Module statement_cache 

Prepared statement caching with LRU eviction.

This module provides automatic caching of prepared statements to improve performance for repeated query execution. The cache uses an LRU (Least Recently Used) eviction policy to manage memory and server-side resources.

Lifecycle

1. First execution of a parameterized query calls sp_prepare, returning a handle
2. The handle is cached by SQL hash; subsequent executions use sp_execute
3. When the cache is full, LRU eviction calls sp_unprepare for evicted handles
4. Pool reset (sp_reset_connection) invalidates all handles, clearing the cache
5. Connection close implicitly releases all server-side handles

Structs

PreparedStatement

A cached prepared statement.

StatementCache

LRU cache for prepared statements.

StatementCacheConfig

Configuration for statement caching.

Constants

DEFAULT_MAX_STATEMENTS

Default maximum number of prepared statements to cache per connection.

Functions

hash_sql

Hash SQL text for cache lookup.