feat: support pg_namespace, pg_class and related psql command (#4428)

* feat: add function 'pg_catalog.pg_table_is_visible'q

* feat: add 'pg_class' and 'pg_namespace', now we can run '\d' and '\dt'!

* refactor: move memory_table::tables to utils::tables

* refactor: move out predicate to system_schema to reuse it

* feat: predicates pushdown

* test: add pg_namespace, pg_class related sqlness test

* fix: typos and license header

* fix: sqlness test

* refactor: use `expect` instead of `unwrap` here

* refactor: remove the `information_schema::utils` mod

* doc: make the comment in pg_get_userbyid more precise

* doc: add TODO and comment in pg_catalog

* fix: typo

* fix: sqlness

* doc: change to comment on PGClassBuilder to TODO

src/common/function/src/scalars/expression/unary.rs

@@ -19,8 +19,6 @@ use snafu::ResultExt;
 
 use crate::scalars::expression::ctx::EvalContext;
 
-/// TODO: remove the allow_unused when it's used.
-#[allow(unused)]
 pub fn scalar_unary_op<L: Scalar, O: Scalar, F>(
     l: &VectorRef,
     f: F,

src/common/function/src/system.rs

@@ -14,6 +14,7 @@
 
 mod build;
 mod database;
+mod pg_catalog;
 mod procedure_state;
 mod timezone;
 mod version;
@@ -22,6 +23,7 @@ use std::sync::Arc;
 
 use build::BuildFunction;
 use database::DatabaseFunction;
+use pg_catalog::PGCatalogFunction;
 use procedure_state::ProcedureStateFunction;
 use timezone::TimezoneFunction;
 use version::VersionFunction;
@@ -37,5 +39,6 @@ impl SystemFunction {
         registry.register(Arc::new(DatabaseFunction));
         registry.register(Arc::new(TimezoneFunction));
         registry.register(Arc::new(ProcedureStateFunction));
+        PGCatalogFunction::register(registry);
     }
 }

src/common/function/src/system/pg_catalog.rs

@@ -0,0 +1,39 @@
+// Copyright 2023 Greptime Team
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+mod pg_get_userbyid;
+mod table_is_visible;
+
+use std::sync::Arc;
+
+use pg_get_userbyid::PGGetUserByIdFunction;
+use table_is_visible::PGTableIsVisibleFunction;
+
+use crate::function_registry::FunctionRegistry;
+
+#[macro_export]
+macro_rules! pg_catalog_func_fullname {
+    ($name:literal) => {
+        concat!("pg_catalog.", $name)
+    };
+}
+
+pub(super) struct PGCatalogFunction;
+
+impl PGCatalogFunction {
+    pub fn register(registry: &FunctionRegistry) {
+        registry.register(Arc::new(PGTableIsVisibleFunction));
+        registry.register(Arc::new(PGGetUserByIdFunction));
+    }
+}

src/common/function/src/system/pg_catalog/pg_get_userbyid.rs

@@ -0,0 +1,72 @@
+// Copyright 2023 Greptime Team
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+use std::fmt::{self};
+use std::sync::Arc;
+
+use common_query::error::Result;
+use common_query::prelude::{Signature, Volatility};
+use datatypes::prelude::{ConcreteDataType, DataType, VectorRef};
+use datatypes::types::LogicalPrimitiveType;
+use datatypes::with_match_primitive_type_id;
+use num_traits::AsPrimitive;
+
+use crate::function::{Function, FunctionContext};
+use crate::scalars::expression::{scalar_unary_op, EvalContext};
+
+#[derive(Clone, Debug, Default)]
+pub struct PGGetUserByIdFunction;
+
+const NAME: &str = crate::pg_catalog_func_fullname!("pg_get_userbyid");
+
+impl fmt::Display for PGGetUserByIdFunction {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(f, crate::pg_catalog_func_fullname!("PG_GET_USERBYID"))
+    }
+}
+
+impl Function for PGGetUserByIdFunction {
+    fn name(&self) -> &str {
+        NAME
+    }
+
+    fn return_type(&self, _input_types: &[ConcreteDataType]) -> Result<ConcreteDataType> {
+        Ok(ConcreteDataType::string_datatype())
+    }
+
+    fn signature(&self) -> Signature {
+        Signature::uniform(
+            1,
+            vec![ConcreteDataType::uint32_datatype()],
+            Volatility::Immutable,
+        )
+    }
+
+    fn eval(&self, _func_ctx: FunctionContext, columns: &[VectorRef]) -> Result<VectorRef> {
+        with_match_primitive_type_id!(columns[0].data_type().logical_type_id(), |$T| {
+            let col = scalar_unary_op::<<$T as LogicalPrimitiveType>::Native, String, _>(&columns[0], pg_get_user_by_id, &mut EvalContext::default())?;
+            Ok(Arc::new(col))
+        }, {
+            unreachable!()
+        })
+    }
+}
+
+fn pg_get_user_by_id<I>(table_oid: Option<I>, _ctx: &mut EvalContext) -> Option<String>
+where
+    I: AsPrimitive<u32>,
+{
+    // TODO(J0HN50N133): We lack way to get the user_info by a numeric value. Once we have it, we can implement this function.
+    table_oid.map(|_| "".to_string())
+}

src/common/function/src/system/pg_catalog/table_is_visible.rs

@@ -0,0 +1,72 @@
+// Copyright 2023 Greptime Team
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+use std::fmt::{self};
+use std::sync::Arc;
+
+use common_query::error::Result;
+use common_query::prelude::{Signature, Volatility};
+use datatypes::prelude::{ConcreteDataType, DataType, VectorRef};
+use datatypes::types::LogicalPrimitiveType;
+use datatypes::with_match_primitive_type_id;
+use num_traits::AsPrimitive;
+
+use crate::function::{Function, FunctionContext};
+use crate::scalars::expression::{scalar_unary_op, EvalContext};
+
+#[derive(Clone, Debug, Default)]
+pub struct PGTableIsVisibleFunction;
+
+const NAME: &str = crate::pg_catalog_func_fullname!("pg_table_is_visible");
+
+impl fmt::Display for PGTableIsVisibleFunction {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        write!(f, crate::pg_catalog_func_fullname!("PG_TABLE_IS_VISIBLE"))
+    }
+}
+
+impl Function for PGTableIsVisibleFunction {
+    fn name(&self) -> &str {
+        NAME
+    }
+
+    fn return_type(&self, _input_types: &[ConcreteDataType]) -> Result<ConcreteDataType> {
+        Ok(ConcreteDataType::boolean_datatype())
+    }
+
+    fn signature(&self) -> Signature {
+        Signature::uniform(
+            1,
+            vec![ConcreteDataType::uint32_datatype()],
+            Volatility::Immutable,
+        )
+    }
+
+    fn eval(&self, _func_ctx: FunctionContext, columns: &[VectorRef]) -> Result<VectorRef> {
+        with_match_primitive_type_id!(columns[0].data_type().logical_type_id(), |$T| {
+            let col = scalar_unary_op::<<$T as LogicalPrimitiveType>::Native, bool, _>(&columns[0], pg_table_is_visible, &mut EvalContext::default())?;
+            Ok(Arc::new(col))
+        }, {
+            unreachable!()
+        })
+    }
+}
+
+fn pg_table_is_visible<I>(table_oid: Option<I>, _ctx: &mut EvalContext) -> Option<bool>
+where
+    I: AsPrimitive<u32>,
+{
+    // There is no table visibility in greptime, so we always return true
+    table_oid.map(|_| true)
+}