Handle and track startup parameters (#478)

* User server parameters struct instead of server info bytesmut

* Refactor to use hashmap for all params and add server parameters to client

* Sync parameters on client server checkout

* minor refactor

* update client side parameters when changed

* Move the SET statement logic from the C packet to the S packet.

* trigger build

* revert validation changes

* remove comment

* Try fix

* Reset cleanup state after sync

* fix server version test

* Track application name through client life for stats

* Add tests

* minor refactoring

* fmt

* fix

* fmt

src/admin.rs

@@ -1,4 +1,5 @@
 use crate::pool::BanReason;
+use crate::server::ServerParameters;
 use crate::stats::pool::PoolStats;
 use bytes::{Buf, BufMut, BytesMut};
 use log::{error, info, trace};
@@ -17,16 +18,16 @@ use crate::pool::ClientServerMap;
 use crate::pool::{get_all_pools, get_pool};
 use crate::stats::{get_client_stats, get_server_stats, ClientState, ServerState};
 
-pub fn generate_server_info_for_admin() -> BytesMut {
+pub fn generate_server_parameters_for_admin() -> ServerParameters {
-    let mut server_info = BytesMut::new();
+    let mut server_parameters = ServerParameters::new();
 
-    server_info.put(server_parameter_message("application_name", ""));
+    server_parameters.set_param("application_name".to_string(), "".to_string(), true);
-    server_info.put(server_parameter_message("client_encoding", "UTF8"));
+    server_parameters.set_param("client_encoding".to_string(), "UTF8".to_string(), true);
-    server_info.put(server_parameter_message("server_encoding", "UTF8"));
+    server_parameters.set_param("server_encoding".to_string(), "UTF8".to_string(), true);
-    server_info.put(server_parameter_message("server_version", VERSION));
+    server_parameters.set_param("server_version".to_string(), VERSION.to_string(), true);
-    server_info.put(server_parameter_message("DateStyle", "ISO, MDY"));
+    server_parameters.set_param("DateStyle".to_string(), "ISO, MDY".to_string(), true);
 
-    server_info
+    server_parameters
 }
 
 /// Handle admin client.

src/client.rs

@@ -12,7 +12,7 @@ use tokio::net::TcpStream;
 use tokio::sync::broadcast::Receiver;
 use tokio::sync::mpsc::Sender;
 
-use crate::admin::{generate_server_info_for_admin, handle_admin};
+use crate::admin::{generate_server_parameters_for_admin, handle_admin};
 use crate::auth_passthrough::refetch_auth_hash;
 use crate::config::{
     get_config, get_idle_client_in_transaction_timeout, get_prepared_statements, Address, PoolMode,
@@ -22,7 +22,7 @@ use crate::messages::*;
 use crate::plugins::PluginOutput;
 use crate::pool::{get_pool, ClientServerMap, ConnectionPool};
 use crate::query_router::{Command, QueryRouter};
-use crate::server::Server;
+use crate::server::{Server, ServerParameters};
 use crate::stats::{ClientStats, ServerStats};
 use crate::tls::Tls;
 
@@ -96,8 +96,8 @@ pub struct Client<S, T> {
     /// Postgres user for this client (This comes from the user in the connection string)
     username: String,
 
-    /// Application name for this client (defaults to pgcat)
+    /// Server startup and session parameters that we're going to track
-    application_name: String,
+    server_parameters: ServerParameters,
 
     /// Used to notify clients about an impending shutdown
     shutdown: Receiver<()>,
@@ -502,7 +502,7 @@ where
         };
 
         // Authenticate admin user.
-        let (transaction_mode, server_info) = if admin {
+        let (transaction_mode, mut server_parameters) = if admin {
             let config = get_config();
 
             // Compare server and client hashes.
@@ -521,7 +521,7 @@ where
                 return Err(error);
             }
 
-            (false, generate_server_info_for_admin())
+            (false, generate_server_parameters_for_admin())
         }
         // Authenticate normal user.
         else {
@@ -654,13 +654,16 @@ where
                 }
             }
 
-            (transaction_mode, pool.server_info())
+            (transaction_mode, pool.server_parameters())
         };
 
