Prepared statement cache eviction (#562)

Author: levkk

integration/rust/tests/integration/prepared.rs

@@ -1,6 +1,8 @@
+use std::time::Duration;
+
 use rust::setup::*;
 use sqlx::{Executor, Row, postgres::PgPoolOptions, types::BigDecimal};
-use tokio::spawn;
+use tokio::{spawn, time::sleep};
 
 #[tokio::test]
 async fn test_prepared_cache() {
@@ -251,6 +253,9 @@ async fn test_prepard_cache_eviction() {
         conn.close().await;
     }
 
+    // Let maintenance clean up.
+    sleep(Duration::from_secs(2)).await;
+
     // Evicted only when clients disconnect or manually close the statement.
     let prepared = admin.fetch_all("SHOW PREPARED").await.unwrap();
     assert_eq!(prepared.len(), 2);

pgdog/src/frontend/client/mod.rs

@@ -483,7 +483,6 @@ impl Client {
         let config = config::config();
         // Configure prepared statements cache.
         self.prepared_statements.level = config.prepared_statements();
-        self.prepared_statements.capacity = config.config.general.prepared_statements_limit;
         self.timeouts = Timeouts::from_config(&config.config.general);
 
         while !self.client_request.full() {