Fix the pool fix (#176)

* Always listen to the compiler

* Its fine

src/config.rs

@@ -3,8 +3,8 @@ use arc_swap::ArcSwap;
 use log::{error, info};
 use once_cell::sync::Lazy;
 use serde_derive::{Deserialize, Serialize};
-use std::collections::{HashMap, HashSet};
-use std::hash::{Hash, Hasher};
+use std::collections::{BTreeMap, HashMap, HashSet};
+use std::hash::Hash;
 use std::path::Path;
 use std::sync::Arc;
 use tokio::fs::File;
@@ -250,7 +250,7 @@ impl ToString for PoolMode {
     }
 }
 
-#[derive(Serialize, Deserialize, Debug, Clone, PartialEq, Eq)]
+#[derive(Serialize, Deserialize, Debug, Clone, PartialEq, Eq, Hash)]
 pub struct Pool {
     #[serde(default = "Pool::default_pool_mode")]
     pub pool_mode: PoolMode,
@@ -267,29 +267,8 @@ pub struct Pool {
     pub connect_timeout: u64,
 
     pub sharding_function: String,
-    pub shards: HashMap<String, Shard>,
-    pub users: HashMap<String, User>,
-}
-
-impl Hash for Pool {
-    fn hash<H: Hasher>(&self, state: &mut H) {
-        self.pool_mode.hash(state);
-        self.default_role.hash(state);
-        self.query_parser_enabled.hash(state);
-        self.primary_reads_enabled.hash(state);
-        self.sharding_function.hash(state);
-        self.connect_timeout.hash(state);
-
-        for (key, value) in &self.shards {
-            key.hash(state);
-            value.hash(state);
-        }
-
-        for (key, value) in &self.users {
-            key.hash(state);
-            value.hash(state);
-        }
-    }
+    pub shards: BTreeMap<String, Shard>,
+    pub users: BTreeMap<String, User>,
 }
 
 impl Pool {
@@ -302,8 +281,8 @@ impl Default for Pool {
     fn default() -> Pool {
         Pool {
             pool_mode: Pool::default_pool_mode(),
-            shards: HashMap::from([(String::from("1"), Shard::default())]),
-            users: HashMap::default(),
+            shards: BTreeMap::from([(String::from("1"), Shard::default())]),
+            users: BTreeMap::default(),
             default_role: String::from("any"),
             query_parser_enabled: false,
             primary_reads_enabled: false,

src/pool.rs

@@ -108,13 +108,25 @@ impl ConnectionPool {
         for (pool_name, pool_config) in &config.pools {
             let changed = pools_hash.insert(pool_config.clone());
 
-            if !changed {
-                info!("[db: {}] has not changed", pool_name);
-                continue;
-            }
-
             // There is one pool per database/user pair.
             for (_, user) in &pool_config.users {
+                // If the pool hasn't changed, get existing reference and insert it into the new_pools.
+                // We replace all pools at the end, but if the reference is kept, the pool won't get re-created (bb8).
+                if !changed {
+                    match get_pool(pool_name.clone(), user.username.clone()) {
+                        Some(pool) => {
+                            info!(
+                                "[pool: {}][user: {}] has not changed",
+                                pool_name, user.username
+                            );
+                            new_pools
+                                .insert((pool_name.clone(), user.username.clone()), pool.clone());
+                            continue;
+                        }
+                        None => (),
+                    }
+                }
+
                 info!(
                     "[pool: {}][user: {}] creating new pool",
                     pool_name, user.username