+        // Update the parameters to merge what the application sent and what's originally on the server
+        server_parameters.set_from_hashmap(&parameters, false);
+
         debug!("Password authentication successful");
 
         auth_ok(&mut write).await?;
-        write_all(&mut write, server_info).await?;
+        write_all(&mut write, (&server_parameters).into()).await?;
         backend_key_data(&mut write, process_id, secret_key).await?;
         ready_for_query(&mut write).await?;
 
@@ -690,7 +693,7 @@ where
             last_server_stats: None,
             pool_name: pool_name.clone(),
             username: username.clone(),
-            application_name: application_name.to_string(),
+            server_parameters,
             shutdown,
             connected_to_server: false,
             prepared_statements: HashMap::new(),
@@ -725,7 +728,7 @@ where
             last_server_stats: None,
             pool_name: String::from("undefined"),
             username: String::from("undefined"),
-            application_name: String::from("undefined"),
+            server_parameters: ServerParameters::new(),
             shutdown,
             connected_to_server: false,
             prepared_statements: HashMap::new(),
@@ -774,8 +777,11 @@ where
         let mut prepared_statement = None;
         let mut will_prepare = false;
 
-        let client_identifier =
+        let client_identifier = ClientIdentifier::new(
-            ClientIdentifier::new(&self.application_name, &self.username, &self.pool_name);
+            &self.server_parameters.get_application_name(),
+            &self.username,
+            &self.pool_name,
+        );
 
         // Our custom protocol loop.
         // We expect the client to either start a transaction with regular queries
@@ -1115,10 +1121,7 @@ where
                 server.address()
             );
 
-            // TODO: investigate other parameters and set them too.
+            server.sync_parameters(&self.server_parameters).await?;
-
-            // Set application_name.
-            server.set_name(&self.application_name).await?;
 
             let mut initial_message = Some(message);
 
@@ -1296,7 +1299,9 @@ where
                         if !server.in_transaction() {
                             // Report transaction executed statistics.
                             self.stats.transaction();
-                            server.stats().transaction(&self.application_name);
+                            server
+                                .stats()
+                                .transaction(&self.server_parameters.get_application_name());
 
                             // Release server back to the pool if we are in transaction mode.
                             // If we are in session mode, we keep the server until the client disconnects.
@@ -1446,7 +1451,9 @@ where
 
                         if !server.in_transaction() {
                             self.stats.transaction();
-                            server.stats().transaction(&self.application_name);
+                            server
+                                .stats()
+                                .transaction(&self.server_parameters.get_application_name());
 
                             // Release server back to the pool if we are in transaction mode.
                             // If we are in session mode, we keep the server until the client disconnects.
@@ -1495,7 +1502,9 @@ where
 
                         if !server.in_transaction() {
                             self.stats.transaction();
-                            server.stats().transaction(&self.application_name);
+                            server
+                                .stats()
+                                .transaction(self.server_parameters.get_application_name());
 
                             // Release server back to the pool if we are in transaction mode.
                             // If we are in session mode, we keep the server until the client disconnects.
@@ -1547,7 +1556,9 @@ where
 
                 Err(Error::ClientError(format!(
                     "Invalid pool name {{ username: {}, pool_name: {}, application_name: {} }}",
-                    self.pool_name, self.username, self.application_name
+                    self.pool_name,
+                    self.username,
+                    self.server_parameters.get_application_name()
                 )))
             }
         }
@@ -1704,7 +1715,7 @@ where
         client_stats.query();
         server.stats().query(
             Instant::now().duration_since(query_start).as_millis() as u64,
-            &self.application_name,
+            &self.server_parameters.get_application_name(),
         );
 
