read-write locking
• Automatic cleanup of stale entries

Example

use prax_query::db_optimize::PreparedStatementCache;

let cache = PreparedStatementCache::new(100);

// Register a prepared statement
let entry = cache.get_or_create("find_user_by_email", || {
    "SELECT * FROM users WHERE email = $1".to_string()
});

// Check cache stats
let stats = cache.stats();
println!("Hit rate: {:.1}%", stats.hit_rate());

Implementations

impl PreparedStatementCache

pub fn new(capacity: usize) -> Self

Create a new cache with the specified capacity.

pub fn get_or_create<F>(&self, name: &str, generator: F) -> CachedStatement

where F: FnOnce() -> String,

Get or create a prepared statement entry.

If the statement is cached, returns the cached entry and increments hit count. Otherwise, calls the generator function, caches the result, and returns it.

pub fn contains(&self, name: &str) -> bool

Check if a statement is cached.

pub fn stats(&self) -> PreparedStatementStats

Get cache statistics.

pub fn clear(&self)

Clear the cache.

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 record_use(&self, name: &str)

Update statement usage (call after executing).

pub fn set_handle(&self, name: &str, handle: u64)

Set a database-specific handle for a statement.

Trait Implementations

impl Default for PreparedStatementCache

fn default() -> Self

Returns the “default value” for a type.