feat: returning warning instead of error on unsupported SET stateme…

…nt (#4761)

* feat: add capability to send warning to pgclient

* fix: refactor query context to carry query scope data

* feat: return a warning for unsupported postgres statement

src/operator/src/statement.rs

@@ -46,7 +46,7 @@ use datafusion_expr::LogicalPlan;
 use partition::manager::{PartitionRuleManager, PartitionRuleManagerRef};
 use query::parser::QueryStatement;
 use query::QueryEngineRef;
-use session::context::QueryContextRef;
+use session::context::{Channel, QueryContextRef};
 use session::table_name::table_idents_to_full_name;
 use snafu::{ensure, OptionExt, ResultExt};
 use sql::statements::copy::{CopyDatabase, CopyDatabaseArgument, CopyTable, CopyTableArgument};
@@ -338,10 +338,18 @@ impl StatementExecutor {
 
             "CLIENT_ENCODING" => validate_client_encoding(set_var)?,
             _ => {
-                return NotSupportedSnafu {
-                    feat: format!("Unsupported set variable {}", var_name),
+                // for postgres, we give unknown SET statements a warning with
+                //  success, this is prevent the SET call becoming a blocker
+                //  of connection establishment
+                //
+                if query_ctx.channel() == Channel::Postgres {
+                    query_ctx.set_warning(format!("Unsupported set variable {}", var_name));
+                } else {
+                    return NotSupportedSnafu {
+                        feat: format!("Unsupported set variable {}", var_name),
+                    }
+                    .fail();
                 }
-                .fail()
             }
         }
         Ok(Output::new_with_affected_rows(0))

src/servers/src/postgres/handler.rs

@@ -12,6 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+use std::fmt::Debug;
 use std::sync::Arc;
 
 use async_trait::async_trait;
@@ -23,7 +24,7 @@ use common_telemetry::{debug, error, tracing};
 use datafusion_common::ParamValues;
 use datatypes::prelude::ConcreteDataType;
 use datatypes::schema::SchemaRef;
-use futures::{future, stream, Stream, StreamExt};
+use futures::{future, stream, Sink, SinkExt, Stream, StreamExt};
 use pgwire::api::portal::{Format, Portal};
 use pgwire::api::query::{ExtendedQueryHandler, SimpleQueryHandler};
 use pgwire::api::results::{
@@ -32,6 +33,7 @@ use pgwire::api::results::{
 use pgwire::api::stmt::{QueryParser, StoredStatement};
 use pgwire::api::{ClientInfo, Type};
 use pgwire::error::{ErrorInfo, PgWireError, PgWireResult};
+use pgwire::messages::PgWireBackendMessage;
 use query::query_engine::DescribeResult;
 use session::context::QueryContextRef;
 use session::Session;
@@ -49,11 +51,13 @@ impl SimpleQueryHandler for PostgresServerHandlerInner {
     #[tracing::instrument(skip_all, fields(protocol = "postgres"))]
     async fn do_query<'a, C>(
         &self,
-        _client: &mut C,
+        client: &mut C,
         query: &'a str,
     ) -> PgWireResult<Vec<Response<'a>>>
     where
-        C: ClientInfo + Unpin + Send + Sync,
+        C: ClientInfo + Sink<PgWireBackendMessage> + Unpin + Send + Sync,
+        C::Error: Debug,
+        PgWireError: From<<C as Sink<PgWireBackendMessage>>::Error>,
     {
         let query_ctx = self.session.new_query_context();
         let db = query_ctx.get_db_string();
@@ -67,6 +71,7 @@ impl SimpleQueryHandler for PostgresServerHandlerInner {
         }
 
         if let Some(resps) = fixtures::process(query, query_ctx.clone()) {
+            send_warning_opt(client, query_ctx).await?;
             Ok(resps)
         } else {
             let outputs = self.query_handler.do_query(query, query_ctx.clone()).await;
@@ -79,11 +84,34 @@ impl SimpleQueryHandler for PostgresServerHandlerInner {
                 results.push(resp);
             }
 
+            send_warning_opt(client, query_ctx).await?;
             Ok(results)
         }
     }
 }
 