         Ok(())
@@ -1733,38 +1744,18 @@ where
         pool: &ConnectionPool,
         client_stats: &ClientStats,
     ) -> Result<BytesMut, Error> {
-        if pool.settings.user.statement_timeout > 0 {
+        let statement_timeout_duration = match pool.settings.user.statement_timeout {
-            match tokio::time::timeout(
+            0 => tokio::time::Duration::MAX,
-                tokio::time::Duration::from_millis(pool.settings.user.statement_timeout),
+            timeout => tokio::time::Duration::from_millis(timeout),
-                server.recv(),
+        };
-            )
+
-            .await
+        match tokio::time::timeout(
-            {
+            statement_timeout_duration,
-                Ok(result) => match result {
+            server.recv(Some(&mut self.server_parameters)),
-                    Ok(message) => Ok(message),
+        )
-                    Err(err) => {
+        .await
-                        pool.ban(address, BanReason::MessageReceiveFailed, Some(client_stats));
+        {
-                        error_response_terminal(
+            Ok(result) => match result {
-                            &mut self.write,
-                            &format!("error receiving data from server: {:?}", err),
-                        )
-                        .await?;
-                        Err(err)
-                    }
-                },
-                Err(_) => {
-                    error!(
-                        "Statement timeout while talking to {:?} with user {}",
-                        address, pool.settings.user.username
-                    );
-                    server.mark_bad();
-                    pool.ban(address, BanReason::StatementTimeout, Some(client_stats));
-                    error_response_terminal(&mut self.write, "pool statement timeout").await?;
-                    Err(Error::StatementTimeout)
-                }
-            }
-        } else {
-            match server.recv().await {
                 Ok(message) => Ok(message),
                 Err(err) => {
                     pool.ban(address, BanReason::MessageReceiveFailed, Some(client_stats));
@@ -1775,6 +1766,16 @@ where
                     .await?;
                     Err(err)
                 }
+            },
+            Err(_) => {
+                error!(
+                    "Statement timeout while talking to {:?} with user {}",
+                    address, pool.settings.user.username
+                );
+                server.mark_bad();
+                pool.ban(address, BanReason::StatementTimeout, Some(client_stats));
+                error_response_terminal(&mut self.write, "pool statement timeout").await?;
+                Err(Error::StatementTimeout)
             }
         }
     }

src/messages.rs

@@ -144,6 +144,10 @@ where
     bytes.put_slice(user.as_bytes());
     bytes.put_u8(0);
 
+    // Application name
+    bytes.put(&b"application_name\0"[..]);
+    bytes.put_slice(&b"pgcat\0"[..]);
+
     // Database
     bytes.put(&b"database\0"[..]);
     bytes.put_slice(database.as_bytes());
@@ -731,6 +735,21 @@ impl BytesMutReader for Cursor<&BytesMut> {
     }
 }
 
+impl BytesMutReader for BytesMut {
+    /// Should only be used when reading strings from the message protocol.
+    /// Can be used to read multiple strings from the same message which are separated by the null byte
+    fn read_string(&mut self) -> Result<String, Error> {
+        let null_index = self.iter().position(|&byte| byte == b'\0');
+
+        match null_index {
+            Some(index) => {
+                let string_bytes = self.split_to(index + 1);
+                Ok(String::from_utf8_lossy(&string_bytes[..string_bytes.len() - 1]).to_string())
+            }
+            None => return Err(Error::ParseBytesError("Could not read string".to_string())),
+        }
+    }
+}
 /// Parse (F) message.
 /// See: <https://www.postgresql.org/docs/current/protocol-message-formats.html>
 #[derive(Clone, Debug)]

src/mirrors.rs

@@ -78,7 +78,7 @@ impl MirroredClient {
                     }
 
                     // Incoming data from server (we read to clear the socket buffer and discard the data)
-                    recv_result = server.recv() => {
+                    recv_result = server.recv(None) => {
                         match recv_result {
                             Ok(message) => trace!("Received from mirror: {} {:?}", String::from_utf8_lossy(&message[..]), address.clone()),
                             Err(err) => {

src/pool.rs

@@ -1,7 +1,6 @@
 use arc_swap::ArcSwap;
 use async_trait::async_trait;
 use bb8::{ManageConnection, Pool, PooledConnection, QueueStrategy};
-use bytes::{BufMut, BytesMut};
 use chrono::naive::NaiveDateTime;
 use log::{debug, error, info, warn};
 use once_cell::sync::Lazy;
@@ -25,7 +24,7 @@ use crate::errors::Error;
 
 use crate::auth_passthrough::AuthPassthrough;
 use crate::plugins::prewarmer;
-use crate::server::Server;
+use crate::server::{Server, ServerParameters};
 use crate::sharding::ShardingFunction;
 use crate::stats::{AddressStats, ClientStats, ServerStats};
 
@@ -196,10 +195,10 @@ pub struct ConnectionPool {
     /// that should not be queried.
     banlist: BanList,
 
-    /// The server information (K messages) have to be passed to the
+    /// The server information has to be passed to the
     /// clients on startup. We pre-connect to all shards and replicas
-    /// on pool creation and save the K messages here.
+    /// on pool creation and save the startup parameters here.
-    server_info: Arc<RwLock<BytesMut>>,
+    original_server_parameters: Arc<RwLock<ServerParameters>>,
 