+async fn send_warning_opt<C>(client: &mut C, query_context: QueryContextRef) -> PgWireResult<()>
+where
+    C: Sink<PgWireBackendMessage> + Unpin + Send + Sync,
+    C::Error: Debug,
+    PgWireError: From<<C as Sink<PgWireBackendMessage>>::Error>,
+{
+    if let Some(warning) = query_context.warning() {
+        client
+            .feed(PgWireBackendMessage::NoticeResponse(
+                ErrorInfo::new(
+                    PgErrorSeverity::Warning.to_string(),
+                    PgErrorCode::Ec01000.code(),
+                    warning.to_string(),
+                )
+                .into(),
+            ))
+            .await?;
+    }
+
+    Ok(())
+}
+
 pub(crate) fn output_to_query_response<'a>(
     query_ctx: QueryContextRef,
     output: Result<Output>,
@@ -247,12 +275,14 @@ impl ExtendedQueryHandler for PostgresServerHandlerInner {
 
     async fn do_query<'a, C>(
         &self,
-        _client: &mut C,
+        client: &mut C,
         portal: &'a Portal<Self::Statement>,
         _max_rows: usize,
     ) -> PgWireResult<Response<'a>>
     where
-        C: ClientInfo + Unpin + Send + Sync,
+        C: ClientInfo + Sink<PgWireBackendMessage> + Unpin + Send + Sync,
+        C::Error: Debug,
+        PgWireError: From<<C as Sink<PgWireBackendMessage>>::Error>,
     {
         let query_ctx = self.session.new_query_context();
         let db = query_ctx.get_db_string();
@@ -268,6 +298,7 @@ impl ExtendedQueryHandler for PostgresServerHandlerInner {
         }
 
         if let Some(mut resps) = fixtures::process(&sql_plan.query, query_ctx.clone()) {
+            send_warning_opt(client, query_ctx).await?;
             // if the statement matches our predefined rules, return it early
             return Ok(resps.remove(0));
         }
@@ -297,6 +328,7 @@ impl ExtendedQueryHandler for PostgresServerHandlerInner {
                 .remove(0)
         };
 
+        send_warning_opt(client, query_ctx.clone()).await?;
         output_to_query_response(query_ctx, output, &portal.result_column_format)
     }
 

src/servers/src/postgres/types.rs

@@ -37,7 +37,7 @@ use session::session_config::PGByteaOutputValue;
 
 use self::bytea::{EscapeOutputBytea, HexOutputBytea};
 use self::datetime::{StylingDate, StylingDateTime};
-pub use self::error::PgErrorCode;
+pub use self::error::{PgErrorCode, PgErrorSeverity};
 use self::interval::PgInterval;
 use crate::error::{self as server_error, Error, Result};
 use crate::SqlPlan;

src/servers/src/postgres/types/error.rs

@@ -19,7 +19,7 @@ use strum::{AsRefStr, Display, EnumIter, EnumMessage};
 
 #[derive(Display, Debug, PartialEq)]
 #[allow(dead_code)]
-enum ErrorSeverity {
+pub enum PgErrorSeverity {
     #[strum(serialize = "INFO")]
     Info,
     #[strum(serialize = "DEBUG")]
@@ -335,23 +335,23 @@ pub enum PgErrorCode {
 }
 
 impl PgErrorCode {
-    fn severity(&self) -> ErrorSeverity {
+    fn severity(&self) -> PgErrorSeverity {
         match self {
-            PgErrorCode::Ec00000 => ErrorSeverity::Info,
-            PgErrorCode::Ec01000 => ErrorSeverity::Warning,
+            PgErrorCode::Ec00000 => PgErrorSeverity::Info,
+            PgErrorCode::Ec01000 => PgErrorSeverity::Warning,
 
             PgErrorCode::EcXX000 | PgErrorCode::Ec42P14 | PgErrorCode::Ec22023 => {
-                ErrorSeverity::Error
+                PgErrorSeverity::Error
             }
             PgErrorCode::Ec28000 | PgErrorCode::Ec28P01 | PgErrorCode::Ec3D000 => {
-                ErrorSeverity::Fatal
+                PgErrorSeverity::Fatal
             }
 