     /// Pool configuration.
     pub settings: PoolSettings,
@@ -445,7 +444,7 @@ impl ConnectionPool {
                     addresses,
                     banlist: Arc::new(RwLock::new(banlist)),
                     config_hash: new_pool_hash_value,
-                    server_info: Arc::new(RwLock::new(BytesMut::new())),
+                    original_server_parameters: Arc::new(RwLock::new(ServerParameters::new())),
                     auth_hash: pool_auth_hash,
                     settings: PoolSettings {
                         pool_mode: match user.pool_mode {
@@ -528,7 +527,7 @@ impl ConnectionPool {
             for server in 0..self.servers(shard) {
                 let databases = self.databases.clone();
                 let validated = Arc::clone(&validated);
-                let pool_server_info = Arc::clone(&self.server_info);
+                let pool_server_parameters = Arc::clone(&self.original_server_parameters);
 
                 let task = tokio::task::spawn(async move {
                     let connection = match databases[shard][server].get().await {
@@ -541,11 +540,10 @@ impl ConnectionPool {
 
                     let proxy = connection;
                     let server = &*proxy;
-                    let server_info = server.server_info();
+                    let server_parameters: ServerParameters = server.server_parameters();
 
-                    let mut guard = pool_server_info.write();
+                    let mut guard = pool_server_parameters.write();
-                    guard.clear();
+                    *guard = server_parameters;
-                    guard.put(server_info.clone());
                     validated.store(true, Ordering::Relaxed);
                 });
 
@@ -557,7 +555,7 @@ impl ConnectionPool {
 
         // TODO: compare server information to make sure
         // all shards are running identical configurations.
-        if self.server_info.read().is_empty() {
+        if !self.validated() {
             error!("Could not validate connection pool");
             return Err(Error::AllServersDown);
         }
@@ -917,8 +915,8 @@ impl ConnectionPool {
         &self.addresses[shard][server]
     }
 
-    pub fn server_info(&self) -> BytesMut {
+    pub fn server_parameters(&self) -> ServerParameters {
-        self.server_info.read().clone()
+        self.original_server_parameters.read().clone()
     }
 
     fn busy_connection_count(&self, address: &Address) -> u32 {

src/server.rs

@@ -3,12 +3,13 @@
 use bytes::{Buf, BufMut, BytesMut};
 use fallible_iterator::FallibleIterator;
 use log::{debug, error, info, trace, warn};
+use once_cell::sync::Lazy;
 use parking_lot::{Mutex, RwLock};
 use postgres_protocol::message;
-use std::collections::{BTreeSet, HashMap};
+use std::collections::{BTreeSet, HashMap, HashSet};
-use std::io::Read;
+use std::mem;
 use std::net::IpAddr;
-use std::sync::Arc;
+use std::sync::{Arc, Once};
 use std::time::SystemTime;
 use tokio::io::{AsyncRead, AsyncReadExt, AsyncWrite, BufStream};
 use tokio::net::TcpStream;
@@ -19,6 +20,7 @@ use crate::config::{get_config, get_prepared_statements_cache_size, Address, Use
 use crate::constants::*;
 use crate::dns_cache::{AddrSet, CACHED_RESOLVER};
 use crate::errors::{Error, ServerIdentifier};
+use crate::messages::BytesMutReader;
 use crate::messages::*;
 use crate::mirrors::MirroringManager;
 use crate::pool::ClientServerMap;
@@ -145,6 +147,124 @@ impl std::fmt::Display for CleanupState {
     }
 }
 