-            _ => ErrorSeverity::Error,
+            _ => PgErrorSeverity::Error,
         }
     }
 
-    fn code(&self) -> String {
+    pub(crate) fn code(&self) -> String {
         self.as_ref()[2..].to_string()
     }
 
@@ -428,33 +428,33 @@ mod tests {
     use common_error::status_code::StatusCode;
     use strum::{EnumMessage, IntoEnumIterator};
 
-    use super::{ErrorInfo, ErrorSeverity, PgErrorCode};
+    use super::{ErrorInfo, PgErrorCode, PgErrorSeverity};
 
     #[test]
     fn test_error_severity() {
         // test for ErrorSeverity enum
-        assert_eq!("INFO", ErrorSeverity::Info.to_string());
-        assert_eq!("DEBUG", ErrorSeverity::Debug.to_string());
-        assert_eq!("NOTICE", ErrorSeverity::Notice.to_string());
-        assert_eq!("WARNING", ErrorSeverity::Warning.to_string());
+        assert_eq!("INFO", PgErrorSeverity::Info.to_string());
+        assert_eq!("DEBUG", PgErrorSeverity::Debug.to_string());
+        assert_eq!("NOTICE", PgErrorSeverity::Notice.to_string());
+        assert_eq!("WARNING", PgErrorSeverity::Warning.to_string());
 
-        assert_eq!("ERROR", ErrorSeverity::Error.to_string());
-        assert_eq!("FATAL", ErrorSeverity::Fatal.to_string());
-        assert_eq!("PANIC", ErrorSeverity::Panic.to_string());
+        assert_eq!("ERROR", PgErrorSeverity::Error.to_string());
+        assert_eq!("FATAL", PgErrorSeverity::Fatal.to_string());
+        assert_eq!("PANIC", PgErrorSeverity::Panic.to_string());
 
         // test for severity method
         for code in PgErrorCode::iter() {
             let name = code.as_ref();
             assert_eq!("Ec", &name[0..2]);
 
             if name.starts_with("Ec00") {
-                assert_eq!(ErrorSeverity::Info, code.severity());
+                assert_eq!(PgErrorSeverity::Info, code.severity());
             } else if name.starts_with("Ec01") {
-                assert_eq!(ErrorSeverity::Warning, code.severity());
+                assert_eq!(PgErrorSeverity::Warning, code.severity());
             } else if name.starts_with("Ec28") || name.starts_with("Ec3D") {
-                assert_eq!(ErrorSeverity::Fatal, code.severity());
+                assert_eq!(PgErrorSeverity::Fatal, code.severity());
             } else {
-                assert_eq!(ErrorSeverity::Error, code.severity());
+                assert_eq!(PgErrorSeverity::Error, code.severity());
             }
         }
     }

src/session/src/context.rs

@@ -40,7 +40,9 @@ pub struct QueryContext {
     current_catalog: String,
     // we use Arc<RwLock>> for modifiable fields
     #[builder(default)]
-    mutable_inner: Arc<RwLock<MutableInner>>,
+    mutable_session_data: Arc<RwLock<MutableInner>>,
+    #[builder(default)]
+    mutable_query_context_data: Arc<RwLock<QueryContextMutableFields>>,
     sql_dialect: Arc<dyn Dialect + Send + Sync>,
     #[builder(default)]
     extensions: HashMap<String, String>,
@@ -52,6 +54,12 @@ pub struct QueryContext {
     channel: Channel,
 }
 
+/// This fields hold data that is only valid to current query context
+#[derive(Debug, Builder, Clone, Default)]
+pub struct QueryContextMutableFields {
+    warning: Option<String>,
+}
+
 impl Display for QueryContext {
     fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
         write!(
@@ -65,21 +73,26 @@ impl Display for QueryContext {
 
 impl QueryContextBuilder {
     pub fn current_schema(mut self, schema: String) -> Self {
-        if self.mutable_inner.is_none() {
-            self.mutable_inner = Some(Arc::new(RwLock::new(MutableInner::default())));
+        if self.mutable_session_data.is_none() {
+            self.mutable_session_data = Some(Arc::new(RwLock::new(MutableInner::default())));
         }
 