+static TRACKED_PARAMETERS: Lazy<HashSet<String>> = Lazy::new(|| {
+    let mut set = HashSet::new();
+    set.insert("client_encoding".to_string());
+    set.insert("DateStyle".to_string());
+    set.insert("TimeZone".to_string());
+    set.insert("standard_conforming_strings".to_string());
+    set.insert("application_name".to_string());
+    set
+});
+
+#[derive(Debug, Clone)]
+pub struct ServerParameters {
+    parameters: HashMap<String, String>,
+}
+
+impl Default for ServerParameters {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+impl ServerParameters {
+    pub fn new() -> Self {
+        let mut server_parameters = ServerParameters {
+            parameters: HashMap::new(),
+        };
+
+        server_parameters.set_param("client_encoding".to_string(), "UTF8".to_string(), false);
+        server_parameters.set_param("DateStyle".to_string(), "ISO, MDY".to_string(), false);
+        server_parameters.set_param("TimeZone".to_string(), "Etc/UTC".to_string(), false);
+        server_parameters.set_param(
+            "standard_conforming_strings".to_string(),
+            "on".to_string(),
+            false,
+        );
+        server_parameters.set_param("application_name".to_string(), "pgcat".to_string(), false);
+
+        server_parameters
+    }
+
+    /// returns true if a tracked parameter was set, false if it was a non-tracked parameter
+    /// if startup is false, then then only tracked parameters will be set
+    pub fn set_param(&mut self, mut key: String, value: String, startup: bool) {
+        // The startup parameter will send uncapitalized keys but parameter status packets will send capitalized keys
+        if key == "timezone" {
+            key = "TimeZone".to_string();
+        } else if key == "datestyle" {
+            key = "DateStyle".to_string();
+        };
+
+        if TRACKED_PARAMETERS.contains(&key) {
+            self.parameters.insert(key, value);
+        } else {
+            if startup {
+                self.parameters.insert(key, value);
+            }
+        }
+    }
+
+    pub fn set_from_hashmap(&mut self, parameters: &HashMap<String, String>, startup: bool) {
+        // iterate through each and call set_param
+        for (key, value) in parameters {
+            self.set_param(key.to_string(), value.to_string(), startup);
+        }
+    }
+
+    // Gets the diff of the parameters
+    fn compare_params(&self, incoming_parameters: &ServerParameters) -> HashMap<String, String> {
+        let mut diff = HashMap::new();
+
+        // iterate through tracked parameters
+        for key in TRACKED_PARAMETERS.iter() {
+            if let Some(incoming_value) = incoming_parameters.parameters.get(key) {
+                if let Some(value) = self.parameters.get(key) {
+                    if value != incoming_value {
+                        diff.insert(key.to_string(), incoming_value.to_string());
+                    }
+                }
+            }
+        }
+
+        diff
+    }
+
+    pub fn get_application_name(&self) -> &String {
+        // Can unwrap because we set it in the constructor
+        self.parameters.get("application_name").unwrap()
+    }
+
+    fn add_parameter_message(key: &str, value: &str, buffer: &mut BytesMut) {
+        buffer.put_u8(b'S');
+
+        // 4 is len of i32, the plus for the null terminator
+        let len = 4 + key.len() + 1 + value.len() + 1;
+
+        buffer.put_i32(len as i32);
+
+        buffer.put_slice(key.as_bytes());
+        buffer.put_u8(0);
+        buffer.put_slice(value.as_bytes());
+        buffer.put_u8(0);
+    }
+}
+
+impl From<&ServerParameters> for BytesMut {
+    fn from(server_parameters: &ServerParameters) -> Self {
+        let mut bytes = BytesMut::new();
+
+        for (key, value) in &server_parameters.parameters {
+            ServerParameters::add_parameter_message(key, value, &mut bytes);
+        }
+
+        bytes
+    }
+}
+
+// pub fn compare
+
 /// Server state.
 pub struct Server {
     /// Server host, e.g. localhost,
@@ -158,7 +278,7 @@ pub struct Server {
     buffer: BytesMut,
 
     /// Server information the server sent us over on startup.
-    server_info: BytesMut,
+    server_parameters: ServerParameters,
 
     /// Backend id and secret key used for query cancellation.
     process_id: i32,
@@ -347,7 +467,6 @@ impl Server {
 
         startup(&mut stream, username, database).await?;
 
-        let mut server_info = BytesMut::new();
         let mut process_id: i32 = 0;
         let mut secret_key: i32 = 0;
         let server_identifier = ServerIdentifier::new(username, &database);
@@ -359,6 +478,8 @@ impl Server {
             None => None,
         };
 
+        let mut server_parameters = ServerParameters::new();
+
         loop {
             let code = match stream.read_u8().await {
                 Ok(code) => code as char,
@@ -616,9 +737,10 @@ impl Server {
 
                 // ParameterStatus
                 'S' => {
-                    let mut param = vec![0u8; len as usize - 4];
+                    let mut bytes = BytesMut::with_capacity(len as usize - 4);
+                    bytes.resize(len as usize - mem::size_of::<i32>(), b'0');
 