         // safe for unwrap because previous none check
-        self.mutable_inner.as_mut().unwrap().write().unwrap().schema = schema;
+        self.mutable_session_data
+            .as_mut()
+            .unwrap()
+            .write()
+            .unwrap()
+            .schema = schema;
         self
     }
 
     pub fn timezone(mut self, timezone: Timezone) -> Self {
-        if self.mutable_inner.is_none() {
-            self.mutable_inner = Some(Arc::new(RwLock::new(MutableInner::default())));
+        if self.mutable_session_data.is_none() {
+            self.mutable_session_data = Some(Arc::new(RwLock::new(MutableInner::default())));
         }
 
-        self.mutable_inner
+        self.mutable_session_data
             .as_mut()
             .unwrap()
             .write()
@@ -120,7 +133,7 @@ impl From<QueryContext> for api::v1::QueryContext {
     fn from(
         QueryContext {
             current_catalog,
-            mutable_inner,
+            mutable_session_data: mutable_inner,
             extensions,
             channel,
             ..
@@ -182,11 +195,11 @@ impl QueryContext {
     }
 
     pub fn current_schema(&self) -> String {
-        self.mutable_inner.read().unwrap().schema.clone()
+        self.mutable_session_data.read().unwrap().schema.clone()
     }
 
     pub fn set_current_schema(&self, new_schema: &str) {
-        self.mutable_inner.write().unwrap().schema = new_schema.to_string();
+        self.mutable_session_data.write().unwrap().schema = new_schema.to_string();
     }
 
     pub fn current_catalog(&self) -> &str {
@@ -208,19 +221,19 @@ impl QueryContext {
     }
 
     pub fn timezone(&self) -> Timezone {
-        self.mutable_inner.read().unwrap().timezone.clone()
+        self.mutable_session_data.read().unwrap().timezone.clone()
     }
 
     pub fn set_timezone(&self, timezone: Timezone) {
-        self.mutable_inner.write().unwrap().timezone = timezone;
+        self.mutable_session_data.write().unwrap().timezone = timezone;
     }
 
     pub fn current_user(&self) -> UserInfoRef {
-        self.mutable_inner.read().unwrap().user_info.clone()
+        self.mutable_session_data.read().unwrap().user_info.clone()
     }
 
     pub fn set_current_user(&self, user: UserInfoRef) {
-        self.mutable_inner.write().unwrap().user_info = user;
+        self.mutable_session_data.write().unwrap().user_info = user;
     }
 
     pub fn set_extension<S1: Into<String>, S2: Into<String>>(&mut self, key: S1, value: S2) {
@@ -257,6 +270,18 @@ impl QueryContext {
     pub fn set_channel(&mut self, channel: Channel) {
         self.channel = channel;
     }
+
+    pub fn warning(&self) -> Option<String> {
+        self.mutable_query_context_data
+            .read()
+            .unwrap()
+            .warning
+            .clone()
+    }
+
+    pub fn set_warning(&self, msg: String) {
+        self.mutable_query_context_data.write().unwrap().warning = Some(msg);
+    }
 }
 
 impl QueryContextBuilder {
@@ -266,7 +291,8 @@ impl QueryContextBuilder {
             current_catalog: self
                 .current_catalog
                 .unwrap_or_else(|| DEFAULT_CATALOG_NAME.to_string()),
-            mutable_inner: self.mutable_inner.unwrap_or_default(),
+            mutable_session_data: self.mutable_session_data.unwrap_or_default(),
+            mutable_query_context_data: self.mutable_query_context_data.unwrap_or_default(),
             sql_dialect: self
                 .sql_dialect
                 .unwrap_or_else(|| Arc::new(GreptimeDbDialect {})),

src/session/src/lib.rs

@@ -76,7 +76,7 @@ impl Session {
             // catalog is not allowed for update in query context so we use
             // string here
             .current_catalog(self.catalog.read().unwrap().clone())
-            .mutable_inner(self.mutable_inner.clone())
+            .mutable_session_data(self.mutable_inner.clone())
             .sql_dialect(self.conn_info.channel.dialect())
             .configuration_parameter(self.configuration_variables.clone())
             .channel(self.conn_info.channel)