-                    match stream.read_exact(&mut param).await {
+                    match stream.read_exact(&mut bytes[..]).await {
                         Ok(_) => (),
                         Err(_) => {
                             return Err(Error::ServerStartupError(
@@ -628,12 +750,13 @@ impl Server {
                         }
                     };
 
+                    let key = bytes.read_string().unwrap();
+                    let value = bytes.read_string().unwrap();
+
                     // Save the parameter so we can pass it to the client later.
                     // These can be server_encoding, client_encoding, server timezone, Postgres version,
                     // and many more interesting things we should know about the Postgres server we are talking to.
-                    server_info.put_u8(b'S');
+                    server_parameters.set_param(key, value, true);
-                    server_info.put_i32(len);
-                    server_info.put_slice(&param[..]);
                 }
 
                 // BackendKeyData
@@ -675,11 +798,11 @@ impl Server {
                         }
                     };
 
-                    let mut server = Server {
+                    let server = Server {
                         address: address.clone(),
                         stream: BufStream::new(stream),
                         buffer: BytesMut::with_capacity(8196),
-                        server_info,
+                        server_parameters,
                         process_id,
                         secret_key,
                         in_transaction: false,
@@ -691,7 +814,7 @@ impl Server {
                         addr_set,
                         connected_at: chrono::offset::Utc::now().naive_utc(),
                         stats,
-                        application_name: String::new(),
+                        application_name: "pgcat".to_string(),
                         last_activity: SystemTime::now(),
                         mirror_manager: match address.mirrors.len() {
                             0 => None,
@@ -705,8 +828,6 @@ impl Server {
                         prepared_statements: BTreeSet::new(),
                     };
 
-                    server.set_name("pgcat").await?;
-
                     return Ok(server);
                 }
 
@@ -776,7 +897,10 @@ impl Server {
     /// Receive data from the server in response to a client request.
     /// This method must be called multiple times while `self.is_data_available()` is true
     /// in order to receive all data the server has to offer.
-    pub async fn recv(&mut self) -> Result<BytesMut, Error> {
+    pub async fn recv(
+        &mut self,
+        mut client_server_parameters: Option<&mut ServerParameters>,
+    ) -> Result<BytesMut, Error> {
         loop {
             let mut message = match read_message(&mut self.stream).await {
                 Ok(message) => message,
@@ -848,14 +972,13 @@ impl Server {
                         self.in_copy_mode = false;
                     }
 
-                    let mut command_tag = String::new();
+                    match message.read_string() {
-                    match message.reader().read_to_string(&mut command_tag) {
+                        Ok(command) => {
-                        Ok(_) => {
                             // Non-exhaustive list of commands that are likely to change session variables/resources
                             // which can leak between clients. This is a best effort to block bad clients
                             // from poisoning a transaction-mode pool by setting inappropriate session variables
-                            match command_tag.as_str() {
+                            match command.as_str() {
-                                "SET\0" => {
+                                "SET" => {
                                     // We don't detect set statements in transactions
                                     // No great way to differentiate between set and set local
                                     // As a result, we will miss cases when set statements are used in transactions
@@ -865,7 +988,8 @@ impl Server {
                                         self.cleanup_state.needs_cleanup_set = true;
                                     }
                                 }
-                                "PREPARE\0" => {
+
+                                "PREPARE" => {
                                     debug!("Server connection marked for clean up");
                                     self.cleanup_state.needs_cleanup_prepare = true;
                                 }
@@ -879,6 +1003,17 @@ impl Server {
                     }
                 }
 
+                'S' => {
+                    let key = message.read_string().unwrap();
+                    let value = message.read_string().unwrap();
+
+                    if let Some(client_server_parameters) = client_server_parameters.as_mut() {
+                        client_server_parameters.set_param(key.clone(), value.clone(), false);
+                    }
+
+                    self.server_parameters.set_param(key, value, false);
+                }
+
                 // DataRow
                 'D' => {
                     // More data is available after this message, this is not the end of the reply.
@@ -1089,9 +1224,28 @@ impl Server {
     }
 
     /// Get server startup information to forward it to the client.
-    /// Not used at the moment.
+    pub fn server_parameters(&self) -> ServerParameters {
-    pub fn server_info(&self) -> BytesMut {
+        self.server_parameters.clone()
-        self.server_info.clone()
+    }
+
+    pub async fn sync_parameters(&mut self, parameters: &ServerParameters) -> Result<(), Error> {
+        let parameter_diff = self.server_parameters.compare_params(parameters);
+
+        if parameter_diff.is_empty() {
+            return Ok(());
+        }
+
+        let mut query = String::from("");
+
+        for (key, value) in parameter_diff {
+            query.push_str(&format!("SET {} TO '{}';", key, value));
+        }
+
+        let res = self.query(&query).await;
+
+        self.cleanup_state.reset();
+
+        res
     }
 
     /// Indicate that this server connection cannot be re-used and must be discarded.
@@ -1125,7 +1279,7 @@ impl Server {
         self.send(&query).await?;
 
         loop {
-            let _ = self.recv().await?;
+            let _ = self.recv(None).await?;
 
             if !self.data_available {
                 break;
@@ -1166,24 +1320,6 @@ impl Server {
         Ok(())
     }
 
-    /// A shorthand for `SET application_name = $1`.
-    pub async fn set_name(&mut self, name: &str) -> Result<(), Error> {
-        if self.application_name != name {
-            self.application_name = name.to_string();
-            // We don't want `SET application_name` to mark the server connection
-            // as needing cleanup
-            let needs_cleanup_before = self.cleanup_state;
-
-            let result = Ok(self
-                .query(&format!("SET application_name = '{}'", name))
-                .await?);
-            self.cleanup_state = needs_cleanup_before;
-            result
-        } else {
-            Ok(())
-        }
-    }
-
     /// get Server stats
     pub fn stats(&self) -> Arc<ServerStats> {
         self.stats.clone()
@@ -1241,7 +1377,7 @@ impl Server {
         .await?;
         debug!("Connected!, sending query.");
         server.send(&simple_query(query)).await?;
-        let mut message = server.recv().await?;
+        let mut message = server.recv(None).await?;
 
         Ok(parse_query_message(&mut message).await?)
     }

tests/ruby/helpers/pgcat_process.rb

@@ -112,10 +112,16 @@ class PgcatProcess
     "postgresql://#{username}:#{password}@0.0.0.0:#{@port}/pgcat"
   end
 
-  def connection_string(pool_name, username, password = nil)
+  def connection_string(pool_name, username, password = nil, parameters: {})
     cfg = current_config
     user_idx, user_obj = cfg["pools"][pool_name]["users"].detect { |k, user| user["username"] == username }
-    "postgresql://#{username}:#{password || user_obj["password"]}@0.0.0.0:#{@port}/#{pool_name}"
+    connection_string = "postgresql://#{username}:#{password || user_obj["password"]}@0.0.0.0:#{@port}/#{pool_name}"
+  
+    # Add the additional parameters to the connection string
+    parameter_string = parameters.map { |key, value| "#{key}=#{value}" }.join("&")
+    connection_string += "?#{parameter_string}" unless parameter_string.empty?
+  
+    connection_string
   end
 
   def example_connection_string

tests/ruby/misc_spec.rb

@@ -294,6 +294,30 @@ describe "Miscellaneous" do
 
         expect(processes.primary.count_query("DISCARD ALL")).to eq(10)
       end
+
+      it "Respects tracked parameters on startup" do
+        conn = PG::connect(processes.pgcat.connection_string("sharded_db", "sharding_user", parameters: { "application_name" => "my_pgcat_test" }))
+
+        expect(conn.async_exec("SHOW application_name")[0]["application_name"]).to eq("my_pgcat_test")
+        conn.close
+      end
+
+      it "Respect tracked parameter on set statemet" do
+        conn = PG::connect(processes.pgcat.connection_string("sharded_db", "sharding_user"))
+
+        conn.async_exec("SET application_name to 'my_pgcat_test'")
+        expect(conn.async_exec("SHOW application_name")[0]["application_name"]).to eq("my_pgcat_test")
+      end
+
+
+      it "Ignore untracked parameter on set statemet" do
+        conn = PG::connect(processes.pgcat.connection_string("sharded_db", "sharding_user"))
+        orignal_statement_timeout = conn.async_exec("SHOW statement_timeout")[0]["statement_timeout"]
+
+        conn.async_exec("SET statement_timeout to 1500")
+        expect(conn.async_exec("SHOW statement_timeout")[0]["statement_timeout"]).to eq(orignal_statement_timeout)
+      end
+ 
     end
 
     context "transaction mode with transactions" do